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Responses of Quaternary rainforest vertebrates to climate change in Australia
Abstract
A new middle Pleistocene vertebrate fossil record from eastern Australia, dated by U disequilibrium series, records the first Quaternary record of an Australian tropical rainforest fauna. This exceptionally rich fauna underwent extinction after a long period of relative faunal stability, spanning several glacial cycles, and persisted probably until 280 000 years ago. Some time between 280 000 and 205 000 years ago the rainforest fauna was replaced by a xeric-adapted fauna. Since that time, the xeric-adapted fauna was replaced by a mesic-adapted fauna which was established by the Holocene. This is the first vertebrate faunal evidence in Australia of the middle Pleistocene Mid-Brunhes Climatic Event (MBE), a major climatic reorganisation that led to increased aridity in northern Australia from around 300 000 years ago. Several independent palaeoclimate proxies suggest that the climatic shift to aridity was due to increased climatic variability and weakened northern monsoons, which may be manifested in the extinction of the aseasonal rainforest fauna and its replacement by an arid-adapted fauna. We extend the temporal ranges of several taxa from the Pliocene into the middle Pleistocene. We also reveal a longer palaeobiogeographic connection of rainforest taxa and lineages shared between New Guinea and Australia than was previously thought and show that their extinction on mainland Australia occurred sometime after 280 000 years ago.
... It is, however, consistent with conclusions drawn by Murray (1992) about the timing of diprotodontid dispersal into New Guinea. If supported by further evidence in the future, it also might help explain the purported existence of several species of Dendrolagus in the middle Pleistocene of eastern Australia, including at least one member of the New Guinea clade, along with other marsupial forms that are said to be more allied to modern New Guinean rather than modern Australian taxa (Hocknull et al. 2007). That is, the absence of certain New Guinean clades from the Australian mainland today might not necessarily reflect long-term endemism in New Guinea, but rather their extinction in Australia (Beck 2017). ...
... indet. 1 persisted into the middle Pleistocene, where it is represented in cave-fill deposits at Mt Etna in coastal northeastern Queensland (Hocknull 2005a,b). The diverse Mt Etna assemblage reflects a mix of habitats, including tropical rainforest, and purportedly includes remains of up to four species of Dendrolagus not yet identifiable to species level (Hocknull et al. 2007). Until at least as recently as the middle Pleistocene, tree-kangaroos had a far broader distribution ( Figure 1) through a greater array of habitats than they do now. ...
... 300 ka) is a calcaneus of B. sp. indet. 1 from the Mt Etna caves (Hocknull 2005a, b;Hocknull et al. 2007). For the others we cannot currently do better than middle or late Pleistocene, which has long been a deficiency that has beset our understanding of change in Quaternary assemblages and extinction trajectories (Prideaux 2006). ...
Tree-kangaroos of the genus Dendrolagus occupy forest habitats of New Guinea and extreme northeastern Australia, but their evolutionary history is poorly known. Descriptions in the 2000s of near-complete Pleistocene skeletons belonging to larger-bodied species in the now-extinct genus Bohra broadened our understanding of morphological variation in the group and have since helped us to identify unassigned fossils in museum collections, as well as to reassign species previously placed in other genera. Here we describe these fossils and analyse tree-kangaroo systematics via comparative osteology. Including B. planei sp. nov., B. bandharr comb. nov. and B. bila comb. nov., we recognise the existence of at least seven late Cenozoic species of Bohra, with a maximum of three in any one assemblage. All tree-kangaroos (Dendrolagina subtribe nov.) exhibit skeletal adaptations reflective of greater joint flexibility and manoeuvrability, particularly in the hindlimb, compared with other macropodids. The Pliocene species of Bohra retained the stepped calcaneocuboid articulation characteristic of ground-dwelling macropodids, but this became smoothed to allow greater hindfoot rotation in the later species of Bohra and in Dendrolagus. Tree-kangaroo diversification may have been tied to the expansion of forest habitats in the early Pliocene. Following the onset of late Pliocene aridity, some tree-kangaroo species took advantage of the consequent spread of more open habitats, becoming among the largest late Cenozoic tree-dwellers on the continent. Arboreal Old World primates and late Quaternary lemurs may be the closest ecological analogues to the species of Bohra.
... Fossils and subfossils of multiple species of Notomys have been found in various cave surficial deposits, usually in owl pellets under rocky overhangs or within crevices (Smith 1977, Lundelius 1983, Baynes 1984, Copley et al. 1989, Robinson et al. 2000. In Queensland, the oldest fossils of the genus are from a Chibanian deposit (170-205 ka) at Mount Etna (Hocknull et al. 2007). Phylogenetic analysis indicates that recent extinctions amongst various CWR murine taxa were not restricted to certain clades but are instead strongly correlated with body size (Roycroft et al. 2021). ...
... Additionally, many species of Notomys are absent from the fossil record, although this may be due to lack of adequate sampling. Some studies have used modern dating techniques and demonstrated that species such as N. longicaudatus has a temporal record extending back to the middle Pleistocene (ca 165 ka) (see Hocknull et al. 2007, Price et al. 2020. ...
... The discovery of N. magnus, along with those mentioned by Start et al. (2012) and C. yirratji (Travouillon et al. 2019), are indicative of the decline (and possibly collapse) of small mammal assemblages in the dry northern tropics of Australia. This is also true of many other pre-European extinct taxa that fall within the CWR range (such as murids, dasyurids and peramelids) as documented in Hocknull (2005), Hocknull et al. (2007) and Price et al. (2020). This raises an important question. ...
... Assignment of isolated teeth to Dasyuridae has proven challenging, in particular those from Oligocene-Miocene deposits, due to an absence of unequivocal dental synapomorphies that may characterize the family (Wroe 1997a, 2003, Long et al. 2002, Archer & Hand 2006, although see Murray & Megirian 2006 for an alternative perspective). Hocknull (2005) described diverse rainforest assemblages from cave sites at Mount Etna, eastern central Queensland ( Fig. 1), that are now known to be mid-Pleistocene in age (Hocknull et al. 2007). Dasyurid diversity in these is unusually high in comparison to other rainforest assemblages, and contains several previously undescribed taxa (Cramb et al. 2009). ...
... Given that the majority of dasyurid species described solely on the basis of fossils are from Pliocene or older deposits (Long et al. 2002, Wroe 2003, this has created the impression that dasyurid assemblages were relatively stable during the Quaternary. In contrast, middle Pleistocene faunas from Mount Etna challenge that assumption in that they contain high diversity assemblages of dasyurids dominated by prehistorically extinct species, including members of multiple previously unknown genera (Hocknull 2005, Hocknull et al. 2007, Cramb et al. 2009, Cramb & Hocknull 2010. ...
... Hocknull (2005) and Hocknull et al. (2007) described the geological, sedimentological and taphonomical settings for the fossil deposits yielding dasyurid remains in the Mount Etna region. Fossil dasyurids have been recovered from all known deposits at Mount Etna spanning approximately the last 500,000 years (500 ka). ...
Urrayira whitei gen. et sp. nov. is described based on dental remains from middle Pleistocene cave sites at Mount Etna, Queensland. Its higher-level systematic affinities are unclear but it appears to be a dasyuromorphian. It is unusual in having a specialized reduced dentition characterized by reduction of the stylar cusps, protocone and talonid, resulting in an incipiently zalambdodont morphology that emphasizes the shearing crests. In addition, only two upper premolars are present, and we assume that it is P3 that has been suppressed, as has occurred multiple times within Dasyuridae. Maximum parsimony and undated Bayesian analyses of a 174 morphological character matrix intended to resolve relationships within Dasyuromorphia, with a molecular scaffold enforced, suggest that Urrayira is a dasyurid. In the maximum parsimony analysis, Urrayira is sister to Planigale gilesi (which also lacks P3), whereas in the undated Bayesian analysis, Urrayira resolves as part of a trichotomy at the base of Dasyuridae, together with Sminthopsinae and Dasyurinae; however, support values are generally low throughout the tree. While the majority of rainforest-adapted taxa in the Mount Etna sites became either extinct or were locally extirpated at, or soon after, 280 ka, there is no evidence that U. whitei gen. et sp. nov. even persisted until that time. Urrayira whitei was likely a rainforest-specialist, thus may have been particularly vulnerable to incipient effects of the Mid-Brunhes climatic shift towards aridity that eventually drove the disappearance of the Mount Etna rainforest and its associated fauna.
Jonathan Cramb* [jonathan.cramb@qm.qld.gov.au], Queensland Museum, PO Box 3300, South Brisbane BC, Queensland 4101, Australia; Scott Hocknull [scott.hocknull@qm.qld.gov.au], Queensland Museum, PO Box 3300, South Brisbane BC, Queensland 4101, Australia; Robin M. D. Beck [r.m.d.beck@salford.ac.uk], School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK; Shimona Kealy [shimona.kealy@anu.edu.au], Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT, 2601, Australia; Gilbert J. Price [g.price1@uq.edu.au], School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
... Assignment of isolated teeth to Dasyuridae has proven challenging, in particular those from Oligocene-Miocene deposits, due to an absence of unequivocal dental synapomorphies that may characterize the family (Wroe 1997a, 2003, Long et al. 2002, Archer & Hand 2006, although see Murray & Megirian 2006 for an alternative perspective). Hocknull (2005) described diverse rainforest assemblages from cave sites at Mount Etna, eastern central Queensland ( Fig. 1), that are now known to be mid-Pleistocene in age (Hocknull et al. 2007). Dasyurid diversity in these is unusually high in comparison to other rainforest assemblages, and contains several previously undescribed taxa (Cramb et al. 2009). ...
... Given that the majority of dasyurid species described solely on the basis of fossils are from Pliocene or older deposits (Long et al. 2002, Wroe 2003, this has created the impression that dasyurid assemblages were relatively stable during the Quaternary. In contrast, middle Pleistocene faunas from Mount Etna challenge that assumption in that they contain high diversity assemblages of dasyurids dominated by prehistorically extinct species, including members of multiple previously unknown genera (Hocknull 2005, Hocknull et al. 2007, Cramb et al. 2009, Cramb & Hocknull 2010. ...
... Hocknull (2005) and Hocknull et al. (2007) described the geological, sedimentological and taphonomical settings for the fossil deposits yielding dasyurid remains in the Mount Etna region. Fossil dasyurids have been recovered from all known deposits at Mount Etna spanning approximately the last 500,000 years (500 ka). ...
Malleodectes? wentworthi, sp. nov. is a highly specialized durophagous marsupial from a Middle Miocene limestone cave deposit in the Riversleigh World Heritage area, northern Australia. It provides the first information regarding the lower dentition of malleodectids, an extinct family of dasyuromorphians. It is also the smallest durophagous member of Metatheria (marsupials and their stem relatives) known to date, with an estimated body mass of ∼70–90 g, an order of magnitude smaller than other known malleodectids (Malleodectes mirabilis and Ma. moenia ∼1 kg). As in other malleodectids, Ma.? wentworthi has a hypertrophied, dome-like premolar specialized for crushing hard foods. Tentative assignment to the genus Malleodectes is based on derived similarities of the premolar and molar dentition to those of larger species of Malleodectes (known only from upper dentitions), and occlusal compatibility. Quantitative morphofunctional analyses of dental indices and mandibular bending strength are congruent with the previously proposed hypothesis that malleodectids may have been uniquely specialized snail-eaters. Maximum parsimony phylogenetic analysis of a 173 morphological character dataset, with a molecular scaffold enforced, placed Ma.? wentworthi within Dasyuromorphia, in a basal polytomy with Dasyuridae and Mutpuracinus archibaldi, to the exclusion of Barinya wangala, Myrmecobiidae and Thylacinidae. Bayesian analysis of a total evidence dataset that combined morphological with nuclear and mitochondrial DNA sequence data places Ma.? wentworthi as a sister taxon to crown-clade Dasyuridae, although support for this relationship is weak.
... indicate geographic range reductions, as well as extinctions, of many species in response to increasingly arid conditions , Hocknull et al. 2007. Smallbodied vertebrates (here, informally termed 'microfauna' for species <5 kg in body weight) provide highly informative data for reconstructing local palaeoenvironmental conditions and for understanding ecological processes through time (Hadly 1996, Price 2012, Blois et al. 2010. ...
... For example, Brook et al. (2007, p. 562) stated: 'We should, therefore, predict that small mammals would have been much more likely to have been confined to restricted refugia and, thus, more vulnerable to extinction during periods of climatic stress than would the megafauna.' In north-eastern Australia, increasing aridity over the last 300,000 years impacted small mammals severely, with extinctions and extirpations linked directly to loss of preferred habitats (Price & Sobbe 2005, Hocknull et al. 2007, Cramb et al. 2018Price et al. 2020). Habitat loss and fragmentation affects biodiversity through, amongst several factors, a reduction in resource availability (Kupfer et al. 2006, Zanette et al. 2000. ...
... In the Queensland tropics, Hocknull et al. (2007Hocknull et al. ( , 2020 demonstrated that, concomitant with Pleistocene changes in climate, considerable extinctions of both micro-and megafauna occurred over the last 500 ka. In the central eastern Queensland area, these records were recovered from a large complex of caves formed in an isolated Devonian limestone massif situated approximately 23 km north of Rockhampton ( Fig. 1) in Darumbal Country. ...
Late Pleistocene to Holocene-aged microfaunal assemblages are rarely reported in Australia despite their critical importance for palaeoecological studies, as well as their bearing on the megafaunal extinction debate. Capricorn Caves, central-eastern Queensland, hosts three Late Pleistocene to Holocene deposits containing significant faunal records. Excavations were conducted on these deposits over several seasons, with analyses of recovered material ongoing. Here, we report interim results and explore their implications for our understanding of the microfaunal record of central eastern Queensland. Fern Chamber was previously dated using U-series to the Holocene (>7.6 ± 0.2 ka). Honeymoon Suite was dated to >6.4 ± 0.2 ka using U-series. However, new charcoal dates from the deposit span approximately 7.5–15.5 ka, although the association between charcoal and fauna is unresolved. The fauna is likely Holocene. Colosseum Chamber is the oldest of the deposits, and new single-grain luminescence ages and age-depth modelling suggest that the deposit likely spans MIS 1–4. We use abundant fragmentary rodent remains to examine palaeoenvironmental change over this period. Carbon and oxygen isotope analyses of rodent incisor fragments reveal broad diets within the rodent community, and significant differences in precipitation between glacial and interglacial conditions. Rodent long bone histological analyses indicate significant differences in bone metabolism at the family level between the MIS 3 and 2 samples, but not MIS 1. We suggest that these data support evidence for a mid-Holocene arid anomaly in the region, and increased aridity through the Holocene relative to the terminal Pleistocene. The sites contain at least 10 small mammal species either globally extinct or locally extirpated, including the Capricorn rabbit-rat (Conilurus capricornensis), the white-footed rabbit-rat (Conilurus albipes), the plains mouse (Pseudomys australis), Gould’s mouse (Pseudomys gouldii), Forrest’s mouse (Leggadina forresti), the long-tailed hopping mouse (Notomys longicaudatus), swamp rat (Rattus lutreolus), the white-tailed rat (Uromys caudimaculatus), the narrow-nosed planigale (Planigale tenuirostris), the Liverpool Plains striped bandicoot (Perameles fasciata), the Cape York brown bandicoot (Isoodon peninsulae), and the southern brown bandicoot (Isoodon obesulus). We also record significant range contractions for frogs (Philoria sp., Neobatrachus sp.) and earless dragons (Tympanocryptis sp.). This study demonstrates that significant changes in the microfaunal community of tropical Queensland occurred between the Late Pleistocene and the late Holocene. It also reinforces how poorly recorded native faunas are from the late Holocene through the historical period, to today. Such records underpin and are thus vital for modern biodiversity conservation efforts.
Julien Louys [j.louys@griffith.edu.au], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Jonathan Cramb [jonathan.cramb@qm.qld.gov.au], Queensland Museum, Brisbane, Australia; Kyle Ferguson [k.ferguson81@outlook.com.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Justine Kemp [j.kemp@griffith.edu.au], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Rachel Wood [rachel.wood@arch.ox.ac.uk], School of Archaeology and Anthropology, Australian National University, Canberra, Australia and Oxford Radiocarbon Accelerator Unit (ORAU), University of Oxford, Oxford, UK; Justyna J. Miszkiewicz [j.miszkiewicz@uq.edu.au], School of Social Science, University of Queensland, Brisbane, Australia and Naturalis Biodiversity Center, Leiden, the Netherlands; Nathalia R. Dias Guimarães [ndg0601@gmail.com], School of Archaeology and Anthropology, Australian National University, Canberra, Australia; Penny Higgins [pennilyn.higgins@gmail.com], EPOCH Isotopes, 6606 E Townline Road, Williamson, NY 14589, USA; Kenny J. Travouillon [Kenny.Travouillon@museum.wa.gov.au], Western Australian Museum, Perth, Australia; Scott A. Hocknull [scott.hocknull@qm.qld.gov.au], Geosciences, Queensland Museum, Brisbane, Australia; Gregory E. Webb [g.webb@uq.edu.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Gilbert J. Price [g.price1@uq.edu.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia.
... Australia is characterized by an exceptional herpetofaunal diversity (e.g., Pianka, 1989) and Pleistocene and Holocene fossil deposits, comprising herpetofaunal remains, are numerous throughout the continent (e.g., Lundelius, 1983;Bourne, 2000, 2009). However, the potential of Australian reptile and amphibian fossils for examining faunal change during this period has widely been neglected, presumably for the same reasons mentioned above (for exceptions see Smith, 1976Smith, , 1982Hope et al., 1977;Pledge, 1990;Price and Sobbe, 2005;Fraser and Wells, 2006;Hocknull et al., 2007;Hollenshead et al., 2011). Additionally, Australian paleoherpetologists are dealing with higher species diversity within fewer subfamilies in any single deposit; when family-or subfamily-level osteology-based identifications are more likely than genus or species level (Villa et al., 2017). ...
... The continent was subject to a gradual progressive aridification, which began about 700,000 years ago (Prescott et al., 2012), and intensified over the last 400-350 ka (e.g., Kershaw et al., 2003;Hope et al., 2004;Fujioka and Chappell, 2010). Little is known about changes in species composition or relative abundances of Australian herpetofaunal communities during this period (e.g., Hocknull, 2005;Hocknull et al., 2007) and statistical evidence of community change is almost entirely lacking. Hocknull et al. (2007) describe a mesic-adapted vertebrate fauna from tropical Queensland including reptiles and frogs, which was replaced about 280-205 ka (thousands of years ago) by an arid-adapted fauna. ...
... Little is known about changes in species composition or relative abundances of Australian herpetofaunal communities during this period (e.g., Hocknull, 2005;Hocknull et al., 2007) and statistical evidence of community change is almost entirely lacking. Hocknull et al. (2007) describe a mesic-adapted vertebrate fauna from tropical Queensland including reptiles and frogs, which was replaced about 280-205 ka (thousands of years ago) by an arid-adapted fauna. By the Holocene around 7 ka, mesic-adapted species were present again (Hocknull et al., 2007). ...
The Quaternary Period is characterized by dramatic global climatic changes. Quaternary fossil deposits, which can offer excellent stratigraphic resolution, provide a unique opportunity to understand how fauna respond to past environmental change. Here, we test if the herpetofauna of McEachern’s Deathtrap Cave, a late Pleistocene to Holocene pitfall trap deposit from Victoria, Australia, shows climate-related shifts in taxonomic relative abundance through time. During the last 14,000 years, southeastern Australia experienced pronounced periods of aridity, while temperatures remained relatively stable. We show that the stratigraphic layers of this deposit are characterized by different relative abundances of reptile subfamilies, and that changes in subfamily abundance between layers correlate with known shifts to aridity, based on the percentage of C4 grasses present in the region. We further identify 13 lizard morphotypes from the fossil deposit and compare this diversity with the present-day lizard fauna. Our analyses indicate that gradual changes in community structure, which are typically observed in southeastern Australian vertebrate communities during the Pleistocene–Holocene transition, can partly be explained by changing aridity. These findings represent an important contribution to understanding Quaternary community change in Australia, particularly because evidence of faunal succession of reptile and amphibian communities in Victoria is lacking. Our results further demonstrate the utility of the Australian herpetofaunal fossil record for detecting community responses to past climate change on relatively shallow timescales and at higher levels of taxonomic identification.
... Despite the presence of murines in Sahul since at least 4.18 Ma (Piper et al., 2006), published reports of fossil Uromys are almost all restricted to the Late Pleistocene and Holocene (e.g., O'Connor et al., 2002;Aplin et al., 1999). The exception is Hocknull (2005), who reported a large Mosaic-tailed Rat from the Mount Etna caves, which was later found to be of Middle Pleistocene age (Hocknull et al., 2007). This taxon is here described as Uromys aplini sp. ...
... Fossil deposits from Mount Etna were described initially by Hocknull (2005) with biocorrelation of these faunas suggesting a Pliocene age. Subsequent radiometric dating of flowstones associated with the fauna demonstrated, however, that these deposits were in fact Pleistocene in age and restricted to the Middle Pleistocene (Hocknull et al., 2007). Additional sites, descriptions, and dating assessments were also undertaken and available in Hocknull (2009). ...
... At Mount Etna, Middle Pleistocene faunal assemblages dated to >500 ka to ≥280 ka are interpreted as having occupied closed rainforest palaeoenvironments (QML1311H, QML1313) including taxa or lineages now only found in rainforests of northern Queensland and New Guinea (Hocknull, 2005;Hocknull et al., 2007;Price & Hocknull, 2011;Cramb & Hocknull, 2010). A younger Middle Pleistocene fauna (QML1312) dated to 205-170 ka is interpreted as having occupied a xeric environment and includes species or lineages found in arid habitats today. ...
The first fossil species of Uromys (Giant Naked-tailed Rats) is described, as well as the southern-most records of the genus based on palaeontological data. Uromys aplini sp. nov. lived during the Middle Pleistocene in the area around Mount Etna, eastern central Queensland, but was probably driven extinct by climate-mediated habitat loss sometime after 205 ka but before c. 90 ka. A second species, the extant U. caudimaculatus, occurred in the area during the Late Pleistocene, but became locally extinct prior to the Last Glacial Maximum. These fossils indicate an unexpectedly high diversity of species of Uromys in Australia, suggesting a long occupation of the continent. Phylogenetic analysis places U. aplini together with other species of Uromys endemic to Australia, at the base of the radiation of the genus. This may indicate that the initial diversification of Uromys occurred in Australia rather than New Guinea, as has previously been thought. These new Quaternary records of Uromys occur approximately 550 km south of the southern-most modern record for the genus, indicating that Uromys was able to cross the southern St Lawrence biogeographic barrier, possibly twice during the Pleistocene.
... Modern Australian ecosystems emerged during the Quaternary under a backdrop of major fluctuations in atmospheric carbon dioxide concentration, sea levels, and temperature, with a long-term trend towards progressively drier climates (Martin, 2006;Kershaw et al., 2003;Price, 2013). The period was marked not only by significant evolutionary events, but also major extinctions and geographic range shifts of many flora and fauna (e.g., Kershaw, 1994;Jordan et al., 1995;Reed & Bourne, 2000Hocknull et al., 2007;Prideaux et al., 2007;Price, 2012;Black et al., 2014). Today, at a time of widespread awareness over detrimental anthropogenic and climatic impacts on Australian ecosystems, it has become critical to understand the history of ecosystem origins and responses to similar past events. ...
... Areas such as the Darling Downs (southeast Queensland) and Mt Etna (central eastern Queensland), for example, have produced some of the most extensive records of Quaternary vertebrates north of the Queensland-New South Wales border. There, records show waves of extinction of both megafauna and micro-fauna (e.g., rodents, bandicoots) alongside progressive decreases in precipitation and expansion of more open habitats through the late Quaternary (Hocknull, 2005a;Hocknull et al., 2007;Cramb & Hocknull, 2010a;Price & Hocknull, 2011;Price et al., 2009;Price & Sobbe, 2005;Price & Webb, 2006;Price et al., 2015). While some Quaternary vertebrate fossils have been recovered from northern Australia (e.g., Archer et al ., 1978;Molnar, 1981;Klinkhammer & Godthelp, 2015;Cramb et al., 2018), the records remain patchy, are mostly undated, and are usually one-off collections or reports of single species. ...
... Their presence at Broken River during both the penultimate glacial cycle and early Holocene hints at an expanded arid zone during those times. Indeed, similar expansions of the arid zone towards the coastline have been inferred based on vertebrate-rich deposits from elsewhere such as Mt Etna (Hocknull et al., 2007), although the climate event recorded in those deposits occurred before 170 ka. ...
Two new fossil deposits from caves of the Broken River area, northeast Queensland, provide the first regional records of vertebrate species turnover and extinction through the late Quaternary. Fossil assemblages from Big Ho and Beehive Caves are dominated by small-bodied vertebrates, especially mammals. They represent owl roost deposits, although limited presence of larger-bodied taxa such as macropodids may be the result of occasional pitfall trapping. U-series dating demonstrates that Big Ho dates to the penultimate glacial cycle (c. 165 ka) and Beehive to the early Holocene (c. 8.5 ka). A total
of 34 mammalian taxa were identified; within the two deposits, seven taxa are unique to Big Ho and another seven are found only in Beehive. The deposits also preserve five extinct fossil taxa (bandicoots and rodents) that add to a growing list of small-bodied species known to have suffered extinction in the late Quaternary. The deposits further yield the remains of four species of bandicoots and rodents (Chaeropus yirratji, Notomys longicaudatus, Conilurus albipes, and Pseudomys gouldii) that suffered extinction post-
European colonization. These new fossil records represent significant increases in the known geographic and temporal range of several species and begin to fill an important gap in our understanding of the faunal history of tropical northeast Australia.
... Regardless of the prominent role climate plays, the global dispersal of Homo sapiens since the Middle Pleistocene (Grove, 2015;Hublin et al., 2017;Manzi, 2011;Richter et al., 2017;Wroe et al., 2004), likely had an accelerating effect on megafaunal extinctions where humans were invasive species. This is the case in the Americas, Madagascar, and especially in the insular Asia-Pacific, where the influence of (anatomically modern) humans (AMH) on megafaunal extinctions is part of an ongoing debate (Allen & O'Connell, 2014;Brook et al., 2013;Hocknull et al., 2007Hocknull et al., , 2020Johnson et al., 2016;Prideaux et al., 2007;Rule et al., 2012;Van der Kaars et al., 2017;Wroe et al., 2004Wroe et al., , 2013a2013b). Africa, Europe and western Asia suffered relatively lower losses probably due to co-evolution of hominins with endemic megafauna (Barnosky et al., 2004;Barnosky, 2008;Faith et al., 2018;Wroe et al., 2004). ...
... Especially in Australia, extensive dating research has been performed the last two decades which provided insights in the Late Pleistocene climate versus human-driven megafaunal extinction debate (Allen & O'Connell, 2014;Brook et al., 2013;Hocknull et al., 2007Hocknull et al., , 2020Johnson et al., 2016;Prideaux et al., 2007;Rule et al., 2012;Van der Kaars et al., 2017;Wroe et al., 2004Wroe et al., , 2013a2013b). Radiocarbon AMS dating has been successfully applied to marsupials like giant wombats, echidnas, tapirs, marsupial lions and giant kangaroos (Gillespie et al., 2012;Prideaux et al., 2009;Wroe et al., 2013a). ...
... U-series and coupled ESR/U-series dating have been applied to date the first record of Sahulian tropical rainforest taxa that became extinct due to increased aridity in the Middle Pleistocene (Hocknull et al., 2007(Hocknull et al., , 2020, as well as the first evidence of migratory behaviour in marsupials, based on the largest marsupial known to have existed on Earth, Diprotodon optatum (Price et al., 2017). ESR applications include dating of multiple Diprotodon-bearing sites (Grün et al., 2008), multiple Sthenurine kangaroos (Fraser and Wells, 2006) as well as the largest lizard known to have lived: the monstrous 'megalania' Varanus priscus, that co-existed with Homo sapiens (Price et al., 2015). ...
Since the 1980's, micro-analysis techniques applied to worldwide extinctions of Quaternary megafauna have resulted in revolutionary insights. However, in the Asia-Pacific, the infrastructure facilitating micro-analyses is still relatively limited. In this review, the potential of micro-analytical research applied to iconic megafauna will be discussed and evaluated. To address the imbalance between hominin versus faunal focused research we highlight the lack of knowledge of some taxa, the extent of unexplored regions and specific underutilised techniques that are relevant to megafaunal sites. Increased exchange of techniques, facilities and ideas is recommended to bridge the gap with Euro-American regions. This could provide a toolbox for conservation of modern megafauna across the Asia-Pacific to ensure these do not succumb to the same fate as mammoths, megalanias and other megabeasts.
... T he Pleistocene megafauna of Sahul are defined here as nonmarine vertebrates that exceed a mass of~40-44 kg 1 , comprising giant species of birds, reptiles and marsupials. They have vastly different phylogenetic histories 2 , occupying a diverse range of habitats [3][4][5] and reaching maximal body size by the Upper Pleistocene 6-8 (126,000-11,700 years ago (ka)). In the context of this work we do not consider unusually large-bodied taxa with a mass <40 kg as megafauna, but acknowledge that many species <40 kg also suffered extinction during the Pleistocene 9, 10 . ...
... Our understanding of the local and regional impacts of environmental deterioration during MIS 3 on megafauna in northern Sahul must also be considered within the context of much longer-term hydroclimate deterioration [70][71][72][73][74] and vegetation change 23,70,75 that was underway since the Middle Pleistocene, well before human occupation. These earlier changes have been implicated in major faunal 4 and floral 23 turnovers in northeast Australia, and yet similar turnovers are not recorded in southern Australian sites spanning similar timeframes 5,76 . Therefore the timing of environmental deterioration and the subsequent responses of fauna and flora differ between regions of Sahul, and have done so across much of the Quaternary. ...
... OSL core samples were collected by QM in 2009, 2011, 2015 and 2016 using extraction techniques and methodologies provided by GU laboratory and through best practice literature (see Supplementary Note 5). This included choosing sampling localities that (1) were freshly exposed through excavation into cohesive sedimentary matrix; (2) avoided areas showing sediment introduction via recent or old sediment cracking; (3) entirely avoided unconformities, major lithological boundaries and complex sedimentary matrices; (4) were positioned at least 20-30 cm below the exposed ground surface to avoid inaccuracies in gamma dose rates determined using ex situ (laboratory-based) dosimetry techniques. Sediment samples were taken from above and below each core at a radius of between 15 and 20 cm for sedimentological, high-resolution gamma spectrometry (HRGS) and water content assessments. ...
Explanations for the Upper Pleistocene extinction of megafauna from Sahul (Australia and New Guinea) remain unresolved. Extinction hypotheses have advanced climate or human-driven scenarios, in spite of over three quarters of Sahul lacking reliable biogeographic or chronologic data. Here we present new megafauna from north-eastern Australia that suffered extinction sometime after 40,100 (±1700) years ago. Megafauna fossils preserved alongside leaves, seeds, pollen and insects, indicate a sclerophyllous forest with heathy understorey that was home to aquatic and terrestrial carnivorous reptiles and megaherbivores, including the world’s largest kangaroo. Megafauna species diversity is greater compared to southern sites of similar age, which is contrary to expectations if extinctions followed proposed migration routes for people across Sahul. Our results do not support rapid or synchronous human-mediated continental-wide extinction, or the proposed timing of peak extinction events. Instead, megafauna extinctions coincide with regionally staggered spatio-temporal deterioration in hydroclimate coupled with sustained environmental change. The causes of the Upper Pleistocene megafauna extinction in Australia and New Guinea are debated, but fossil data are lacking for much of this region. Here, Hocknull and colleagues report a new, diverse megafauna assemblage from north-eastern Australia that persisted until ~40,000 years ago.
... The earliest records come from the Early Pleistocene Riversleigh World Heritage Area, northwestern Queensland (Klinkhamer & Godthelp, 2015) and Fisherman's Cliff fossil deposits in southern New South Wales (Crabb, 1977;Breed & Ford, 2007). Middle Pleistocene reports include Hocknull (2005;2009) and Hocknull et al. (2007) from cave deposits at Mt. Etna, central Queensland. Recent owl roost deposits in central Australia commonly contain the skeletal and dental remains of L. forresti (e.g. ...
... Etna region have come from numerous limestone cave deposits, located on Mt. Etna, the adjacent Limestone Ridge and nearby Olsen's Cave (Hocknull, 2005;Hocknull et al., 2007;Hocknull, 2009;Price & Piper, 2009;Cramb, Hocknull & Webb, 2009;Cramb & Hocknull, 2010a;Price et al., 2015). The majority of the fossil-rich deposits at Mt. Etna were initially exposed as a result of limestone mining activities on the western side of Mt. ...
... Uranium-thorium dating places the majority of deposits in the area within the last 500 ka, with some (e.g., Olsen's Cave) as recent as the late Holocene ( Hocknull et al., 2007;Price et al., 2015). The older deposits in the area (>500-280 ka BP) contain numerous species interpreted as indicative of a closed rainforest palaeoenvironment, while deposits dated to <250 ka BP mostly contain taxa that are more indicative of open, xeric habitats (Hocknull, 2005;Hocknull et al., 2007). ...
The genus Leggadina (colloquially known as ‘short-tailed mice’) is a common component of Quaternary faunas of northeastern Australia. They represent a member of the Australian old endemic murid radiation that arrived on the continent sometime during the late Cenozoic. Here we describe two new species of extinct Leggadina from Quaternary cave deposits as well as additional material of the extinct Leggadina macrodonta . Leggadina irvini sp. nov. recovered from Middle-Upper (late) Pleistocene cave deposits near Chillagoe, northeastern Queensland, is the biggest member of the genus, being substantially larger than any other species so far described. Leggadina webbi sp. nov. from Middle Pleistocene cave deposits at Mount Etna, central eastern Queensland, shares features with the oldest species of the genus, the Early Pleistocene L. gregoriensis . Based on the current palaeoecological interpretation of the type locality, L. webbi , represents the only member of the genus that inhabited rainforest. The succession of Leggadina species through the late Quaternary suggests an ecological replacement of the extinct large-bodied L. irvini with the extant, small-bodied L. lakedownesis at Chillagoe. At Mt. Etna, the extinct rainforest species L. webbi is replaced with the extant xeric-adapted L. forresti during the latest Middle Pleistocene. This replacement is associated with a mid-Pleistocene shift towards progressive intensifying seasonal and arid climates. Our study adds to the growing list of small-bodied faunal extinctions during the late Quaternary of northern Australia.
... Their distribution within Australia appears relictual, with two species (D. lumholtzi, D. bennettianus) confined to the Wet Tropics, a small area of coastal northeast Qld (Fig. 1) from 0 to 1600 m above sea level (a.s.l.) (Flannery et al., 1996;Johnson, 2003). However, a diversity of fossil tree-kangaroos (Dendrolagus, and the extinct Bohra) are more widely distributed in eastern and southern Australia in a variety of forest and woodland habitats (Flannery and Archer, 1984;Flannery et al., 1992aFlannery et al., , 1992bFlannery and Szalay, 1982;Hocknull et al., 2007;Warburton, 2008, 2009). Although the long-term decline in tree-kangaroo diversity and distribution within Australia has been linked to the continent's increasing aridity and the associated contraction of its wet forests (Flannery et al., 1996;Hocknull et al., 2007), the discovery of fossil tree-kangaroos in a semi-arid woodland fauna forces a reassessment of this hypothesis (Prideaux et al., 2007). ...
... However, a diversity of fossil tree-kangaroos (Dendrolagus, and the extinct Bohra) are more widely distributed in eastern and southern Australia in a variety of forest and woodland habitats (Flannery and Archer, 1984;Flannery et al., 1992aFlannery et al., , 1992bFlannery and Szalay, 1982;Hocknull et al., 2007;Warburton, 2008, 2009). Although the long-term decline in tree-kangaroo diversity and distribution within Australia has been linked to the continent's increasing aridity and the associated contraction of its wet forests (Flannery et al., 1996;Hocknull et al., 2007), the discovery of fossil tree-kangaroos in a semi-arid woodland fauna forces a reassessment of this hypothesis (Prideaux et al., 2007). By contrast, in New Guinea tree-kangaroos are widespread throughout the island's forests from 0 to 4,200 m a.s.l (Fig. 1). ...
... Fossils of the now extinct closely related tree-kangaroo genus Bohra date from the late Pliocene (Prideaux and Warburton, 2010), but the divergence between tree-kangaroo genera must predate the differentiation within Dendrolagus and so appears likely to have occurred earlier in the late Miocene. Although the fossil record of tree-kangaroos is still sparse (Hocknull et al., 2007;Prideaux and Warburton, 2010) it does document a diverse and widespread treekangaroo fauna in Australia that is now extinct and so is unrepresented in our phylogenetic analysis. If considered in isolation, our phylogenetic analysis could be interpreted as indicating a lack of early diversification within Australia but this is incompatible with the fossil data. ...
Amongst the Australasian kangaroos and wallabies (Macropodidae) one anomalous genus, the tree-kangaroos, Dendrolagus, has secondarily returned to arboreality. Modern tree-kangaroos are confined to the wet tropical forests of north Queensland, Australia (2 species) and New Guinea (8 species). Due to their behavior, distribution and habitat most species are poorly known and our understanding of the evolutionary history and systematics of the genus is limited and controversial. We obtained tissue samples from 36 individual Dendrolagus including representatives from 14 of the 17 currently recognised or proposed subspecies and generated DNA sequence data from 3 mitochondrial (3116 bp) and 5 nuclear (4097 bp) loci. Phylogenetic analysis of these multi-locus data resolved long-standing questions regarding inter-relationships within Dendrolagus. The presence of a paraphyletic ancestral long-footed and derived monophyletic short-footed group was confirmed. Six major lineages were identified: one in Australia (D. lumholtzi, D. bennettianus) and five in New Guinea (D. inustus, D. ursinus, a Goodfellow's group, D. mbaiso and a Doria's group). Two major episodes of diversification within Dendrolagus were identified: the first during the late Miocene/early Pliocene associated with orogenic processes in New Guinea and the second mostly during the early Pleistocene associated with the intensification of climatic cycling. All sampled subspecies showed high levels of genetic divergence and currently recognized species within both the Doria's and Goodfellow's groups were paraphyletic indicating that adjustments to current taxonomy are warranted.
... It appears likely, therefore, that rainforest species residing in Australia and New Guinea have been separated for considerably longer than previously thought (Westerman et al. 2001;Hocknull et al. 2007;Norman et al. 2007;Macqueen et al. 2010). If green pythons have been present in Australia for 250 000 years, their absence from the rainforests of the Lockerbie Scrub and Jardine River is because these rainforests disappeared during the glacial periods of the Pleistocene. ...
... Unlike the Iron-McIlwraith Range region, the Lockerbie Scrub and Jardine River catchment areas have relatively low topography and probably did not act as moist refugia during times of rainforest contraction (Webb and Tracy 1981). This fits with the findings of other studies, which show that Pleistocene rainforest contraction into moist refugia has resulted in the vicariance and extinction of other rainforest taxa in north Queensland (Dodson 1989;Schneider and Moritz 1999;Hocknull et al. 2007). The absence of green pythons in the Lockerbie Scrub and Jardine River Catchment is consistent with that of other rainforest-dependant fauna in Cape York (Legge et al. 2004). ...
The green python (Morelia viridis) is an iconic snake species highly sought after in the pet trade and is the target of illegal collection. Despite their popularity, some important ecological attributes of green pythons remain unknown, making their effective conservation management difficult. Detection-only surveys were conducted throughout the potential range of the green python in Australia, and intensive mark-recapture surveys were conducted in the areas where there have been previous records. In total, 298 green pythons were located in the Iron, McIlwraith and Kawadji-Ngaachi Ranges of Cape York, distributed over an estimated area of 2289 km 2 , where they frequented rainforest habitats and adjacent vine thickets. They were not found in the Lockerbie Scrub or Jardine River Catchment, despite anecdotal records. Green python density was estimated to be 540 km-2 in the Iron Range and 200 km-2 in the McIlwraith Range, where the percentages of adults captured were 56% and 83%, respectively. The differences between abundance and population demographics in the Iron and McIlwraith ranges may be due to differences in prey abundance and the impacts of collection. The results of this study provide baseline data to conservation managers and policy makers for the future conservation management of this species in Australia.
... Quaternary.-It is often assumed that only the megafauna went extinct in Australia during the Pleistocene and Holocene, but there is evidence that a number of small mammals also went extinct during this period. Two species of dasyurids, Antechinus yammal and A. yuna from the middle Pleistocene of Mount Etna in central Queensland, appear to have gone extinct (Cramb and Hocknull 2010) along with the disappearance of the rainforest in the region (Hocknull et al. 2007). Indeed many elements of the now-extinct rainforest marsupial fauna that occurred at Mount Etna during the middle Pleistocene show affinities with the modern New Guinea fauna rather than north Queensland (Hocknull 2005;Hocknull et al. 2007). ...
... Two species of dasyurids, Antechinus yammal and A. yuna from the middle Pleistocene of Mount Etna in central Queensland, appear to have gone extinct (Cramb and Hocknull 2010) along with the disappearance of the rainforest in the region (Hocknull et al. 2007). Indeed many elements of the now-extinct rainforest marsupial fauna that occurred at Mount Etna during the middle Pleistocene show affinities with the modern New Guinea fauna rather than north Queensland (Hocknull 2005;Hocknull et al. 2007). Intriguingly, a Pleistocene koala, Invictokoala monticola, described from Mount Etna (Price and Hocknull 2011), appears more closely related to late Oligocene koalas than to the modern species, suggesting the existence of a prolonged ghost lineage that is now extinct. ...
Marsupials and their fossil relatives, which collectively comprise Metatheria, have been of scientific interest for centuries, with many aspects of their evolution and systematics subject to intense research and debate. Here, we review progress over the last 25 years, which has included the description of many new species (modern and fossil), and major improvements in understanding of their phylogenetic relationships, as well as the overall evolutionary history and biogeography of Marsupialia (crown-clade) and Metatheria (total-clade). Significant advances have included the deployment of increasingly sophisticated molecular, morphological, and total evidence analyses, which have resolved most previously disputed relationships among and within the modern marsupial orders. A broad systematic consensus is now emerging, although several major areas of contention remain, particularly among fossil metatherians. New modern species continue to be described at an impressive rate, with almost 50 named in the last 25 years, and many more await discovery. There has also been an explosion in the discovery and description of fossil marsupials and non-marsupial metatherians (~270 species), principally from Australasia and the Americas but also from Antarctica, Europe, and Asia. Most are represented by dental specimens only, but some consist of complete and well-preserved material, which has led to major improvements in our understanding of the evolution of cranial and postcranial morphology. Improvements in the fossil record and advances in methods for inferring divergence times have helped clarify when and where key events occurred in metatherian evolution, and the patterns of subclade diversification. We also have improved understanding of biogeographical relationships among metatherians on different landmasses. Despite enormous progress, numerous key uncertainties remain due to major gaps in the fossil record (e.g., Antarctica, Late Cretaceous, and early Paleogene of Australia) and a comparative lack of studies that directly combine molecular and fossil data. Future advances will largely depend on improvements in the fossil record and studies that better integrate neontological and paleontological evidence. Los marsupiales y sus parientes fósiles, que en conjunto forman el grupo Metatheria, han sido de interés científico durante siglos, con muchos aspectos de su evolución y sistemática sujetos a intensas investigaciones y debates. Aquí se resumen los avances alcanzados durante los últimos 25 años, los cuales incluyen la descripción de muchas especies nuevas (tanto fósiles como actuales), una mayor comprensión de relaciones filogenéticas, y también la historia general evolutiva y biogeográfica de Marsupialia (clado corona) y Metatheria (clado completo). Los mayores avances han incluido el uso de análisis moleculares, morfológicos y de evidencia total que son cada vez más sofisticados. Dichos avances ya han resuelto muchas de las relaciones anteriormente disputadas fuera y dentro de los ordenes de marsupiales actuales. Actualmente está surgiendo un amplio consenso general, a pesar de que aún quedan varias áreas importantes de discusión. Se continúa describiendo especies nuevas actuales a una velocidad impresionante, con casi 50 nombradas en los últimos 25 años, y muchas más esperan a ser descubiertas. También ha habido una explosión en el descubrimiento y descripción de especies fósiles de marsupiales y metaterios no-marsupiales (~270 especies), principalmente de Australasia y las Américas, pero
... In addition, we observed barrier effects across the historically dry Black Mountain Corridor in AWT (Costion et al., 2016;Edwards et al., 2017), which is expected if human influence was minimal, since faunal-mediated and passive dispersal is inhibited by habitat barriers. These regional differences in dispersal cannot be attributed to different faunal assemblages, since there are fewer extant vertebrates in SEQ than the AWT (Hocknull et al., 2007), and local dispersal by sulphur-crested cockatoos has been observed in both regions . In addition, we did not find evidence of serial founder effects in SEQ that can be expected of rapid faunal- & Sebbenn, 2007), and given the large size of A. angustifolia pollen grains (Sousa & Hattemer, 2003), dispersion capacity is limited within dense forests (Bittencourt & Sebbenn, 2007;Kling & Ackerly, 2021). ...
Retracing past anthropogenic dispersal of culturally important taxa offers insights to the biogeographic history of species, as well as the history of the people who interacted with them. Bunya Pine ( Araucaria bidwillii Hook.) is a culturally and spiritually significant conifer tree for several Indigenous groups in eastern Australia. Sharing the edible nuts and attending Bunya gatherings is an important way for these groups to maintain their cultural connections and it has been hypothesized that prior to European colonization, Indigenous Peoples facilitated the dispersal of Bunya Pine as part of these ancient traditions.
We used ethnohistorical information on the use of Bunya Pine by Indigenous Peoples to interpret genomic patterns within and between disjunct distributions of Bunya Pine.
We found signatures of long‐term isolation within the Australian Wet Tropics (AWT) and extensive gene flow within southeast Queensland (SEQ) that does not fit models of faunal or passive dispersal. Within SEQ, we found greater population structure amongst sites known to pre‐date European colonization, than when colonial‐era planted sites were included in our analyses, suggesting that pre‐colonial translocation was sporadic or localized rather than systematic and widespread. Increased Indigenous translocations in conjunction with plantings by European settlers appears to have erased the natural pre‐colonial population structure of SEQ Bunya Pine. Our stairway plot models suggest sharp population decline of SEQ Bunya Pine in the early and late Pleistocene, though we did not find evidence that anthropogenic dispersal facilitated effective population size growth of the species in the Holocene.
We concluded that pre‐colonial translocation of SEQ Bunya Pine was likely restricted by kinship‐based custodial rights, and that when Indigenous Peoples were displaced by European settlers, translocation was intensified to maintain cultural connectivity. This study is an example of how Indigenous Australian groups adapt plant management strategies to meet socio‐cultural needs and demonstrates the potential for plant genomics to supplement Indigenous Biocultural Knowledge that has been impacted by colonial dispossession.
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... Enamel powder for bulk analysis was obtained using a diamond-tipped drill. All enamel powder was pretreated following established protocols 23,61 . Following reaction with 100% phosphoric acid, gases evolved from the samples were analysed for their stable carbon and oxygen isotopic measurements using a Thermo Gas Bench 2 connected to a Thermo Delta V Advantage Mass Spectrometer at the Max Planck Institute for Geoanthropology (formerly for the Science of Human History). ...
The largest ever primate and one of the largest of the southeast Asian megafauna, Gigantopithecus blacki¹, persisted in China from about 2.0 million years until the late middle Pleistocene when it became extinct2–4. Its demise is enigmatic considering that it was one of the few Asian great apes to go extinct in the last 2.6 million years, whereas others, including orangutan, survived until the present⁵. The cause of the disappearance of G. blacki remains unresolved but could shed light on primate resilience and the fate of megafauna in this region⁶. Here we applied three multidisciplinary analyses—timing, past environments and behaviour—to 22 caves in southern China. We used 157 radiometric ages from six dating techniques to establish a timeline for the demise of G. blacki. We show that from 2.3 million years ago the environment was a mosaic of forests and grasses, providing ideal conditions for thriving G. blacki populations. However, just before and during the extinction window between 295,000 and 215,000 years ago there was enhanced environmental variability from increased seasonality, which caused changes in plant communities and an increase in open forest environments. Although its close relative Pongo weidenreichi managed to adapt its dietary preferences and behaviour to this variability, G. blacki showed signs of chronic stress and dwindling populations. Ultimately its struggle to adapt led to the extinction of the greatest primate to ever inhabit the Earth.
... Cave deposits at Mount Etna (central Queensland) have yielded fossils that define a Middle Pleistocene rainforest paleoenvironment rich in vertebrate species (Hocknull et al. 2007). It is unclear whether this rainforest assemblage is typical of the region or represents a local refugium. ...
Australian cave sediments range from desert sands to tropical clays and glacial boulders, and contain deposits of bones, pollen and artefacts that can tell us a great deal about environmental and human histories of the areas surrounding the caves.
... The extensive quarrying at Mt Etna destroyed numerous caves but serendipitously exposed fossil deposits with a diverse fauna including molluscs, frogs, lizards, snakes, marsupials and rodents (Hocknull 2005). The oldest deposits (>280,000 years old) contain many rainforest species, but by *200,000 years ago, the fauna was dominated by species adapted to an open, arid environment (Hocknull et al. 2007). ...
Within north-eastern Australia, the northernmost karst areas, Mitchell–Palmer and Chillagoe, are characterised by spectacular serrated limestone towers. The towers are densely cavernous and contain over 1000 caves, which are mostly joint-controlled mazes of rift passages developed on one level, with entrances are on the sides of towers. Passages frequently connect upwards with grikes, so daylight chambers are common. The towers may have originated in the early Mesozoic, but development of the caves within the towers, as well as the surface karren features, occurred once the tropical monsoonal climate, with its pronounced wet and dry seasons, became established across northern Australia.
... Many vertebrate groups share extant taxa across New Guinea and northern Australia (e.g., Macqueen et al. 51 and Peñ alba et al. 65 ) and fossil evidence suggests there was even greater diversity of shared rainforest fauna until the middle Pleistocene. [66][67][68] While New Guinea and Australia have been distinct biogeographic regions for much of their history, and are modeled as such in our biogeographic analyses, during the Pleistocene they were repeatedly connected via the Arafura Shelf. These periods of connectivity have likely played an important role in facilitating biotic exchange between New Guinea and Australia; however, our biogeographic reconstruction emphasizes the lack of connectivity prior to 5 Ma. ...
Sahul unites the world’s largest and highest tropical island and the oldest and most arid continent on the backdrop of dynamic environmental conditions. Massive geological uplift in New Guinea is predicted to have acted as a species pump from the late Miocene onward, but the impact of this process on biogeography and diversification remains untested across Sahul as a whole. To address this, we reconstruct the assembly of a recent and diverse radiation of rodents (Murinae: Hydromyini) spanning New Guinea, Australia, and oceanic islands. Using phylogenomic data from 270 specimens, including many recently extinct and highly elusive species, we find that the orogeny and expansion of New Guinea opened ecological opportunity and triggered diversification across a continent. After a single over-water colonization from Asia ca. 8.5 Ma, ancestral Hydromyini were restricted to the tropical rainforest of proto-New Guinea for 3.5 million years. Following a shift in diversification coincident with the orogeny of New Guinea ca. 5 Ma and subsequent colonization of Australia, transitions between geographic regions (n = 24) and biomes (n = 34) become frequent. Recurrent over-water colonization between mainland and islands demonstrate how islands can play a substantial role in the assembly of continental fauna. Our results are consistent with a model of increased ecological opportunity across Sahul following major geological uplift in New Guinea ca. 5 Ma, with sustained diversification facilitated by over-water colonization from the Pleistocene to present. We show how geological processes, biome transitions, and over-water colonization collectively drove the diversification of an expansive continental radiation.
... It is also likely that dispersal limitations have played a key role in genetic structuring between F. australis populations. Now-extinct megafauna were once central to the dispersal of fleshy-fruited subtropical rainforest species [66]. However, given the combination of low genetic diversity, a lack of dispersal observations, and the clumped and fragmented distribution seen in extant species of Fontainea, gravity and hydrochory have been proposed as the contemporary mechanisms of diaspore transport for the genus [12]. ...
Fontainea is a plant genus with nine recognised species that occur across the tropical and subtropical rainforests of Australia, Papua New Guinea, New Caledonia, and Vanuatu. One of these species is cultivated commercially as the source of a cancer therapeutic, and several other species are under threat of extinction. Despite this, the phylogenetic relationships of the genus have not been explored. Our study assessed the phylogeny of seven Fontainea taxa from the Australian and Pacific Island complex using chloroplast DNA sequence data and reduced-representation genome sequencing. Maximum-likelihood and consensus network trees were used to infer the topology of phylogenetic relationships between species, which highlighted three distinct lineages and a number of sister species. Our results indicated that the geographically disjunct species Fontainea venosa and F. pancheri formed a sister group at the earliest position of divergence for the genus. The data also revealed that the vulnerable Fontainea australis and the critically endangered F. oraria form a sister subclade with evidence of some shared plastid genotypes. Generally, our phylogenetic reconstruction supports the modern taxonomical nomenclature. However, we suggest further accessions across several species may support improved genetic distinctions between the sister groups of Fontainea within the genus
... Posterior distributions of model parameters estimated under an ABC framework indicated that the partitioning of genetic diversity among extant groups of koalas could be best explained by admixture between the Queensland, Mid-Coast New South Wales and Southern Australia major genetic clusters, which appeared to have emerged near simultaneously following pronounced genetic bottlenecks >300 kya. While precise divergence times should be treated with caution, these data suggest that the demographic history of modern koalas has been heavily influenced by the mid-Brunhes transition (MBT) (~430-300 kya), a major climatic reorganisation that increased the amplitude of glacial-interglacial cycles, and drove progressive aridity across much of the Australian continent (Hocknull et al., 2007). The more pronounced climatic fluctuations of the middle-to late-Pleistocene are in turn hypothesised to have caused cyclical range expansions and contractions in many mesic taxa, which would be expected to present as divergent, geographically discreet lineages, as predicted by the refugia hypothesis (Byrne et al., 2011). ...
Climatic and evolutionary processes are inextricably linked to conservation. Avoiding extinction in rapidly changing environments often depends upon a species’ capacity to adapt in the face of extreme selective pressures. Here, we employed exon capture and high‐throughput next‐generation sequencing to investigate the mechanisms underlying population structure and adaptive genetic variation in the koala (Phascolarctos cinereus), an iconic Australian marsupial that represents a unique conservation challenge because it is not uniformly threatened across its range. An examination of 250 specimens representing 91 wild source locations revealed that five major genetic clusters currently exist on a continental scale. The initial divergence of these clusters appears to have been concordant with the Mid‐Brunhes Transition (∼ 430–300 kya), a major climatic reorganization that increased the amplitude of Pleistocene glacial‐interglacial cycles. While signatures of polygenic selection and environmental adaptation were detected, strong evidence for repeated, climate‐associated range contractions and demographic bottleneck events suggests that geographically isolated refugia may have played a more significant role in the survival of the koala through the Pleistocene glaciation than in situ adaptation. Consequently, the conservation of genome‐wide genetic variation must be aligned with the protection of core koala habitat to increase the resilience of threatened populations to accelerating anthropogenic threats. Finally, we propose that the five major genetic clusters identified in this study should be accounted for in future koala conservation efforts (e.g. guiding translocations), as existing management divisions in the states of Queensland and New South Wales do not reflect historic or contemporary population structure.
... Specialised large-fruit dispersers have been historically absent from NNSW and SEQ, and local dispersal rates are expected to be lower in the region [54,55]. Therefore, it is assumed that large fleshy fruit in southern forests have no means of long-distance dispersal except through human activity. ...
Over millennia, Indigenous peoples have dispersed the propagules of non-crop plants through trade, seasonal migration or attending ceremonies; and potentially increased the geographic range or abundance of many food species around the world. Genomic data can be used to reconstruct these histories. However, it can be difficult to disentangle anthropogenic from non-anthropogenic dispersal in long-lived non-crop species. We developed a genomic workflow that can be used to screen out species that show patterns consistent with faunal dispersal or long-term isolation, and identify species that carry dispersal signals of putative human influence. We used genotyping-by-sequencing (DArTseq) and whole-plastid sequencing (SKIMseq) to identify nuclear and chloroplast Single Nucleotide Polymorphisms in east Australian rainforest trees (4 families, 7 genera, 15 species) with large (>30 mm) or small (<30 mm) edible fruit, either with or without a known history of use by Indigenous peoples. We employed standard population genetic analyses to test for four signals of dispersal using a limited and opportunistically acquired sample scheme. We expected different patterns for species that fall into one of three broadly described dispersal histories: (1) ongoing faunal dispersal, (2) post-megafauna isolation and (3) post-megafauna isolation followed by dispersal of putative human influence. We identified five large-fruited species that displayed strong population structure combined with signals of dispersal. We propose coalescent methods to investigate whether these genomic signals can be attributed to post-megafauna isolation and dispersal by Indigenous peoples.
... Large-fruited laurels of the subtropics may have been dispersed by these or similar species, or other extinct megafauna such as the herbivorous giant horned land turtle Ninjemys oweni (Woodward, 1888) that was described from a Pleistocene fossil deposit on the Darling Downs of Qld (Sterli 2015). The extinction of megafauna from subtropical eastern Australia is now thought to be relatively recent dating to the Quaternary, c. 280,000 years ago (Hocknull et al. 2007). The case of Endiandra compressa C.T.White (another laurel with large fruit) is the most convincing in this regard, as this species is known to be consumed by cassowaries in the northern tropical part of its distribution, but is rare and restricted to stream banks in the subtropical zone where this bird is absent. ...
Weber, L.C. & Forster, P.I. (2021). Endiandra wongawallanensis L.Weber (Lauraceae), a new species from southeast Queensland allied to E. floydii B.Hyland. Austrobaileya 11: 155-169. Analysis of morphological variation in plants previously classified as Endiandra floydii B.Hyland has revealed that two allopatric taxa are present. Endiandra floydii has a more restricted distribution than previously given and now appears to be only present in northeast New South Wales. The Queensland plants differ in a range of both vegetative and reproductive characters and are described here as the new species E. wongawallanensis L.Weber. It is endemic to a small area south of Beenleigh and north of Tallebudgera Creek. The new species is described with notes on distribution, habitat, dispersal ecology and conservation status. The biogeographic context for both species and the areas they occur in is discussed.
... This interpretation along with the new dates supports recent independent biochronological interpretations (Cramb et al., 2018) that suggest that the Floraville's assemblages are Quaternary, rather than Pliocene. It is pertinent to note that Floraville represents the first and hitherto only confirmed middle Pleistocene vertebrate fossil locality of the northern Australian tropics; this also demonstrates that the fossil assemblages are temporally coeval with the majority of vertebrate-bearing fossil deposits of the Mt Etna and Texas cave areas of eastern Australia (Hocknull et al., 2007;Price et al. 2009aPrice et al. , 2009b, and Naracoorte caves of southeastern Australia (Moriarty et al., 2000;Prideaux et al., 2007b;Macken et al., 2011). ...
The extinction of large-bodied terrestrial ‘megafauna’ during earlier phases of the Quaternary had a significant impact on the transforming structure of ecosystems. However, the causes of such losses remains difficult to determine in part because of a paucity of reliable geochronological information about the taxa involved. This is especially true for continents such as Australia where the majority of extinct species have never been dated using radiometric and/or luminescence methods. Here we add new understanding about the geochronology of the world's largest-ever marsupial, the giant wombat-like Diprotodon optatum, an iconic member of the large herbivore guild of Pleistocene Australia. We present 28 new direct U-series ages (dentine) and 10 luminescence ages (sediments) for D. optatum fossils from three sites in tropical north and subtropical eastern Australia. The luminescence ages lie close to saturation for the tropical northern site of Floraville and therefore indicate minimum ages, and sediments from Gowrie Creek in the Darling Downs were mixed and can only be stated as a likely age range. Nevertheless the results assist in our broader understanding of the timing of persistence of the species. Our results demonstrate that the species roamed the northern tropics at least until the mid-Pleistocene (ca. 420 ka). They likely remained widespread during Marine Isotope Stage 5 (ca. 110 ka) and were abundant on the Darling Downs of eastern Australia. The youngest of the new ages that we report (ca. 60 ka) are from Neds Gully on the Darling Downs, a catchment previously considered by some to contain among the last survivors of the now-extinct megafauna. The new dated record demonstrates that deposits of varying ages occur within the catchment. Consequently, existing species lists that treat Neds Gully as a single faunal assemblage are likely significantly time-averaged and overinflated in terms of palaeo-diversity.
... Thylacines co-existed with ancient tree-kangaroos of the genus Bohra (Flannery and Szalay 1982;Johnson and Wroe 2003;Prideaux and Warburton 2009) on the Nullarbor Plain (Curry et al. 2014), and show phylogenetic relationships with the Tasmanian devil (Attard et al. 2011). Tasmanian devils also seem to have coexisted with recent ancestors of LTKs (Bohra paulae, Flannery and Szalay 1982) because fossil remains of the genus Dendrolagus have been found in deposits in eastern and northern Australia (Hocknull et al. 2007) from the Pliocene and mid/late Pleistocene, and remains of the Tasmanian devil were widespread in mainland Australia (Calaby and White 1967;Horton 1977;Dawson 1982;Muirhead 1992;Dawson 2004). Although Tasmanian devils are terrestrial and specialised scavengers among living marsupials, they are also opportunistic hunters known to prey on mammals that may exceed their body mass (Guiler 1970). ...
The high extinction risk of Australian marsupials has been attributed to their failure to recognise novel predators, the application of inappropriate antipredator responses, and advanced hunting strategies of novel predators. This study is a preliminary attempt to explore whether the Lumholtz’ tree-kangaroo (Dendrolagus lumholtzi) (a) is able to recognise odour cues from different predators as threats, and (b) possesses predator-archetype specific antipredator responses. A small number of available captive tree-kangaroos were exposed to faecal odours from two extant predators of different archetypes (python, dingo), a regionally extinct predator which closely matches past terrestrial predators (Tasmanian devil), and a novel predator (domestic dog). Lavender oil was used as non-predator novel odour and water as control. Results suggest that all subjects associated the presented odours with a threat, albeit to different degrees, but did not display predator-archetype specific responses. It appears that this species applies an ancestral antipredator response of flight-on-the ground when encountering predators, including novel predators. Although the results need to be confirmed with more animals, further studies on the vulnerability of Australian prey to novel predators should take the ancestral history of Australian prey species into account.
... These bone fragments show similar levels of surface weathering and wind-blown sand abrasion. The proximity of the Eromanga and Northern Territory sites to the sand dunes of the Munga-Thirri Desert provides adequate mechanisms for sand abrasive conditions to be present especially throughout the intensified aridity of the late Quaternary (Hocknull et al., 2007;Hollands et al., 2006;Maroulis et al., 2007). In comparison, the dinosaur localities of Winton and Isisford to the north and east are distal to these dunes and probably did not experience this kind of abrasive surface weathering. ...
A new giant sauropod, Australotitan cooperensis gen. et sp. nov., represents the first record of dinosaurs from the southern-central Winton Formation of the Eromanga Basin, Australia. We estimate the type locality to be 270–300 m from the base of the Winton Formation and compare this to the semi-contemporaneous sauropod taxa, Diamantinasaurus matildae Hocknull et al., 2009, Wintonotitan wattsi Hocknull et al., 2009 and Savannasaurus elliottorum Poropat et al., 2016. The new titanosaurian is the largest dinosaur from Australia as represented by osteological remains and based on limb-size comparisons it reached a size similar to that of the giant titanosaurians from South America. Using 3-D surface scan models we compare features of the appendicular skeleton that differentiate Australotitan cooperensis gen. et sp. nov. as a new taxon. A key limitation to the study of sauropods is the inability to easily and directly compare specimens. Therefore, 3-D cybertypes have become a more standard way to undertake direct comparative assessments. Uncoloured, low resolution, and uncharacterized 3-D surface models can lead to misinterpretations, in particular identification of pre-, syn- and post-depositional distortion. We propose a method for identifying, documenting and illustrating these distortions directly onto the 3-D geometric surface of the models using a colour reference scheme. This new method is repeatable for researchers when observing and documenting specimens including taphonomic alterations and geometric differences. A detailed comparative and preliminary computational phylogenetic assessment supports a shared ancestry for all four Winton Formation taxa, albeit with limited statistical support. Palaeobiogeographical interpretations from these resultant phylogenetic hypotheses remain equivocal due to contrary Asian and South American relationships with the Australian taxa. Temporal and palaeoenvironmental differences between the northern and southern-central sauropod locations are considered to explain the taxonomic and morphological diversity of sauropods from the Winton Formation. Interpretations for this diversity are explored, including an eco-morphocline and/or chronocline across newly developed terrestrial environments as the basin fills.
... Taken together, the results for the five most recently diverging taxa highlight that although some components of the CEAR avifauna are relictual and diverged before the Plio-Pleistocene, most endemics are likely to stem from dynamic recent histories of Plio-Pleistocene range contraction. Indeed, fossil and genetic data provide complementary evidence of recent range contraction, isolation and fragmentation across central Queensland in rainforest or wet forest vertebrates (Nicholls & Austin, 2005;Hocknull et al., 2007;Macqueen et al., 2010;Irestedt et al., 2017) and plants (Sniderman & Jordan, 2011). Fig-parrots and catbirds are more diverse in New Guinea than in Australia. ...
Subtropical and temperate rainforests of Central Eastern Australia are some of the largest remaining fragments of their kind globally. The biota of these rainforests appears to comprise two broad biogeographical elements: a more ancient (Miocene or older) and typically upland temperate (‘Gondwanan’) element and a younger (Plio-Pleistocene) lowland tropical element. We present the first phylogenetic synthesis of the spatiotemporal origins for the eight bird taxa endemic to Central Eastern Australian Rainforests. At least five of these eight focal taxa show Plio-Pleistocene divergences from their respective northern sister taxa, consistent with origins driven by recent expansion and contraction of lowland rainforest. In contrast, two more strictly upland species, the rufous scrub-bird (Atrichornis rufescens) and the logrunner (Orthonyx temminckii), diverged from their nearest living relatives during the Miocene, suggesting potentially longer histories of persistence and more temperate origins. Finally, we did not recover reciprocal monophyly in mitogenomes from the two extant lyrebirds, Albert’s lyrebird (Menura alberti) and the superb lyrebird (Menura novaehollandiae). The disparate divergence ages recovered among all eight taxa are consistent with the biota of the Central Eastern Australian Rainforests comprising isolates either of younger age and tropical lowland origins or of older age and temperate upland origins.
... A study of fossil remains near the central Queensland coast (Mt. Etna) however, supports the presence of several species of tree kangaroos in what was then a tropical rainforest environment until around 280,000 years ago (Hocknull et al., 2007). At least one of these now extinct species was related to the New Guinea tree kangaroo form, suggesting a secondary invasion into Australia. ...
In this chapter, the present understanding of tree kangaroo diversity is summarized with a review of the origins and evolution of the group and their adaptations to a largely arboreal lifestyle. The 14 extant species of Dendrolagus (Macropodidae), confined to the continent of Australia and New Guinea, are each described and illustrated with details on their biogeography, the threats to their survival, and their current conservation status.
... Other examples of material scanned using our high-throughput method are shown in Fig. 4. Fossilized frog ilia and varanid osteoderms (bony deposits in the scales of some lizards) yielded excellent results following this protocol (Fig. 4a,b), with hundreds of 3D models generated for minimal time, money and effort. We also applied our system to larger mammalian specimens, for example fossilized rodent jaws from the Middle Pleistocene Mt Etna 42 . This material is larger and denser than the herpetological samples, requiring slightly different parameters for µCT scanning. ...
High-resolution X-ray microcomputed tomography, or microCT (μCT), enables the digital imaging of whole objects in three dimensions. The power of μCT to visualize internal features without disarticulation makes it particularly valuable for the study of museum collections, which house millions of physical specimens documenting the spatio-temporal patterns of life. Despite the potential for comparative analyses, most μCT studies include limited numbers of museum specimens, due to the challenges of digitizing numerous individuals within a project scope. Here we describe a method for high-throughput μCT scanning of hundreds of small (< 2 cm) specimens in a single container, followed by individual labelling and archival storage. We also explore the effects of various packing materials and multiple specimens per capsule to minimize sample movement that can degrade image quality, and hence μCT investment. We demonstrate this protocol on vertebrate fossils from Queensland Museum, Australia, as part of an effort to track community responses to climate change over evolutionary time. This system can be easily modified for other types of wet and dry material amenable to X-ray attenuation, including geological, botanical and zoological samples, providing greater access to large-scale phenotypic data and adding value to global collections.
... This resulted in the gradual restriction of rain forests to the Eastern coast of Australia, separated from more arid inland habitats by the great dividing range (Bell, Moritz, Moussalli, & Yeates, 2007;Kershaw, 1994;McGuigan, McDonald, Parris, & Moritz, 1998;Pope, Estoup, & Moritz, 2000;Schneider, Cunningham, & Moritz, 1998). Between 280 and 205 kya, decreased precipitation and more severe aridification were associated with major faunal turnover in rainforest taxa (Hocknull, Zhao, Feng, & Webb, 2007). ...
Population divergence and gene flow are key processes in evolution and ecology. Model‐based analysis of genome‐wide datasets allows discrimination between alternative scenarios for these processes even in non‐model taxa. We used two complementary approaches (one based on the blockwise site frequency spectrum (bSFS), the second on the Pairwise Sequentially Markovian Coalescent (PSMC)) to infer the divergence history of a fig wasp, Pleistodontes nigriventris. Pleistodontes nigriventris and its fig tree mutualist Ficus watkinsiana are restricted to rain forest patches along the eastern coast of Australia, and are separated into northern and southern populations by two dry forest corridors (the Burdekin and St. Lawrence Gaps). We generated whole genome sequence data for two haploid males per population and used the bSFS approach to infer the timing of divergence between northern and southern populations of P. nigriventris, and to discriminate between alternative isolation with migration (IM) and instantaneous admixture (ADM) models of post divergence gene flow. Pleistodontes nigriventris has low genetic diversity (π = 0.0008), to our knowledge one of the lowest estimates reported for a sexually reproducing arthropod. We find strongest support for an ADM model in which the two populations diverged ca. 196kya in the late Pleistocene, with almost 25% of northern lineages introduced from the south during an admixture event ca. 57kya. This divergence history is highly concordant with individual population demographies inferred from each pair of haploid males using PSMC. Our analysis illustrates the inferences possible with genome‐level data for small population samples of tiny, non‐model organisms and adds to a growing body of knowledge on the population structure of Australian rain forest taxa.
... At least one other open woodland taxon from eastern Queensland shows a signature of past shifts in population size (Irestedt et al., 2019). Evidence from vertebrate fossil deposits (Hocknull et al., 2007), palynogical series (Williams et al., 2006) and climate modelling (Shabani et al., 2019) also suggest that taxa associated with woodland or open forest biomes in eastern Australia have had dynamic histories of expansion and contraction through the Pleistocene. ...
... Other examples of material scanned using our high-throughput method are shown in Fig. 4. Fossilized frog ilia and varanid osteoderms (bony deposits in the scales of some lizards) yielded excellent results following this protocol (Fig. 4a,b), with hundreds of 3D models generated for minimal time, money and effort. We also applied our system to larger mammalian specimens, for example fossilized rodent jaws from the Middle Pleistocene Mt Etna 42 . This material is larger and denser than the herpetological samples, requiring slightly different parameters for µCT scanning. ...
High-resolution X-ray microcomputed tomography, or microCT (μCT), enables the digital imaging of whole objects in three dimensions. The power of μCT to visualise internal features without disarticulation makes it particularly valuable for the study of museum collections, which house millions of physical specimens documenting the spatio-temporal patterns of life. Despite its potential for comparative analyses, most μCT studies include limited numbers of museum specimens, due to the challenges of digitising numerous individuals within a project scope. Here we describe a method for high-throughput μCT scanning of hundreds of small (< 2 cm) specimens in a single container, followed by individual labelling and archival storage. We also explore the effects of various packing materials and multiple specimens per capsule to minimize sample movement that can degrade image quality, and hence μCT investment. We demonstrate this protocol on vertebrate fossils from Queensland Museum, Australia, as part of an effort to track community responses to climate change over evolutionary time. This system can be easily modified for other types of wet and dry material amenable to X-ray attenuation, including geological, botanical and zoological samples, providing greater access to large-scale phenotypic data and adding value to global collections.
... This aridification extended to the east coast by ca. 300 ka (Hocknull et al., 2007), so all of eastern and central Australia was arid by 300 ka. Travertine deposition within the 285-240 ka period (see Fig. 7 (Nanson et al., 2008) but if travertine deposition really is related to moister climates, older travertines should be more widely preserved. ...
... , Aplin et al. (1993Aplin et al. ( , 1999Aplin et al. ( , 2010, Beck (2017), Bowyer et al. (2003), Byrne et al. (2011), Colgan andFlannery (1993), De Vis (1887-1888), Eldridge and Coulson (2015), Eldridge et al. (2018), Flannery (1993, Flannery and Archer (1984), Flannery and Boeadi (1995), Flannery and Seri (1990a, 1990b), Flannery and Szalay (1982), Flannery et al. (1983, 1992, 1996), Förster and Rothschild (1907, , Groves (1982Groves ( , 2005, Heinsohn (2003), Helgen (2007aHelgen ( , 2007b, Helgen and Flannery (2004), Helgen et al. (2010), Hocknull et al. (2007), Hume et al. (1989), Husson (1955), Irestedt et al. (2009Irestedt et al. ( , 2015, Joseph et al. (2014), Kawei (1989), Kirsch et al. (1990Kirsch et al. ( , 1997, Laurie and Hill (1954), Malekian et al. (2010), Martin (2005), Matschie (1912Matschie ( , 1916aMatschie ( , 1916b Prideaux and Warburton (2008, Prideaux et al. (2007), Ramsay (1883), Rawlings and Donnellan (2003), Dollman (1933, 1936), Rothschild and Rothschild (1898), Rowe et al. (2011), Sanders and Lee (2007), Schneider et al. (1998), Schweizer et al. (2015, Taberlet et al. (1992), Tamura et al. (2011), Tate (1948, Thomas (1908), Todd et al. (2014), Toussaint et al. (2014), Le Souef (1936a, 1936b), Turnbull et al. (2003), Unmack et al. (2013), van Ufford and Cloos (2005), Westerman et al. (2006Westerman et al. ( , 2012, Wheeler et al. (2001), Windsor and Dagg (1971), Woodhead et al. (2016), Yang and Rannala (2006) and sources cited therein. In terms of the following descriptions it should be noted that the spelling of the names assigned to the species or subspecies should not be changed unless mandatory under the rules of the International Code of Zoological Nomenclature (Ride et al. 1999) or superseding documents. ...
An ongoing audit of vertebrate fauna in Australasia has revealed an unnamed species of Tree Kangaroo Dendrolagus Müller, 1840 from Tembagapura, Mimika, Irian Jaya, Indonesia. The purpose of this paper is to formally name the taxon. D. hoserae sp. nov. is not common and due to its specialized habitat requirements including relatively cold, high altitude habitat of limited land area, it is particularly vulnerable to extinction due to an ongoing increase in human population and activity in the area. Less immediate threats such as global warming, introduced competing species and pathogens may also cause the ultimate extinction of this little-known taxon. A subspecies of D. ursinus (Temminck, 1836) is also formally named for the first time.
Keywords: taxonomy; nomenclature; tree kangaroo; Irian Jaya; New Guinea; Indonesia; Dendrolagus;
dorianus; stellarum; mayri; ursinus; new species; hoserae; new subspecies; arfakensis.
Australasian Journal of Herpetology 40:50-55.
Published 10 July 2019.
... For Dendrolagus (8), the minimum bound (0.3 Mya) is based on Mt Etna fossils related to extant New Guinean tree kangaroos (Hocknull et al., 2007). A soft maximum bound at the Pliocene-Miocene boundary (5.333 ...
Kangaroos and wallabies of the Macropus complex include the largest extant marsupials and hopping mammals. They have traditionally been divided among the genus Macropus (with three subgenera: Macropus, Osphranter and Notamacropus) and the monotypic swamp wallaby, Wallabia bicolor. Recent retrotransposon and genome-scale phylogenetic analyses clarify the placement of Wallabia as sister to Notamacropus, with Osphranter and Macropus branching successively deeper. In view of the traditional Macropus concept being paraphyletic, we undertake to resolve the species-level phylogeny and genus-level taxonomy of the Macropus complex. For the first time, we include nuclear and mitochondrial DNA covering all extant species, and the first DNA sequences from the extinct Toolache wallaby (Notamacropus greyi), which we find groups with the black-gloved wallaby (Notamacropus irma). Morphological variation was examined using geometric morphometric methods on three-dimensional surface-scanned skulls. Wallabia skull shape fell close to Notamacropus (or Thylogale when controlling for allometry). We recommend the subgenera Macropus, Osphranter and Notamacropus be elevated to genera, alongside Wallabia, based on comparisons with other established macropodine genera for cranial disparity, ecology and molecular divergence. Our time tree estimates that all four ‘Macropus’ genera diverged close to the Miocene–Pliocene boundary (~6–5 Mya), then diversified coincident with Pliocene expansion of grasslands in Australia.
... Conversely, the most recent divergence of semiarid south-eastern and south-western population pairs had its upper limit at the Mid-Pleistocene, but including the Last Glacial Maximum, and may be related to changes in plants with palatable leaves and fleshy fruits that were present in the Nullarbor Region between 180,000 and 400,000 years ago but now are found in remnant stands on the fringes of the Nullarbor Plain (Prideaux et al. 2007). Similarly, Hocknull et al. (2007) noted extinction of mesic fauna in central eastern Australia within this timeframe. Phylogeographic analysis of southern hairy-nosed wombat identified six lineages across the southern arid region (Alpers et al. 2016). ...
Australia is a vast continent with a range of environments broadly differentiated into three major biomes. The best studied of these, the mesic biome, is confined to the eastern coast and the southeast and southwest corners and has pockets of ever-wet rainforest along the east coast. The monsoon tropics biome occurs in the northern part of the continent including Cape York Peninsula in the east, and the arid-zone biome covers the vast central and western parts of the continent, generally west of the Great Dividing Range. The arid zone is Australia’s largest biome, occupying approximately 70% of the entire continent (Fig. 1a) and broadly corresponding to the Eremaean and northern desert regions of the Australian Bioregionalisation Atlas (Ebach et al. 2015) (Fig. 1b). It covers a range of environments such as sandy deserts, gibber deserts and steppes, ranges and coastal plains and hosts a variety of vegetation types, shrub woodlands, acacia and mallee eucalypt shrublands, spinifex grasslands, tussock and hummock grasslands and chenopod shrublands. On average, the arid zone is only 300 m above sea level with low relief and a broad flat plain covering most of the central western area (Williams 1984; Pain et al. 2012; Pillans 2018).
... This was especially the case within larger refugia that showed increased richness of both winged and flightless species, especially in the Atherton Uplands. Larger refugia also sustained greater species richness and abundance of mammals (Williams 1997, Winter 1997, Hocknull et al. 2007, Williams et al. 2008a) Greater mammalian species richness and biomass increases dung beetle species richness. For example, more mammal species invariably increases resource (dung) heterogeneity (i.e. ...
This thesis investigates the drivers of, and predicts the impacts of future climate change on, endemic dung beetle biodiversity in the Australian Wet Tropics (AWT) rainforest. Specifically, the aims of the thesis were to: (1) derive accurate estimations of dung beetle “realised” distributions and species richness within the AWT, (2) identify and understand patterns and drivers of dung beetle biodiversity in the AWT bioregion and (3) along elevational gradients, and (4) predict the impacts of climate change on the endemic dung beetles of the AWT.
A new Old World trident bat (Rhinonycteridae) is described from an early Miocene cave deposit in the Riversleigh World Heritage Area, northwestern Queensland, Australia. Living rhinonycterids comprise a small family of insect-eating, nasal-emitting rhinolophoid bats from Africa, Madagascar, Seychelles, the Middle East, and northern Australia. The new fossil species is one of at least 12 rhinonycterid species known from the Oligo-Miocene cave deposits at Riversleigh. We refer the new species to the genus Xenorhinos (Hand, Journal of Vertebrate Paleontology, 18, 430-439, 1998a) because it shares a number of unusual cranial features with the type and only other species of the genus, X. halli, including a broad rostrum, very wide interorbital region, pronounced ventral flexion of the rostrum, very constricted sphenoidal bridge, and, within the nasal fossa, reduced bony division, and relatively well developed turbinals. Xenorhinos species lived in northern Australia during the global Miocene Climatic Optimum, in closed wet forests, unlike the drier habitats that trident bats largely inhabit today. Our phylogenetic analysis suggests that more than one dispersal event gave rise to the Australian rhinonycterid radiation, with two lineages having sister-group relationships with non-Australian taxa.
A new molecular phylogeny of a remarkable radiation of New Guinean and Australian rodents indicates multiple transitions between biomes and biogeographical regions within the group, and suggests that a key role was played by the geological history of New Guinea.
The extant pig-nosed turtle (Carettochelys insculpta), persisting in far northern Australia and southern New Guinea, is the last surviving member of Carettochelyidae and the only non-Gondwanan freshwater turtle lineage in Australia. Despite having a global fossil record dating to the Cretaceous, the absence of carettochelyid fossils from Australia has implied a relatively recent colonization of this landmass. Here we report an upper Miocene to lower Pliocene carettochelyid fossil from Beaumaris, Victoria, in south-eastern Australia. This record is the most southerly occurrence of the clade Carettochelyidae. The presence of carettochelyids in southern Australia, and a discontinuous record of trionychids (soft-shell turtles) in the Cenozoic of Queensland, suggests at least two colonizations of Australia by Trionychia, pre-dating the extant pig-nosed turtle. This cryptic southern history of tropical soft-shell and pig-nosed turtles ended before the recent aridification of Australia, leaving the Gondwanan side-necked turtles as the dominant turtle group in Australian freshwater ecosystems. Therefore, this singular fossil reveals a previously unknown shift in the diversity and evolutionary history of freshwater turtles in Australia.
Why do organisms look the way they do? Why do they live where they do? Why are some groups more diverse than others? These basic questions are often addressed at different scales using a particular set of methods. For example, the first question could be addressed by either looking at phenotypes across a phylogeny in a comparative framework or by looking at fine scale variation across the landscape within a species. However, it has been challenging to build a conceptual and methodological bridge linking ecological processes and population dynamics with evolutionary and biogeographic patterns above the species level. In this thesis, I present research spanning a broad range in the continuum between micro- and macroevolution. Appropriately, my study system is monitor lizards (Squamata: Varanidae), the terrestrial vertebrate genus showing the largest disparity in body size. These charismatic reptiles display notable variation in species richness, morphology, and ecology across the three continents and numerous oceanic islands they call home. I gathered large molecular, morphological, and environmental datasets and analysed them using process-based methods linking ecological and population-level processes with speciation and macroevolutionary patterns. I used this integrative approach to identify the drivers of genetic, phenotypic, and lineage diversification in Varanidae at different evolutionary scales. In Chapter I, I show that the diversification dynamics of three endemic varanid radiations in Indo-Australasia have been dictated by a combination of geography and interspecific interactions. In Chapter II, I demonstrate that ontogenetic lability is behind morphological diversification in varanids and their kin, and that ontogenetic ecological shifts in ecology explain some of the ontogenetic variation in the group. In Chapter III, I used a comprehensive approach to uncover signs of ancient hybridization between the iconic Komodo dragon and a group of Australian varanids, corroborating the Australian origin of the former. In Chapter IV, I evaluate species limits in spiny-tailed monitors and present genomic and phenotypic evidence for local adaptation despite extensive gene flow. Together, these chapters show how the integration of multiple sources of evidence can offer insight into the long-term evolutionary consequences of developmental, ecological, and population-level processes.
There is a distinct lack of information regarding interactions between thylacine ( Thylacinus cynocephalus ) and Aboriginal Australians. Their depiction in Australian rock art is not unusual, yet only one example of an artefact made from thylacine remains has been recovered from the archaeological record. This absence of thylacine‐based Indigenous material culture is conspicuous, especially since the raw materials such a large mammal provides would be useful and thus their depiction in art but absence from “things” appears significant. To investigate whether substantial opportunity existed for the exploitation of thylacines for the purpose of material culture production, and thus that sampling or cultural factors must instead be at play for their absence from the record, the location of known palaeontological, archaeological and rock art sites related to thylacines were mapped in time and space. Dated contexts are compared to create an overall picture of the overlap between thylacine habitat and human territories. We found that there was a significant period where interaction between this enigmatic animal and First Australians occurred, and, therefore, a lack of contact is not the reason for the near total absence of thylacine bones, teeth and other materials being missing from Indigenous material culture
Spotlight surveys are widely used to monitor arid-zone-dwelling species such as the greater bilby (Macrotis lagotis). These surveys require a sufficient sample size to adequately model detection probability. Adequate sample sizes can be difficult to obtain for low-density populations and for species that avoid light and or have poor eyeshine like the bilby. Abundance estimates based on burrow counts can be problematic because of the variable relationship between the number of burrows used and bilby abundance. In 2013, feral predators devastated a Queensland bilby population and a method was required that could locate and monitor the remaining bilbies. We report on a study that compared density estimates derived from spotlighting and thermal cameras. Bilbies were surveyed annually over three years, using spotlights and thermal cameras on different nights but using the same transects to compare the methods. On average, thermal cameras detected twice the number of bilbies per kilometre surveyed than spotlighting. Despite this difference in the number of bilbies detected, density estimates (bilbies km−2) were similar (thermal camera versus spotlight: 0.6 versus 0.2 (2014), 3.4 versus 3.4 (2015) and 4.8 versus 3.3 (2016)). Nevertheless, the larger sample size obtained using thermal cameras gave greater confidence in modelling detection probability.
Population divergence and gene flow are key processes in evolution and ecology. Model-based analysis of genome-wide datasets allows discrimination between alternative scenarios for these processes even in non-model taxa. We used two complementary approaches (one based on the blockwise site frequency spectrum (bSFS), the second on the Pairwise Sequentially Markovian Coalescent (PSMC)) to infer the divergence history of a fig wasp, Pleistodontes nigriventris. Pleistodontes nigriventris and its fig tree mutualist Ficus watkinsiana are restricted to rain forest patches along the eastern coast of Australia, and are separated into northern and southern populations by two dry forest corridors (the Burdekin and St. Lawrence Gaps). We generated whole genome sequence data for two haploid males per population and used the bSFS approach to infer the timing of divergence between northern and southern populations of P. nigriventris, and to discriminate between alternative isolation with migration (IM) and instantaneous admixture (ADM) models of post divergence gene flow. Pleistodontes nigriventris has low genetic diversity (π = 0.0008), to our knowledge one of the lowest estimates reported for a sexually reproducing arthropod. We find strongest support for an ADM model in which the two populations diverged ca. 196kya in the late Pleistocene, with almost 25% of northern lineages introduced from the south during an admixture event ca. 57kya. This divergence history is highly concordant with individual population demographies inferred from each pair of haploid males using PSMC. Our analysis illustrates the inferences possible with genome-level data for small population samples of tiny, non-model organisms and adds to a growing body of knowledge on the population structure of Australian rain forest taxa.
The Pig-footed Bandicoot, Chaeropus ecaudatus, an extinct arid-adapted bandicoot, was named in 1838 based on a specimen without a tail from the Murray River in New South Wales. Two additional species were later named, C. castanotis and C. occidentalis, which have since been synonymised with C. ecaudatus. Taxonomic research on the genus is rather difficult because of the limited material available for study. Aside from the types of C. castanotis and C. occidentalis housed at the Natural History Museum in London, and the type of C. ecaudatus at the Australian Museum in Sydney, there are fewer than 30 other modern specimens in other collections scattered around the world. Examining skeletal and dental characters for several specimens, and using a combination of traditional morphology, morphometrics, palaeontology and molecular phylogenetics, we have identified two distinct species, C. ecaudatus and C. yirratji sp. nov., with C. ecaudatus having two distinct subspecies, C. e. ecaudatus and C. e. occidentalis. We use palaeontological data to reconstruct the pre-European distribution of the two species, and review the ecological information known about these extinct taxa.
Combined "total evidence" analysis of molecular and morphological data offers the opportunity to objectively merge fossils into the tree of life, and challenges the primacy of solely DNA based phylogenetic and dating inference, even among modern taxa. To investigate the relative utility of DNA, morphology, and total evidence for evolutionary inference, we sequenced the first near-complete mitochondrial genomes from extinct Australian megafauna: a 40-50 thousand year old giant short-faced kangaroo (Simosthenurus occidentalis) and giant wallaby (Protemnodon anak). We analysed the ancient DNA and fossil data alongside comparable data from extant species to infer phylogeny, divergence times, and ancestral body mass among macropods (kangaroos and wallabies). Our results confirm a close relationship between Protemnodon and the iconic kangaroo genus complex "Macropus", and unite the giant Simothenurus with the hare-sized Lagostrophus fasciatus (banded hare-wallaby), suggesting that the latter is the closest living link to the once diverse sthenurine kangaroo radiation. We find that large body size evolved multiple times among kangaroos, coincident with expansion of open woodland habitats beginning in the Late Miocene. In addition, our results suggest that morphological data mislead macropod phylogeny reconstruction and in turn can distort total evidence estimation of divergence dates. However, a novel result with potentially broad application is that the accuracy and precision of reconstructing ancestral body mass was improved by tracing body mass on morphological branch lengths. This is likely due to positive allometric correlation between morphological and body size variation - a relationship that may be masked or even misleadingly inverted with the temporal or molecular branch lengths that typically underpin ancestral body size reconstruction. Our study supports complementary roles for DNA and morphology in evolutionary inference, and opens a new window into the evolution of Australia's unique marsupial fauna.
Melomys cervinipes (Gould, 1852) is a murid rodent commonly called the fawn-footed mosaic-tailed rat. A small, russet brown rodent with light fawn-colored feet, it is 1 of 21 currently recognized species in the genus Melomys. The species is endemic to Australia, occurring in the rainforests and forests along the eastern coast. M. cervinipes is listed as "Least Concern" by the International Union for the Conservation of Nature and Natural Resources.
A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheettype data entry with univariate and multivariate statistics, curve fitting, time-series analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.
Archer. M. et a\..1999. The evolutionary history and diversity of Australian mammals. Australian Mammalogy 2l: 1-45. Palaeodiversity and relationships of all groups of Australian mammals are reviewed. The fossil record spanning this time is of variable quality. 'Dark Ages'about which nothing is known in terms of Australian mammal evolution include the late Triassic to late Jurassic, late Cretaceous to late Paleocene and middle Eocene to middle Oligocene. Very little is known about the early Cretaceous and late Miocene. The late Oligocene to middle Miocene record documents the highest levels of biodiversity known for the continent, comparabie to that which characterises the lowland rainforests of Borneo and Brazil. Order Monotremata spans at least the last 110 million years and includes four families. The enigmatic Ausktribosphenos from I 15 million-year-old sediments in Victoria may ..piesent an archaic monotreme, specialised peramurid or previously undocumented order of mammals but is unlikely to represent a placental as suggested in the initial description. Order Microbiotheria is represented in the early Eocene (-55 mya) by two genera similar in morphology to early Eocene taxa from Argentina. Order Peramelemorphia spans the early Eocine to Holocene and includes at least five families. Order Dasyuromorphia spans at least the late Oligocene to Holocene and includes at least three families. Other dasyuromorphian-like marsupials are indeterminate in terms of family-level affinities. Order Notoryctemorphia spans the early Miocene to Holocene rvith one family. Order Yalkaparidontia spans the late Oligocene to middle Miocene with one genus. Order Diprotodontia spans the late Oligocene to Holocene, represented throughout by three *ujot groups: Phalangerida (eight families), Vombatomorphia (seven families) and Macropodoidea (at least three families). A possible placental condylarth (Tingamarua) has been iecorded from the early Eocene. An archaeonycteridid bat (Australonycteris) is known from the early Eocene. Among bats, the late Oligocene to middle Miocene is dominated by rhinolophoids, many of which have European, Asian and African affinities. Mystacinids, megadermatids, hipposiderids and molossids are rvell-represented in the Oligocene to Miocene deposits. Vespertilionids are uncommon in the Oligocene to Miocene but become more diverse in the Pliocene to Holocene. Emballonurids and rhinolophids appear for the first time in the Plio-Pleistocene. Pteropodids are unknown prior to the Holocene. Murids span the early Pliocene to Holocene. In the oldest assemblage at Riversleigh. one undescribed lineage resembles archaic forms otherwise only known from the fossil records of Africa and Eurasia. tschool of Biotogicat Science, (tniversity ofNew South llales, Sydney 2052; 2Centre for Research into the Evolution of Australia's Terrestrial Ecosystems, Australian Museum, 6-8 College St, Sydney, NSII 2000; tschool of nuatural Resource sciences, .oueensland
The faunas found in the mountains of central Irian Jaya have experienced dramatic changes through the late Quaternary. Remains of two previously unknown species of large marsupial, Maokopia ronaldi and Protemnodon hopei, have been recovered from unrelated cave and fluvial deposits which today occur in dense upper montane forest. Direct dating of the finds has not as yet been possible, but stratigraphic, sedimentologic, and palynologic evidence indicates that these species lived near a climatic treeline in subalpine grassland in the late Pleistocene. At higher altitudes a rockshelter provided the second known mid-Holocene record of Thylogale christenseni and Thylogale sp. cf. brunii, apparently extinct grassland wallabies. The two largest remaining subalpine mammal species are being locally exterminated by hunting, leaving only a large murid, Mallomys gunung, which weighs less than 2.0 kg. The area thus records the disappearance of a grassland-adapted fauna. The possum Pseudocheirops cupreus dominates in modem hunting returns, although this species is totally absent from the local fossil records. It may thus be in the process of invading a vacated and disturbed niche from the upper montane forest.
Stony deserts are durable indicators of aridity but until now have not been directly dated. Using 21Ne and 10Be produced in surface rocks by cosmic rays, we show that Australian stony deserts formed 2 4 Ma, at the time when global cooling initiated the Quaternary ice ages and intensified aridity-induced major landscape changes in central Australia. This is the first direct determination of stony desert ages, using a new method for determining cosmogenic 21Ne in the presence of various neon components from other sources.
The global blitzkrieg hypothesis explains differential rates of megafaunal extinction between the world's landmasses in the late Quaternary based on a proposed leap in predation efficiency enjoyed by colonising societies. It is characterised by appealing simplicity. Selective over hunting, facilitated by naiveté to human predation, produced rapid mass extinctions of large animals wherever subsistence societies colonised new landmasses. Taken at face value the circumstantial case for blitzkrieg is compelling and despite a paucity of direct evidence it has gained considerable support. Our review of the model suggests that it overlooks much contradictory data and rests on simplistic interpretations of complex biogeographicat and anthropological phenomena. These interpretations and assumptions do not account for major differences between the biotas, ecologies and human cultures of the landmasses involved. The assertion that responses of remote island species to human predation provide realistic models for those of continental taxa is poorly founded, exaggerating the likely predation efficiency of humans colonising continents. An absence of terrestrial predators over evolutionarily significant periods, together with restricted ranges and small populations, renders island faunas uniquely vulnerable to invaders. The argument, that climate cannot explain these phenomena because previous Glacial Maxima did not cause comparable extinctions, presupposes that their local effects were at least as severe as those of the Last Glacial Maximum. This has yet to be demonstrated and at most it would indirectly support a role for anthropogenic influence, not overkill per se. Overlooked or underplayed are the influences of translocated and other invading species. Similarly, differences in the origins, technologies and traditions of colonising human societies are rarely considered. These factors strongly impact on the predation efficiency, density and range of human populations, critically affecting the outcomes of predator-prey modeling. When a fuller constellation of influences and constraints is considered it is reasonable to posit that rapid mass extinction through selective human predation may largely describe megafaunal extinctions on remote islands, but the argument is not convincing for continents. This is especially so regarding Australia. Because even the largest Australian species were prey to endemic carnivores, their responses to human predation would not have been comparable to those of oceanic island species. No kill-sites or specialized big-game hunting/butchering tools are known and, on the basis of ethnographic and archaeological data, it is probable that predation efficiency, population density and range of the first Australians were insufficient to effect rapid mass extinction. Chronologies of human arrival and the disappearance of megafauna remain poor, but the most recent estimates for human-megafaunal coexistence in Australia range from 10,000 to 43,000 years. Although human predation may have been a contributing factor in megafaunal extinctions, rapid overkill is unlikely to describe the actual mechanism in most instances. The role of human predation and its significance relative to competing factors, human and otherwise, varied considerably between landmasses, as did the speeds with which extinctions occurred. Blitzkrieg and other mono-factorial models are heuristically valuable devices, but a growing body of evidence suggests that extinction can rarely, if ever, be attributed to a single cause.
The Murray-Darling river system in southeastern Australia formerly flowed into a large lake, Lake Bungunnia, before reaching the sea. Fine-grained clastics of this system, the Blanchetown Clay Formation, extend over an area of about 68,000 km2 underlying the Mallee region with its surface array of dunes and salt lakes. Palaeomagnetic analyses are used to date the major hydrologic transition from the expansive freshwater system to the saline deflation playas and dunes that characterize this landscape today.
Mass spectrometric U-series dating of speleothems from Tangshan Cave, combined with ecological and paleoclimatic evidence, indicates that Nanjing Man, a typical Homo erectus morphologically correlated with Peking Man at Zhoukoudian, should be at least 580 k.y. old, or more likely lived during the glacial oxygen isotope stage 16 (similar to 620 ka). Such an age estimate, which is similar to 270 ka older than previous electron spin resonance and alpha counting U-series dates, has significant implications for the evolution of Asian H. erectus. Dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages, that of the enamel sample being only less than one-fourth of the minimum age of Nanjing Man. This suggests that U uptake history is far more complex than existing models can handle. As a result, great care must be taken in the interpretation of electron spin resonance and U-series dates of fossil teeth.
It is now widely accepted that global climate change is affecting many ecosystems around the globe and that its impact is increasing rapidly. Many studies predict that impacts will consist largely of shifts in latitudinal and altitudinal distributions. However, we demonstrate that the impacts of global climate change in the tropical rainforests of northeastern Australia have the potential to result in many extinctions. We develop bioclimatic models of spatial distribution for the regionally endemic rainforest vertebrates and use these models to predict the effects of climate warming on species distributions. Increasing temperature is predicted to result in significant reduction or complete loss of the core environment of all regionally endemic vertebrates. Extinction rates caused by the complete loss of core environments are likely to be severe, nonlinear, with losses increasing rapidly beyond an increase of 2 degrees C, and compounded by other climate-related impacts. Mountain ecosystems around the world, such as the Australian Wet Tropics bioregion, are very diverse, often with high levels of restricted endemism, and are therefore important areas of biodiversity. The results presented here suggest that these systems are severely threatened by climate change.
Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.
The Antarctic Vostok ice core provided compelling evidence of the nature of climate, and of climate feedbacks, over the past 420,000 years. Marine records suggest that the amplitude of climate variability was smaller before that time, but such records are often poorly resolved. Moreover, it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records. Here we report the recovery of a deep ice core from Dome C, Antarctica, that provides a climate record for the past 740,000 years. For the four most recent glacial cycles, the data agree well with the record from Vostok. The earlier period, between 740,000 and 430,000 years ago, was characterized by less pronounced warmth in interglacial periods in Antarctica, but a higher proportion of each cycle was spent in the warm mode. The transition from glacial to interglacial conditions about 430,000 years ago (Termination V) resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases, but there are significant differences in the patterns of change. The interglacial stage following Termination V was exceptionally long--28,000 years compared to, for example, the 12,000 years recorded so far in the present interglacial period. Given the similarities between this earlier warm period and today, our results may imply that without human intervention, a climate similar to the present one would extend well into the future.
About 850,000 years ago, the period of the glacial cycles changed from 41,000 to 100,000 years. This mid-Pleistocene climate transition has been attributed to global cooling, possibly caused by a decrease in atmospheric carbon dioxide concentrations. However, evidence for such cooling is currently restricted to the cool upwelling regions in the eastern equatorial oceans, although the tropical warm pools on the western side of the ocean basins are particularly sensitive to changes in radiative forcing. Here we present high-resolution records of sea surface temperatures spanning the past 1.75 million years, obtained from oxygen isotopes and Mg/Ca ratios in planktonic foraminifera from the western Pacific warm pool. In contrast with the eastern equatorial regions, sea surface temperatures in the western Pacific warm pool are relatively stable throughout the Pleistocene epoch, implying little long-term change in the tropical net radiation budget. Our results challenge the hypothesis of a gradual decrease in atmospheric carbon dioxide concentrations as a dominant trigger of the longer glacial cycles since 850,000 years ago. Instead, we infer that the temperature contrast across the equatorial Pacific Ocean increased, which might have had a significant influence on the mid-Pleistocene climate transition.
New late Cainozoic faunal assemblages are preliminarily identified and described from central eastern Queensland. Biocorrelation of the sites has determined that the oldest faunal assemblages are Early Pliocene in age, with younger faunas from the Plio-Pleistocene, late Pleistocene and Holocene. Pliocene faunal assemblages are characterised by rainforest-specialist frog, squamate and mammalian taxa. These include new Pliocene records for frogs; Kyarranus, Lechriodus, Nyctimystes and microhylids, squamates; Cyclodomorphus gerrardii, a new species of Tiliqua and typholopids, and mammals; Bohra sp., Pseudochirulus spp., new petaurids and dasyurids, Dactylopsila, petauroid incertae sedis, Acrobates, Cercartetus, Uromys/Melomys, Mesembriomys and Pogonomys. Ecological signals derived from the faunal assemblages correlate well with dated palynological records from central eastern and northern Queensland (ODP815, Aquarius Well and Lynch's Crater). Combined Early Pliocene palynological and faunal records strongly indicates a nonseasonal, mesothermal, angiosperm-dominant rainforest with emergent gymnosperms at Mount Etna. A Plio-Pleistocene seasonal, open ecology indicated by the palynological record is corroborated by fauna from similar-aged sites, although several rainforest taxa persist. Increasing aridity during the late Pleistocene is suggested by a distinctly arid-adapted faunal assemblage in late Pleistocene sites, including eastern-most records of Tympanocryptis, Macrotis lagotis, Chaeropus ecaudatus, Perameles bougainville, Sminthopsis macroura and Notomys. Faunal succession from the Early Pliocene to Holocene is characterised by the extinction of most rainforest groups by the late Pleistocene, being replaced by more xeric-adapted forms. Several of the Early Pliocene taxa show resilience to extinction by remaining, albeit rare, in the late Pleistocene fauna, probably in local refugia. These include Dendrolagus sp., a new petauroid, Thylogale, Macroderma gigas, Sarcophilus laniarius and Thylacinus. Presence of rainforest murids in the Early Pliocene of Australia significantly predates previous estimates for their dispersal onto mainland Australia.
Two new boreholes provide the first direct evidence of the age of the Australian Great Barrier Reef. An inner shelf sequence (total depth, 86 m; basal age = 210 ± 40 ka) comprises a dominantly siliciclastic unit (thickness ∼52-86 m), overlain by four carbonate units (total thickness 0-34 m). A shelf-edge and slope sequence (total depth 210 m) reveals three major sections: (1) a lower section of resedimented flows deposited on a lower slope, (2) a mid-section including intervals of corals, rhodoliths, and calcarenites with low-angle graded laminae, and (3) an upper section of four shelf-margin coral-reef units separated by karst surfaces bearing paleosols. Sr isotope and magnetostratigraphic data indicate that the central Great Barrier Reef is relatively young (post Brühnes-Matuyama boundary time), and our best estimate for the onset of reef growth on the outer barrier system is ca. 600 ± 280 ka. This date suggests that reef initiation may have been related to the onset of full eccentricity-dominated glacio-eustatic sea-level oscillation as inferred from large-amplitude "saw-tooth" 100 k.y. δ18O cycles (after marine isotope stage 17), rather than to some regional environmental parameter. A major question raised by our study is whether reef margins globally display a similar growth history. The possibility of a global reef initiation event has important implications for basin to shelf partitioning of CaCO3, atmospheric carbon dioxide levels, and global temperature change during Quaternary time.
While families have historically provided the basis of business organization in the United States, in the late nineteenth century the development of corporations and managerial capitalism weakened their role in business, especially in management (Bell 1962; Chandler 1977; Farber 1972; Hall 1977,1988; Kanter 1978; Mills 1956; Shammas et al. 1987). Chandler (1977) has postulated a historical decline in family management, control, and decision making in firms with the growth of industrial capitalism; others have asserted a continued presence of the family in business ownership (Davis and Stern 1980; Lansberg et al. 1988).
In coastal sections at Hallett Cove and Sellicks Beach, south of Adelaide, and
at Redbanks section on Kangaroo Island, the Brunhes/Matuyama polarity
transition (780 ka) is identified in the strongly oxide-mottled Ochre Cove
Formation. At all 3 sections, the Ochre Cove Formation is overlain by a
calcareous grey-green aeolian clay, called Ngaltinga Clay, which in turn is
overlain by calcareous sediments of the Taringa and Christies Beach
Formations. The marked change from an oxide-dominated weathering regime to a
carbonate-dominated weathering regime, estimated to have occurred at about
500–600 ka, is interpreted as a major arid shift in regional climates.
Similar arid shifts are known from Lake Bungunnia in the Murray Basin and Lake
Lefroy in southern Western Australia, where changes from lacustrine clays to
evaporites and dune sediments are estimated to have occurred between 400 and
700 ka, and about 500 ka, respectively. An increase in aeolian dust accession
in south-eastern Australia, consistent with increased aridity in the interior
source area, occurred after 780 ka, and was probably coeval with increased
dust input to Tasman Sea sediments since 350 ka.
Between 600 and 900 ka, oxygen isotope fluctuations in deep-sea cores showed a
pronounced change in frequency, from a 40 ka (obliquity dominated) to a 100 ka
(eccentricity dominated) pattern. At the same time, glacial-interglacial
amplitudes increased, with a marked enrichment of glacial
d18O values consistent with larger continental based
ice-sheets. Colder global temperatures, and lower sea levels during glacials,
may have played a part in the mid Pleistocene arid shift recorded in southern
Australia. Associated variations in the strength of the warm Leeuwin Current
may also have affected regional rainfall patterns in southern Australia.
It is generally recognised that the distribution of vertebrates in rainforest
and wet sclerophyll forest of the Wet Tropics region of north-eastern
Australia is profoundly influenced by the formation of two rainforest refugia
at the height of Pleistocene glacial periods. Anomalies in the distribution of
non-volant mammals indicate that other events may be equally important. In
this paper, past geographical occurrence of non-volant mammals is examined by
equating the mammals’ known temperature tolerance with palaeoclimatic
temperature zones. It is hypothesised that dispersal and vicariant phases
taking place since the most recent glacial period have had a profound
influence on current patterns of distribution. A major dispersal phase of
cool-adapted species occurred after the glacial period, and continuous
populations were subsequently fragmented into upland isolates by expansion of
warm rainforest during the late post-glacial period. These upland isolates
remain substantially unchanged to the present day. Species shared either with
New Guinea or south-eastern Australia arrived in the region during the most
recent post-glacial period. Clarification of periods of vicariance and
dispersal provides a conceptual framework for testing relative divergences of
populations within and between regions.
Sediments from Lake Amadeus, a groundwater discharge playa in central Australia, comprise a surface playa sequence (the Winmatti Beds), varying between 0.6 and 3 m in thickness, overlying a long sequence of fairly uniform fluvial-lacustrine clays (the Uluru Clay). The latter extends down to at least 15 m (the maximum depth cored during this study), and possibly down to 65 m below the present playa surface. In the cores studied the Brunhes-Matuyama boundary (0.73 Ma) was identifiable in all the upper sediments, typically at a depth of between 1 and 2 m, but below this there are two plausible chronological interpretations of the palaeomagnetic data. Deposition rates are very low, typically no more than 1.5 cm/ka in the Uluru Clay Beds, and down to 0.2 cm/ka in the Winmatti Beds. These rates suggest that the fluvial-lacustrine phase lasted for at least 5 Ma.
Climatic conditions in the western Timor Sea and the adjacent northwestern part of Australia are reconstructed for the last 460 ka, based on geochemical and palynological proxy records of paleoproductivity and land vegetation (precipitation) from IMAGES Core MD01-2378. Reduced precipitation and elevated productivity characterize glacial stages, whereas enhanced precipitation and reduced productivity are typical of interglacial stages. A long-term reduction in precipitation over the last 320 ka occurred in two steps at approximately 300 ka and 180 ka BP that are clearly recognizable in the pollen record. Variations in paleoproductivity and paleoclimate in the Timor Sea and adjacent landmasses appear to be driven by similar mechanisms that are related to the precession-controlled Australian monsoon system.
Magela Creek, a major tributary of the East Alligator River in northern Australia, has left a detailed sedimentary record of a fluvial landscape dominated by climatic and eustatic changes associated with Quaternary glacial-interglacial cycles. Uranium-series dates from young pisoliths in floodplain deposits indicate that ferruginisation is probably ongoing under present conditions while ferricretes in degraded terraces that flank the lower valley reveal a fluvial history extending back to early Pleistocene or Tertiary time. Inset within this older alluvium is a valley fill which, from thermoluminescence dates, was initiated about 300 kyr ago. With each glacial climate change and associated fall in sea level, distinct palaeochannels have been eroded into these floodplains, infilling later with alluvium when climate and base-level conditions were conducive to fluvial deposition. Radiocarbon dates show that the most recent palaeochannel beneath the modern Magela Creek last started to fill by downstream progradation and vertical accretion of bedload sand about 8 kyr. The palaeochannel filled at an accelerating rate, probably as a result of declining stream competence associated with drier conditions in the late Holocene augmented by the backwater effects of sea-level rise. Continued aggradation blocked the mouths of tributary valleys along Magela Creek, forming alluvial-dammed tributary lakes and deferred-junction tributary streams. From about 300 kyr, cyclic episodes of channel incision and sediment evacuation in this tropical-monsoon river valley have become less effective, possibly because increasing aridity in the late Quaternary has reduced the erosional effectiveness of Australia's northern rivers. Reduced flow regime and rising sea level in the late Holocene has resulted in the latest phase of alluvial accretion.
Recent chronostratigraphic evidence suggests that the central Australian Great Barrier Reef formed within the past 780 k.y. Periplatform sediments of the same age recovered from the western Coral Sea record a progressive decrease in the delta18O of planktonic foraminifera to the present. Several investigators have proposed that this trend represents an appreciable late Pleistocene warming (˜4 °C) of ocean surface temperatures, which they posit catalyzed the growth of the Great Barrier Reef. Contrary to this hypothesis, we demonstrate using alkenone paleothermometry (U37k') on sediments from Ocean Drilling Program (ODP) Site 820 that sea-surface temperatures (SSTs) in the western Coral Sea changed by ˜1.5 °C or less during the past ˜800 k.y. If the central Great Barrier Reef rose in the late Quaternary, it was therefore not due to a warming of SSTs. We explore whether a major moisture balance change and/or diagenetic alteration of calcareous microfossils can explain the higher delta18O values observed at depth in the planktonic delta18O record at ODP Site 820. Our results suggest that diagenesis provides a large isotopic overprint.
The Nelson Bay Local Fauna, recovered from a paleosol horizon exposed in the sea cliffs at Nelson Bay, Portland, Victoria, Australia, comprises over 30 different mammalian species making it one of the most diverse early Pleistocene faunas in Australia. Its age is well constrained to 1.77–0.78 Ma by radiometric, biostratigraphic and paleomagnetic dating methods. The composition of the fauna, which includes predominantly browsing-grade taxa and a number of arboreal species, suggests the paleoenvironment was a mosaic of open forest and woodland. This habitat acted as a refuge for forest-adapted taxa previously known only from the early Pliocene, such as the ektopodontid, Darcius duggani, the giant ring-tailed possum, Pseudokoala, a small palorchestid, Palorchestes pickeringi, and a new species of Protemnodon. The Nelson Bay Local Fauna was compared at the generic level with six other faunas ranging in age from early Pliocene to Recent using Simpson's coefficient of faunal resemblance. This analysis shows the Nelson Bay Local Fauna, with its combination of extant, typical Pleistocene megafauna, and ‘relict’ Pliocene species, to be unusual in the region. The combination of taxa in the Nelson Bay Local Fauna may be characteristic of early Pleistocene terrestrial mammal assemblages of southeastern Australia, and could be used cautiously to date other faunas, e.g., Childers Cove Local Fauna.
Oxygen-isotope ratio measurements are presented for the planktonic species Globigerinoides ruber collected from shallow- water, upper-slope sediments from Holes 820A and 820B in 280 m of water, on the seaward edge of the Great Barrier Reef. Correlation of the Site 820 isotope curve with deep-sea reference curves of the Pacific Ocean (Core V28-238, Hole 677A, Hole 607A) permits the definition of isotope stages 1 to 19 in the top 145 m of Holes 820A and 820B. However, paleontological data indicate that stages 4 and 7 might be missing and that two hiatuses occur at a depth of 8.05 to 12.1 and 34.55 to 35.8 mbsf. Using deep-sea Hole 677A as a reference for ice-volume variations, we determine the difference in isotopic signature between it and Site 820. We propose that this difference is a regional signal representing a progressive 4°C increase in surface-water temperature at Site 820. The proposed temperature change was initiated at about 400 k.y. and corresponds to a change from high-to-low frequency variations in Pleistocene isotope signals. We postulate that these changes may have catalyzed the growth of the Great Barrier Reef. The shift also coincides with changes in seismic character and some physical and chemical sediment characteristics.
Two new boreholes provide the first direct evidence of the age
of the Australian Great Barrier Reef. An inner shelf sequence (total
depth, 86 m; basal age 5 210 6 40 ka) comprises a dominantly
siliciclastic unit (thickness ;52–86 m), overlain by four carbonate
units (total thickness 0–34 m). A shelf-edge and slope sequence
(total depth 210 m) reveals three major sections: (1) a lower section
of resedimented flows deposited on a lower slope, (2) a mid-section
including intervals of corals, rhodoliths, and calcarenites with lowangle
graded laminae, and (3) an upper section of four shelfmargin
coral-reef units separated by karst surfaces bearing paleosols.
Sr isotope and magnetostratigraphic data indicate that the
central Great Barrier Reef is relatively young (post Bru¨hnes-Matuyama
boundary time), and our best estimate for the onset of reef
growth on the outer barrier system is ca. 600 6 280 ka. This date
suggests that reef initiation may have been related to the onset of
full eccentricity-dominated glacio-eustatic sea-level oscillation as
inferred from large-amplitude ‘‘saw-tooth’’ 100 k.y. d18O cycles
(after marine isotope stage 17), rather than to some regional environmental
parameter. A major question raised by our study is
whether reef margins globally display a similar growth history.
The possibility of a global reef initiation event has important implications
for basin to shelf partitioning of CaCO3, atmospheric
carbon dioxide levels, and global temperature change during Quaternary
time.
A Quaternary sedimentary sequence (ca. 600 ka) from a perched lake (Old Lake Coomboo Depression) on the World Heritage-listed coastal sandmass of Fraser Island has been analysed for dry bulk density, carbonised particles, pollen and chemistry. A chronology has been constructed for the organic sediments using a combination of radiocarbon and uranium/thorium disequilibrium analysis. The lake basin is small (ca. 9 ha) with a restricted groundwater catchment, delimited by an aquitard, and minimal surface runoff. It therefore acts as a sensitive raingauge with the perched groundwater-table, and hence the sediment facies deposited within the lake, reacting sensitively to any changes in the water budget. The sequence passes through a series of glacial cycles, demonstrating hydrologic and vegetation change. The record indicates a long-term, three-stage fall in the water-table from lake-full ca. 600 ka to an ephemeral lake in the Holocene, paralleled by a shift in the vegetation composition from predominantly rainforest to sclerophyllous components. The evidence for fire is minimal at the beginning of the record, increases from >350 ka through the sequence culminating at or before the LGM, is low during the LGM and is relatively high during the Holocene. Succession, fire and climatic change, along with the accumulative effect of a series of 100 ka cycles, are believed to have driven the hydrologic and vegetation change and a human factor is not required to explain the record. Within the overall long-term increase in aridity recorded through about six glacial cycles, there appears to be a variation in the ‘dryness’ signal of glacial maxima, suggesting some form of ‘supercycle’ phenomenon.
The limestone caves of the Naracoorte region in South Australia contain extensive deposits of megafauna-rich sediments and intercalated cave formation (speleothems). High-precision thermal ionisation mass spectrometry (TIMS) U/Th dating of flowstones directly associated with several large deposits reveals a distinct cyclicity in the timing of sediment and flowstone depositional events in the Naracoorte caves. This pattern parallels a cyclical alternation of ‘Wet Phases’, and intervening periods with a water deficit over the last 500 ka (Ayliffe et al., 1998. Geology 26, 147). Dates from flowstone interlayers in the fossil deposits coincide with the massive speleothem growth events which characterise Wet Phases. Hiatuses in flowstone deposition correlatable through several cave systems imply that water deficits were initiated by regional aridity during full glacial and then extended into the succeeding warmer, wetter interglacials. Clastic deposits in caverns with restricted entrance shafts correlate with hiatuses, suggesting many of these deposits contain fauna representative of full glacial and interglacial climates. Caverns with small openings have often been sealed from the surface and dating has constrained the length of accumulation episodes in several fossil deposits, one to less than 20 ka. The hydrological regimes and environmental conditions inferred from the timing of speleothem deposition have been used to develop a model for cyclic sediment and bone accumulation in the caverns at Naracoorte over the last 400 ka. The giant Victoria Fossil Chamber deposit accumulated prior to 200 ka and because its entrance is large it may contain faunas representative of all climatic phases. There has been no apparent change in faunal diversity at Naracoorte over at least three glacial–interglacial cycles of the Middle Pleistocene.
Lake Lefroy and Lake Cowan occur in the relic Tertiary palaeodrainage that used to drain to the east in central western Australia. Lacustrine conditions prevailed during the late Neogene and the early part of the Quaternary. Strong aridity sets in during mid-Quaternary, resulting in extensive gypsum precipitation and eolian deposition in and around the playa lakes. Lakes Lefroy and Cowan are now hypersaline and deflating, with a salt crust developed on the lake floor and lunette dunes constructed along the eastern margins. Optical dating (green light-stimulated luminescence (GLSL) dating) of the lunette dunes along the eastern and southeastern margins of the playas and electron spin resonance (ESR) dating of relic gypsum dunes on the lake floor show that intensified eolian activity occurred during the last glacial period, with a major lunette construction phase occurring during the Last Glacial Maximum (LGM). 14C dating of high-lake deposits, which are extensively developed along the margins of Lake Cowan, suggested a significant high-lake event during the early to mid-Holocene. The late Quaternary eolian and lacustrine evidence of palaeoenvironmental changes supports the model that during the Last Glacial Maximum, the subtropical high-pressure cell intensified and probably shifted southward, displacing the southern westerlies.
Saline lakes present a range of habitats for study as rich in scientific potential as in the beauty they often display. An extraordinary array of physical, chemical and biological diversity in basins throughout the continent combines with a rich variety of landscape settings; even the dry and apparently desolate salt encrusted ‘lakes’ (salinas) of inland Australia possess their own harsh but enticing appeal.
Variations in lithology and coral assemblages in drill cores from outer- and inner-shelf reefs are used to characterize the Pleistocene development of the Great Barrier Reef. Based on petrographic, isotopic and seismic characteristics, the outer-shelf core from Ribbon Reef 5 is divided into three sections: (1) a main reef section from 0 to 96 m is composed of six reef units, (2) a rhodolith section from 96 to 158 m is interbedded with two thin reef units and (3) a basal section from 158 to 210 m is composed of non-reefal skeletal grainstones and packstones. Two distinct coral assemblages identified in this core represent a shallow, high-energy community and lower-energy community. These two assemblages are repeated throughout the main reef section, with some units recording transitions between assemblages, and others composed of only a single assemblage. These coral assemblage data also correlate with transitions recorded by coralline algae. Using similar criteria, the inner-shelf core from Boulder Reef is divided into two sections: (1) an upper carbonate-dominated section from 0 to 34 m is comprised of four reef units and (2) an underlying mud section from 34 to 86 m is composed of siliciclastics and two thin, coral-bearing units. The four reef units in the upper section are dominated by a single coral assemblage representing a community typical of low energy, turbid environments. Taken together, these data indicate that: (1) reef growth on the inner shelf initiated later than on the outer shelf, (2) true reef ‘turn-on’ in outer shelf areas, as represented by the main reef section in Ribbon Reef 5, was preceded by a transitional period of intermittent reef development and (3) the repeated occurrence of similar coral assemblages in both drill cores indicates that the Great Barrier Reef has been able to re-establish itself, repeatedly producing reefs of similar composition over the last 500 ky, despite major environmental fluctuations in sea level and perhaps temperature.
Monsoon rains in the Kimberley region feed an interconnected chain of lake basins, the Gregory Lakes system in northwestern Australia, a terminal system surrounded by dunefields of the Great Sandy Desert.This semi-arid region records a sequence of Quaternary climatic changes, at times much wetter, at times much drier than today.A morphostratigraphic sequence defines episodic formation of dunes and related sediments reflecting past hydrologic and climatic changes which caused them.Thermoluminescence dating provides a broad temporal framework identifying major hydrologic changes of the past 300 ka.Ancient foreshore dunes define shorelines of mega-lake phases, the largest of which covered some 6500 km2 with ages near 300 ka. Later lacustral expansions near 200 and 100 ka, reflect wet phases broadly comparable to marine isotope stages 7 and 5 with a trend towards increasing aridity through time.Longitudinal quartz dune formed within the mega-lake confines between successive wet phases with at least two dune building episodes near (or just before) 230 and 70 ka.Monsoon activity today produces short-lived flood events such as recorded in 1993. Climates of the mega-lake phases need not be drastically different from today's although a substantial increase in the frequency of high magnitude events was certainly involved.
The fluctuation in primary production and mineral dust accumulation was estimated to better understand marine and terrestrial environments in the Tasman Sea, southwest Pacific, during the Late Pleistocene. Maxima in primary production were observed during late Oxygen Isotope Stage (OIS) 2, middle OIS 4 and late OIS 6 for core NGC 97 while minimum values were observed in OIS 5. On the other hand, primary production was low and relatively uniform in cores NGC 100 and 99 during the last 180 kyr. These results suggest that the Tasman Front existed between NGC 99 (∼30°S) and NGC 97 (∼35°S) during the last 180 kyr and migrated northward by a few degree (∼2–3° latitude) in OIS 2 and 4. The mass accumulation rates (MARs) of mineral aerosol (MARaerosol) estimated from the Al concentration increased southward during each OIS (excluding OIS 2 in cores NGC 100 and 99). The MARaerosol was more enhanced during glacials than interglacials in cores NGC 100 and 97 while NGC 99 showed no definite fluctuation. These results suggest small northward shifts (∼2–3° latitude) of the high pressure subtropical ridge, dividing the tropical easterly circulation from the mid-latitude westerlies, took place during glacial times. These results demonstrate that the boundary between subtropical and temperate features in both ocean and atmosphere consistently migrated by a few degrees between glacials and interglacials. In addition, profiles of MAR of organic carbon, biogenic opal and primary productivity were quite similar for cores NGC 97 and S2612 (32°19.84′N, 157°51.00′E), which shows that the boreal and austral transition zones between subtropical and subarctic waters migrated almost synchronously along the latitudinal transect around 160°E during the last 150 kyr [Kawahata et al., J. Oceanogr. 55 (1999) 521–532]. Therefore boreal and austral mid-latitudes could have probably experienced similar fluctuations in the oceanic and atmospheric environments.
The flux of aeolian dust from Australia to Sediments of the Tasman Sea has increased during glacial stages of the last four glacial cycles. Low fluxes of dust from Australia before 350 ka were followed by an increase in stage 10 and high fluxes in peak glacial periods thereafter. The initiation of higher dust fluxes in stage 10 is consisten with previous estimates of the age of onset of aridity in the source area. Dust flux to the Tasman Sea is thought to record the intensity of deflation from the source area in interior southeastern Australia which was marked by arid conditions and possibly greater windiness during the last glacial.A transect of five cores from the central Tasman Sea revealed consistently low dust fluxes north of 33°S, increasing southward to approximately 40°S. Glacial to interglacial movement of the northern boundary of the dust plume, governed by the position of the subtropical ridge, was less than 6° latitude, probably closer to 3° (350 km). The position of the dust plume determined in this study, and its response to climate change, are significantly different from a previous reconstruction based on the measurement of quartz content of the non-biogenic sediment fraction.
A late Quaternary marine palynological record from the Ocean Drilling Program (ODP) site 820, adjacent to the humid tropics region of northeastern Australia, has demonstrated marked variation in orbital scale cyclicity, and also trends associated with both climate and human impact. However, some uncertainties in interpretation have resulted from concerns about the records chronology and continuity. Here we present, for the first time, the complete palynological data from detailed analysis of the top 67 m of sediment and examine it in relation to the marine isotope sequence from the core. It is proposed that the record is relatively continuous through the last 250,000 years although the latter part of oxygen isotope stage (OIS) 5, as well OIS 4 may be missing. Despite the variation on orbital scales, most palynological changes are not in phase with those from the marine isotope record suggesting a lack of direct Milankovitch forcing on vegetation. This lack of correspondence combined with major trends towards more open and sclerophyllous vegetation in association with increased burning supports a previous proposal that major control is being exercised by El Niño-Southern Oscillation variability whose influence may have been initiated by changes in oceanic circulation in the region within the mid Pleistocene. The lack of impact on the distribution of complex rainforest suggests that increased climate variability did not involve an overall decrease in total precipitation.
The derivation of a detailed sea-surface paleotemperature curve for the middle Miocene-Holocene (10-0 Ma) from ODP Site 811 on the Queensland Plateau, northeast Australia, has clarified the role of sea-surface temperature fluctuations as a control on the initiation and development of the extensive carbonate platforms of this region. This curve was derived from isotopic analyses of the planktonic foraminifer Globigerinoides ruber, and converted to temperature using the surface-water paleotemperature equation accounting for variations in global ice volume. The accuracy of these data were confirmed by derivation of paleotemperatures using the water column isotopic gradient (Δδ¹³O), corrected for salinity and variations in seafloor water mass temperature.
Between 2.5 Ma and 0.7 Ma a Plio-Pleistocene megalake, Lake Bungunnia, existed in the western Murray Basin, Australia. Study of hydrologic and geologic constraints on this lake has enabled the climate of southeastern Australia during the late Pliocene and early Pleistocene to be partly quantified. Modelling shows that Lake Bungunnia could not exist under current climatic conditions, and that an average rainfall of at least 500 mm yr−1 over the catchment of the Murray-Darling river system was likely, considerably more than at present. Minor changes in climate caused large fluctuations in the shoreline of the shallow lake, which are reflected in the geologic record. Possible histories for Lake Bungunnia are suggested in the light of this evidence. Demise of the megalake heralded the onset of aridity in southern Australia, and modern landforms date from that time. Salt lakes in part of the western Murray Basin may have directly descended from Lake Bungunnia.
Alkenone palaeothermometry has demonstrated a wide spatial and temporal applicability for the reconstruction of sea-surface temperatures (SST). Some oceanic realms, however, remain poorly studied. We document U37K' index data for two sediment cores retrieved from the South Tasman Sea, one west of New Zealand (SO136-GC3) and the other southeast of Tasmania (FR1/94-GC3), extending back 280 kyr BP for the former and 460 kyr BP for the latter. High climatic sensitivity on orbital time scales is observed at both locations, particularly west of New Zealand, where typical glacial/interglacial SST amplitudes always span more than 7 °C. Southeast of Tasmania, SST amplitudes are lower in amplitude (4.3 to 6.9 °C) with the exception of Termination IV, which involved a SST change over 8 °C. The evolution of maximum glacial cooling through time is different at each location. Offshore New Zealand, maximum cooling during glacial stages increases with time, whereas south of Tasmania maximum cooling decreases with time. In addition, our data suggest heterogeneity in the spatial expression of SST during the penultimate and last glacial stages. These glacial periods are recorded differently in both areas, with Marine Isotopic Stage 6 being warmer than Marine Isotopic Stage 2 west of New Zealand, but slightly colder southeast of Tasmania. The area southwest of New Zealand appears susceptible to expansions and contractions of the Western Pacific Warm Pool and/or meridional migrations and changes in intensity of currents associated with the Tasman Front. The region southeast of Tasmania seems more sensitive to thermal changes as seen at high southern latitudes.
Four pollen and charcoal records derived from marine cores around the northern perimeter of Australia are examined to provide a regional picture of patterns, causes and impacts of climate change over the last 100–300 ka. The availability of radiocarbon dates and oxygen isotope records for the cores provides primary chronological control. Spectral analysis of components of these records demonstrates an overall importance of Milankovitch frequencies with clear glacial–interglacial cyclicity dominated by variation in precipitation. In addition, a number of pollen taxa, as well as charcoal particles, exhibit a 30 ka frequency that is considered, from its relationship with biomass burning and with results of past modelling, to reflect changes in the intensity of El Niño-Southern Oscillation (ENSO) variability. Pollen components of all records show a decline, frequently stepwise, in more fire-sensitive vegetation and its replacement with more fire-tolerant vegetation. There is some evidence that this trend is linked to an onset or general increase in ENSO activity and perhaps also to variation in monsoon activity dating from about 300 ka BP that was caused by changes to oceanic circulation within the Indonesian region. The trend may have accelerated within the last 45 ka due to burning by indigenous people.
Lake Lewis is the furthest from the coast of Australia's salt lakes and lies at the southern edge of influence of the Australian monsoon regime. The MacDonnell Ranges south of the lake intercept moist air masses crossing the region and efficiently deliver water and sediment to the lake and its surrounding alluvial plain. We describe lacustrine, fluvial and aeolian environments of the basin and report optically stimulated luminescence (OSL) dates from representative sediments. A long period of generally wetter conditions during most of the Pleistocene is represented by thick uniform lacustrine clay beneath and near Lake Lewis. This is overlain by more heterogeneous lacustrine sediments deposited since hydrologic closure of the basin, which indicate fluctuating climatic conditions. OSL results show that dune building in the basin commenced before 95 ka, when salinity at the depocentre was high. Dune building peaked around 23–21 ka. OSL ages of fluvial deposits show that floods occurred during the last 20 ka, following the last phase of maximum aridity in the region.
Resolving faunal responses to Pleistocene climate change is vital for differentiating human impacts from other drivers of ecological change. While 90 % of Australia's large mammals were extinct by ca. 45 ka, their responses to glacial-interglacial cycling have remained unknown, due to a lack of rigorous biostratigraphic studies and the rarity of terrestrial climatic records that can be related directly to faunal records. We present an analysis of faunal data from the Naracoorte Caves in southeastern Australia, which are unique not only because of the species richness and time-depth of the assemblages that they contain, but also because this faunal record is directly comparable with a 500 k.y. speleothem-based record of local effective moisture. Our data reveal that, despite significant population fluctuations driven by glacial-interglacial cycling, the species composition of the mammal fauna was essentially stable for 500 k.y. before the late Pleistocene extinctions. Larger species declined during a drier interval between 270 and 220 ka, likely reflecting range contractions away from Naracoorte, but they then recovered locally, persisting well into the late Pleistocene. Because the speleothem record and prior faunal response imply that local conditions should have been favorable for megafauna until at least 30 ka, climate change is unlikely to have been the principal cause of the extinctions.
Summary 1. Ice-volume forced glacial–interglacial cyclicity is the major cause of global climate variation within the late Quaternary period. Within the Australian region, this variation is expressed predominantly as oscillations in moisture availability. Glacial periods were substantially drier than today with restricted distribution of mesic plant communities, shallow or ephemeral water bodies and extensive aeolian dune activity.
2. Superimposed on this cyclicity in Australia is a trend towards drier and/or more variable climates within the last 350 000 years. This trend may have been initiated by changes in atmospheric and ocean circulation resulting from Australia's continued movement into the Southeast Asian region and involving the onset or intensification of the El Niño-Southern Oscillation system and a reduction in summer monsoon activity.
3. Increased biomass burning, stemming originally from increased climatic variability and later enhanced by activities of indigenous people, resulted in a more open and sclerophyllous vegetation, increased salinity and a further reduction in water availability.
4. Past records combined with recent observations suggest that the degree of environmental variability will increase and the drying trend will be enhanced in the foreseeable future, regardless of the extent or nature of human intervention.
A detailed record of the deglaciation history of the penultimate glacial to interglacial transition is given, mainly based on the stable isotopes of calcium carbonate-containing lake sediments in a glacially excavated depression below the city of Amsterdam. Initially, this depression, the Amsterdam Basin, formed part of a lake covering the western and central part of the Netherlands and extending for an unknown distance into the present North Sea. Annual layer counting shows that the lake drained after about a millennium, leaving shallow pools in the remaining depressions. The latter changed again into larger and deeper lakes including the Holland Lake during the rise of sea level in the early Eemian. Oxygen isotope values of the early lake sediments indicate an interglacial summer climate, but the nearness of dead-ice fields caused severe winters. The isotope record is furthermore characterized by the influx of large amounts of isotopically light water supplied by the river Rhine. A change to much colder conditions occurred simultaneously with the draining of the Holland Lake, as appears from oxygen isotope values and the sudden increase in non-arboreal pollen. This interval is correlated with the Kattegat Stadial and the sea-level standstill of Aladdins Cave on the Huon Peninsula of New Guinea. A short climate wiggle occurs at the end of this interval. The onset of the Eemian is marked by a rapid warming of 5°C which extends into local pollen-zone E3. Provided that our correlation of this cold interval with the sea-level standstill of Aladdins Cave is correct, the time interval between the earliest lake sediments in the Amsterdam Basin and the Eemian highstand took about 5–6 millennia. Yes Yes
The Antarctic Vostok ice core provided compelling evidence of the nature of climate, and of climate feedbacks, over the past 420,000 years. Marine records suggest that the amplitude of climate variability was smaller before that time, but such records are often poorly resolved. Moreover, it is not possible to infer the abundance of greenhouse gases in the atmosphere from marine records. Here we report the recovery of a deep ice core from Dome C, Antarctica, that provides a climate record for the past 740,000 years. For the four most recent glacial cycles, the data agree well with the record from Vostok. The earlier period, between 740,000 and 430,000 years ago, was characterized by less pronounced warmth in interglacial periods in Antarctica, but a higher proportion of each cycle was spent in the warm mode. The transition from glacial to interglacial conditions about 430,000 years ago (Termination V) resembles the transition into the present interglacial period in terms of the magnitude of change in temperatures and greenhouse gases, but there are significant differences in the patterns of change. The interglacial stage following Termination V was exceptionally long—28,000 years compared to, for example, the 12,000 years recorded so far in the present interglacial period. Given the similarities between this earlier warm period and today, our results may imply that without human intervention, a climate similar to the present one would extend well into the future.