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Eocene palaeogeography of the south polar region with a cladogram of australobatrachid frogs showing their occurrences on the southern continents. The grey color indicates the outlines of the continents during the Eocene, the black colored outline the present-day outlines of the continents. Map redrawn from an original generated using ArcGIS 10.17.1 (www.esri.com) software, based on the Satellite base map layer in google Maps (Map data ©2019 Google). Abbreviations: ANT, Antarctica; AUS, Australia and Tasmania; NG, New Guinea; NZ, New Zealand; SA, South America. The red star indicates the fossil locality on Seymour Island.
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Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first m...
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... is at least as old as early Eocene, based on fragmentary ilia that were referred to the basal extant Lechriodus 58 . The split between Calyptocephalellidae and Myobatrachidae (Calyptocephalellidae + Myobatrachoidea sensu 27 ) occurred ~100 Ma (~Early-Late Cretaceous boundary) 59 . Considering the distributions of extant Australobatrachia (Fig. 5), the earliest fossil records 10 and the divergence age (from genetic data) 59 of both Calyptocephalellidae and Myobatrachoidea lineages, it is clear that Antarctica had played an important palaeobiogeographic role for Australobatrachia and their consequent dispersal. Because the most recent common ancestor of the clade, including ...
Citations
... Beyond the resistome, remote environments have also been recognized for their potential to host novel pathogens and virulence factor genes (VFGs) (He et al., 2022;Kim et al., 2022). Moreover, before Antarctica froze more than 10 million years ago, it had a temperate to sub-tropical climate with rainforest environments hosting several plant and animal species, including Nothofagus trees, dinosaurs, amphibians, and ancient mammals (Defler, 2019;Kloess et al., 2020;Mörs et al., 2020;O'Gorman et al., 2019;Vento et al., 2022). Thus, bacterial pathogens associated with these organisms likely existed in several areas of Antarctica, some potentially remaining under the ice for millions of years. ...
The high-latitude regions of Antarctica remain among the most remote, extreme, and least explored areas on Earth. Despite the highly restrictive conditions, microbial life has been found in these environments, although with limited information on their genetic properties and functional capabilities. Moreover, the accelerated melting of the Antarctic permafrost, the increasing exposure of soils, and the growing human transit pose the question of whether these environments could be a source of microbes or genes that could emerge and cause global health problems. In this line, although a high bacterial diversity and autochthonous multidrug-resistant bacteria have been found in soils of the Antarctic Peninsula, we still lack information regarding the resistome of areas closer to the South Pole. Moreover, no previous studies have evaluated the pathogenic potential of microbes inhabiting Antarctic soils. In this work, we combined metagenomic and culture-dependent approaches to investigate the microbial diversity, resistome, virulome, and mobile genetic elements (MGEs) in soils from Union Glacier, a high-latitude cold desert in West Antarctica. Despite the low organic matter content, diverse bacterial lineages were found, predominating Actinomycetota and Pseudomonadota, with limited archaeal and fungal taxa. We recovered more than 80 species-level representative genomes (SRGs) of predominant bacterial taxa and the archaeon Nitrosocosmicus sp. Diverse putative resistance and virulence genes were predicted among the SRGs, metagenomic reads, and contigs. Furthermore, we characterized bacterial isolates resistant to up to 24 clinical antibiotics, mainly Pseudomonas , Arthrobacter , Plantibacter, and Flavobacterium . Moreover, some isolates produced putative virulence factors, including siderophores, pyocyanins, and exoenzymes with hemolytic, lecithinase, protease, and DNAse activity. This evidence uncovers a largely unexplored resistome and virulome hosted by deep Antarctica’s soil microbial communities and the presence of bacteria with pathogenic potential, highlighting the relevance of One Health approaches for environmental surveillance in the white continent.
HIGHLIGHTS
-Union Glacier soils host a microbial community dominated by bacteria, mainly from the phylum Actinomycetota.
-Archaea from the Nitrosocosmicus genus (family Nitrosphaeraceae) were ubiquitously detected.
-Although extreme and remote, these soils host multidrug-resistant and potentially pathogenic bacteria. Some were cultured and tested in vitro .
-Metagenomes and species-level representative genomes revealed diverse putative resistance and virulence genes.
-Part of the putative antimicrobial resistance genes and virulence factors could be associated with mobile elements in bacterial genomes.
... Seymour Island, situated off the eastern tip of the northern Antarctic Peninsula, is a relatively small island in the James Ross Basin. Seymour Island is known for its abundant fossil discoveries, including vertebrates like fishes, aquatic birds, and frogs (Acosta Hospitaleche et al., 2019a;Reguero, 2019;Mö rs et al., 2020), invertebrates such as echinoderms, mollusks, corals, and decapods (Feldmann, 1989;Stolarski, 1996;Blake and Aronson, 1998), as well as plants (Cantrill et al., 2011) and microfossils like foraminifera and ostracods (Gaździcki and Majewski, 2012). Seymour Island contains a diverse range of sedimentary strata, spanning from the Upper Cretaceous to the Pliocene (Montes et al., 2019). ...
Eocene penguins from Seymour Island play an important role in studies related to the taxonomy and evolution of the Sphenisciformes stem group. Among these penguins, the Palaeeudyptes species are particularly noteworthy for their unusually large size and the contentious nature of their classification criteria. In this study, we describe a new penguin skeleton with a well-preserved tarsometatarsus discovered in the Upper Eocene of Seymour Island, Antarctica. The new fossil exhibits the tarsometatarsal characteristics of Palaeeudyptes but differs from two species of Palaeeudyptes previously found on Seymour Island, providing insights on the morphological diversity and evolutionary history of early penguins. We conducted normality and unimodality tests on Palaeeudyptes taxa from Seymour Island to reassess the hypothesis that size differences between the two species of this genus could be attributed to sexual dimorphism in a single species. The results revealed that size differences are unlikely due to sexual dimorphism. We also use linear discriminant analysis to evaluate the taxonomic criteria for the two Palaeeudyptes species discovered in the Antarctic region. The data showed an overlap in the size distribution, indicating weakness in the classification criteria. Reassessing previous samples and establishing an additional diagnosis based on critical anatomical features could potentially resolve this issue.
... In the past, changes in the climate and geology affected the distribution of the biota, in amphibians exist biogeographical studies with the presence of fossil frogs that are extinct in those sites. For example, the fossil record of the helmeted water toad Calyptocephalella in the Eocene (∼ 40 million years old) from Antarctica (Mörs et al. 2020), is the first fossil record of amphibians in Antarctica and the distribution range of the genus Calyptocephalella is in lowlands from central Chile currently (Mora et al. 2021). The presence of the helmeted water toad in Antarctica allowed the reconstruction of the paleoclimate in the area. ...
... The presence of the helmeted water toad in Antarctica allowed the reconstruction of the paleoclimate in the area. For this, Mörs et al. (2020) analyzed the climatic parameters of selected stations from the current distribution range of Calyptocephalella gayi and the Colocolo opossum Dromiciops gliroides, both species found in the fossil site. They inferred the mean annual precipitation ≥ 900 mm, the (2018,2021). ...
... Drawn by Gerardo García Demeneghi coldest month mean temperature ≥ 3.75 °C, and the warmest month mean temperature ≥ 13.79 °C. Additionally, they inferred the presence of freshwater ecosystems in Antarctica as favorable habitats for Calyptocephalella (Mörs et al. 2020). ...
The reproductive and physiological amphibians’ needs are strongly influenced by rainfall and water availability. Temperature is another important factor in amphibian survival. Amphibians, as well as reptiles, are ectothermic. Amphibians are dependent on external heat sources for thermoregulation, processes of distribution underlying speciation, dispersal, and local extinction vary according to climate factors. However, the ecological traits in extant amphibians have been poorly used in palaeoecological studies. For example, the use of relationship between size and temperature has allowed us to reconstruct the paleoclimate in the Cretaceous or infer how climate changes directly affect the size of anurans. In the past, changes in the climate and geology affected the distribution of the amphibians, the presence of fossil frogs in paleontological and archaeological sites indicates changes in the range of this organism that are extinct in those sites. With salamanders’ studies about the effect of the precipitation on the distribution range of the past or paleoclimatic reconstruction using the phylogeny have been carried out. In Mexico, only exist one quantitative study to paleoenvironmental reconstruction using mainly axolotls. Therefore, carrying out paleontological, archaeological, and osteological studies with these organisms is necessary.
... Most of the latter groups are lacking from the fossil record, with the exception of telmatobiids, which have recently been described from the late Middle Miocene of the Bolivian Altiplano . Conversely, Australobatrachia, which is an ancient lineage with a nowadays disjoint distribution in Chile and Australia (AmphibiaWeb 2023), has a widespread Late Cretaceous -Palaeogene calyptocephalellid record in Patagonia and Antarctica (Muzzopappa and Báez 2009;Gómez et al. 2011;Mörs et al. 2020;Nicoli et al. 2022;Suazo Lara and Gómez 2022) and, thus, it is expected that several fossils from the Palaeogene of Patagonia would represent this group. ...
Frogs (Anura) are major components of tetrapod communities in the Neotropics and, according to divergence-time estimates, were already diverse in early Palaeogene times, but this is still poorly documented in the fossil record. A late Eocene frog assemblage from the Geste Formation exposed at Antofagasta de la Sierra (Catamarca province) is here described, providing a first glimpse into the Palaeogene anuran diversity in the present-day Puna of north-western Argentina. The assemblage is composed by at least four hyloid neobatrachian taxa having miniature to large body-sizes, ranging 17–81 mm estimated snout-vent length. Neither the families currently found in the Puna-Altiplano, nor those from the Cretaceous – Eocene of southern South America, are represented. The assemblage comprises possible brachycephaloids, odontophrynids, and hemiphractids, suggesting climatic and environmental conditions very different from the harsh conditions prevailing today in the Puna-Altiplano and a biogeographical link with Amazonia. The joint presence of these taxa is currently restricted to the nearby Austral Yungas and the Atlantic Forest, suggesting that the late Eocene frogs likely inhabited a humid forest. The new frog assemblage constitutes a rare window to the early evolution of Neotropical anurans and a major leap forward in the palaeoenvironmental reconstruction of the Puna during Eocene times.
... Our model results show mild and perennially wet conditions in Antarctic coastal regions, which would support a cool temperate (Nothofagus) forest or sub-tropical vegetation. This is in agreement with available temperature and precipitation reconstructions for the middle Eocene Wilkes Land East Antarctic Margin (Pross et al., 2012;Contreras et al., 2013), Seymour Island (Dutton et al., 2002Douglas et al., 2014;Mörs et al., 2020), andPrydz Bay (Tibbett et al., 2021). The regional occurrence of paratropical vegetation in the early-middle Eocene is supported by our 4× Eocene cases. ...
Understanding the extreme greenhouse of the Eocene (56–34 Ma) is key to anticipating potential future conditions. While providing an end member towards a distant high-emission scenario, the Eocene climate also challenges the different tools at hand to reconstruct such conditions. Besides remaining uncertainty regarding the conditions under which the large-scale glaciation of Antarctica took place, there is poor understanding of how most of the continent remained ice free throughout the Eocene across a wide range of global temperatures. Seemingly contradictory indications of ice and thriving vegetation complicate efforts to explain the Antarctic Eocene climate. We use global climate model simulations to show that extreme seasonality mostly limited ice growth, mainly through high summer temperatures. Without ice sheets, much of the Antarctic continent had monsoonal conditions. Perennially mild and wet conditions along Antarctic coastlines are consistent with vegetation reconstructions, while extreme seasonality over the continental interior promoted intense weathering shown in proxy records. The results can thus explain the coexistence of warm and wet conditions in some regions, with small ice caps forming near the coast. The resilience of the climate regimes seen in these simulations agrees with the longevity of warm Antarctic conditions during the Eocene but also challenges our view of glacial inception.
... Calyptocephalella gayi (the Chilean giant frog) and Telmatobufo (four species, Mountain false toads) comprise the family Calyptocephalellidae, one of the most ancient anuran lineages from South America (Feng et al. 2017). This family, endemic to south-central Chile (western side of the Andes), is more related to the Australasian family Myobatrachidae than to any South American lineage, which is consistent with a Gondwanan origin (Correa et al. 2008;Mörs et al. 2020). The family has a rich fossil record, mainly in Argentinean Patagonia, where several extinct species of the genus Calyptocephalella have been described (reviewed by Nicoli et al. 2022), but no fossils of the genus Telmatobufo are known. ...
Telmatobufo venustus was one of the rarest endemic amphibians of Chile until 2020. Prior to that year, this species had been known in four localities, three of them with uncertain location, including the type locality. However, three new precise localities have been reported successively since 2020, all based on a few individuals. In this study, we review the geographic information on the species and, based on literature and other documents, tentatively locate the three localities with uncertain location published before 2020. Furthermore, we describe a new locality near the uncertain southern end of its distribution. Although the number of localities has considerably increased since 2020, the species still has a highly fragmented known distribution, its type locality and southern limit cannot be located with certainty, and it is found in only two state-protected areas. Due to these reasons and because threats to the habitat have been identified in some localities, we suggest keeping the species as Endangered.
... Amphibians persist on every continent except Antarctica (although they historically occurred there; see Mörs et al. 2020) and the high Arctic. More than 815 amphibian species are reported from continental Africa (Channing & Rödel 2019), a number that is expected to grow in the coming years due to new species discoveries. ...
The amphibians of the highlands and escarpments of Angola and Namibia are a diverse group containing fifteen highland endemic or associated species. Both species richness and endemism are highest in the central and northern highlands of Angola, corresponding with higher rainfall. The Angolan highlands contain seven highland endemics, while the arid Namibian highlands contain only one. Few baseline data are available for much of the highlands, leading to an inadequate understanding of species occurrence patterns, population trends and conservation status. Recent surveys and phylogenetic revisions have led to the discovery of several previously undescribed species, and new species descriptions are still in progress. Both the species richness and endemism reported here are probably underestimates.
... In other words, vicariance can be assumed to be the cause of the southern temperate disjunction of some Gondwanan stem groups, caused by events that occurred only during the Eocene (Ye et al. 2019). These trans-Antarctic connections (Amorim et al. 2009), enabled by the warm climate from the mid-Cretaceous to the end of the Eocene, have been demonstrated to have occurred in bees (Almeida et al. 2012), bee flies (Lamas & Nihei 2007;Márquez-Acero et al. 2021), tabanid flies (Lessard et al. 2013), orchids (Givnish et al. 2016), frogs (Mörs et al. 2020), fungus gnats (Oliveira & Amorim 2021) and temperate lowland rainforests elements (Klages et al. 2020). The Pelecorhynchidae species seem to have had a relatively wide distribution on the planet since the Middle Jurassic, when Gondwana began to break up (165-150 Ma) (Sanmartín & Ronquist 2004). ...
The phylogeny of the genus Pelecorhynchus Macquart (Diptera: Pelecorhynchidae) was analyzed using three genes, cytochrome oxidase I, 28S ribosomal DNA, and CAD5, with 112 morphological characteristics. A total of 59 specimens (13 outgroups and 46 ingroups) were included in the analysis. The monophyly of Pelecorhynchidae was recovered under all analyses, with Glutops Burgess as the sister group of Pelecorhynchus s.l., while Pseudoerinna jonesi (Cresson) was the sister group. Within “Pelecorhynchus” there are three main clades with unresolved affinities. Clade I was formed by P. personatus (Walker), P. vulpes (Macquart), P. penai Pechuman and P. kroeberi (Lindner), a well-supported clade. Clade II corresponds to the set of species of “Chilean Pelecorhynchus”, conformed to P. biguttatus (Philippi), P. toltensis Llanos & González, P. elegans (Philippi), P. xanthopleura (Philippi), P. hualqui Llanos & González, and P. longicauda (Bigot), a well-supported clade. Clade III is represented exclusively by P. fulvus Ricardo, which has an exclusively Australian distribution. The monophyly of P. fulvus and its nomenclature remain an open question, as only a single species of this taxon was included. Our study demonstrated that the concept of Pelecorhynchus should be revisited. Therefore, we restore Coenura Bigot, 1857 to generic status for part of the southern South American species of “Pelecorhynchus” conformed by the species C. biguttata, C. elegans, C. hualqui, C. longicauda, C. toltensis, and C. xanthopleura which are monophyletic, supported by molecular and morphological data, and consistent with a Chilean distribution.
... We decided on a set of 10 measurements (Supporting Information, Fig. S3) that could often be measured on the various fragmentary fossils represented in our sample. Four of these measurements have been used in the past to estimate the body length of fossil anurans: the acetabular height (Pratt 1986), the 'height of the transition (HT) from the iliac shaft and ilial body' (Mörs et al. 2020) that is similar to our measure of pre-acetabulum ilium width (paiw, Fig. S3), and both humeral head width and total width of the distal humerus , Martínez-Monzón et al. 2022. We took measurements on the region of interest of segmented bones on the CT-scans of specimens using the Polyline length tool on VG Studio Max v.3.5 (Supporting Information, Table S2). ...
... To estimate body size as SUL, we used a set of measurements from five different skeletal elements (radioulna, humerus, sacrum, ilium, and urostyle), some of which have been previously suggested or used in the literature (Pratt 1986, Mörs et al. 2020, Martínez-Monzón et al. 2022). All of these measurements are good proxies to estimate SUL in fossil Eleutherodactylus. ...
Establishment of extant terrestrial vertebrate faunas in North America was influenced by a set of factors associated with temporal changes in climate and ecology that operated at different geographic scales. While the biogeography of extant taxa can be inferred from phylogenies, these omit lineages that have gone regionally extinct and for which the only direct evidence is the fossil record. A comprehensive study of anurans from the Late Oligocene of Florida reveals an abundance of fossils referred to Eleutherodactylus. Time-calibrated molecular phylogenies have suggested that this genus originated in the Caribbean in the Early Oligocene and then colonized Central America in the Middle Miocene. Here, we describe the first records of pre-Quaternary fossils referred to Eleutherodactylus from Florida. Results from analysis of inter- and intraspecific variation in anatomy, size, and shape of isolated bones of fossil and extant species suggest that the fossils represent adult individuals with an estimated body size (snout–urostyle length) of 16.8–29.8 mm. We show that Eleutherodactylus was established by the Late Oligocene in North America well before colonizing Central America in the Miocene. We provide, for the first time, evidence of dispersal of amphibians from the Caribbean into North America during the Late Oligocene.
... . Of these, the ilium is the most taxonomically informative and has been used for frog taxonomic studies worldwide (Báez et al., 2012;Blain et al., 2015;Evans & Borsuk-Białynicka, 2009;Evans et al., 1990;Folie et al., 2012;Gómez & Turazzini, 2016;Gómez et al., 2013;Holman, 1959Holman, , 2003Mörs et al., 2020;Roček et al., 2013;Tyler, 1976). These studies have successfully demonstrated that the ilium can be used to diagnose different groups of fossils and living frogs globally. ...
Anurans including frogs and toads exhibit an ilium that is often regarded as taxonomically diagnostic. The ilium, one of the three paired bones that make up the pelvic girdle, has been important in the fossil record for identifying anuran morphotypes. Osteological collections for Australian frogs are rare in herpetological museums, and skeletonizing whole-bodied specimens requires destroying soft tissue morphology which is valuable to anuran specialists working on living species. Computed tomography scans provide the opportunity to study anuran osteology without the loss of soft tissues. Our study, based on microcomputed tomography scans of extant Australian frogs from the public repository Morphosource and from museum collections focuses on the morphological differences between Australian frogs at the familial and generic levels using geometric morphometrics to compare the diagnostic shape of the ilium. Principal component analysis (PCA) and canonical variate analysis (CVA) were conducted to assess differences in the ilium between supraspecific groups of Australian frogs. The canonical variates analysis accurately predicted group membership (i.e., the correct family) with up to 76.2% success for cross-validated predictions and 100% of original group predictions. While the sample was limited to familial and generic level analyses, our research shows that ilial morphology in Australian frogs is taxonomically informative. This research provides a guide for identifying Australian anurans, including fossils, as well as new information relevant to considerations about their phylogenetic relationships, and the potential use of the fossil record to enhance efforts to conserve threatened living frog species.
