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Long-term stasis in a diverse fauna of Early Cretaceous springtails (Collembola: Symphypleona)
Abstract
Springtails (Hexapoda: Entognatha: Collembola) extend into at least the Early Devonian, but have a meagre record as fossils until the latter part of the Mesozoic. Here, we document a diverse fauna of springtails in the order Symphypleona from amber recovered at the Peñacerrada I locality, Moraza, northern Spain, and from the Late Albian Utrillas Group in the Basque-Cantabrian Basin. The fauna includes representatives of all of the principal suborders and infraorders, and most superfamilies, of the Symphypleona. This revision of the fauna includes the discovery and description of five new genera and species scattered across the phylogenetic diversity of the clade: Pseudosminthurides stoechus gen. et sp. nov. (Sminthurididae), Cretokatianna bucculenta gen. et sp. nov. (Katiannidae), Sphyrotheciscus senectus gen. et sp. nov. (Sminthuridae: Sphyrothecinae), Archeallacma dolichopoda gen. et sp. nov. (Sminthuridae: Sminthurinae?) and the enigmatic Katiannasminthurus xenopygus gen. et sp. nov. (Sminthuridae? incertae sedis). This is the earliest amber fauna of springtails yet described, and highlights the remarkably modern character of the group even during the early stages of the Cretaceous.http://zoobank.org/urn:lsid:zoobank.org:pub:BFF73D0D-31A0-4AE1-9CA4-C62424177C7D
... Sminthurididae, along with the monotypic Mackenziellidae, delimit the suborder Sminthuridida, the sister group of all other Symphypleona, the Appendiciphora [6][7][8]. ...
... The authors also dismissed any internal suprageneric subdivisions of the family, a position which was followed by other important revisions [4,5,27], and genera and species descriptions [45,46,[49][50][51]54]. In 1986, Bretfeld [7] proposed a phylogenetic study of the higher taxa of the Symphypleona, suggesting the name Sminthuridida as a synonym of Sminthurididae, which was subsequently used as a suborder of Symphypleona by Sánchez-García and Engel [7], also encompassing the Mackenziellidae. ...
... The authors also dismissed any internal suprageneric subdivisions of the family, a position which was followed by other important revisions [4,5,27], and genera and species descriptions [45,46,[49][50][51]54]. In 1986, Bretfeld [7] proposed a phylogenetic study of the higher taxa of the Symphypleona, suggesting the name Sminthuridida as a synonym of Sminthurididae, which was subsequently used as a suborder of Symphypleona by Sánchez-García and Engel [7], also encompassing the Mackenziellidae. ...
The Sminthurididae family includes Symphypleona species highly adapted to courtship, with males exhibiting remarkable modifications on their antennae. Here we describe a new Neotropical genus and species of Sminthurididae from a Cerrado-Caatinga ecotonal zone in Brazil. Males of Parasminthurides spinosus gen. nov. sp. nov. have highly dimorphic antennal claspers similar to those of Sminthurides, but its females have unique strong spiniform chaetae on antennal segments II and III as well, which are possibly accessories for the courtship. The new genus can also be diagnosed by its elongated maxillae, males having large dorsal vesicles between abdomen II and III, ungues I–III with similar morphology and sizes, and interno-apical dental chaetae modified into large spiniform chaetae. We also present the main diagnostic features of all Sminthurididae genera, providing a comparative table and an updated identification key for them. Finally, we discuss the previous and current knowledge on the family’s systematics, suggesting some perspectives for future studies in this field.
... The bias of the fossil record of springtails towards preservation in amber is not surprising given their lightly sclerotized cuticle, minute size and water-repellant body structures which enhance buoyancy in water surface and prevent preservation as compression fossils (note that only a few collembolan records are in cherts, shale compressions, or calcareous nodules). Despite by the time of amber-producing deposits in the Early Cretaceous and onward the number of springtails preserved is higher [10,11], albeit often of modest species diversity but of considerable phylogenetic breadth in representation, it remains that evidence for behavioral interactions is extremely rare. Rapid entombment and preservation in resin means that individuals can be preserved with life-like fidelity, sometimes even capturing behavioral interactions. ...
... In the males, the antennae are modified for clasping the female during mating and the females lack anal appendages [31]. Among sminthuridids, P. stoechus has a unique combination of traits including a body size about 0.6 mm, a pair of large interocular vesicles, a distinctly tuberculate tibiotarsus, a head and abdomen lacking spines and broadened setae, the 'ABC' bothriotrichia distributed in an oblique line, and characteristic dens and mucro [10]. The antenna of male P. stoechus shows a developed first antennomere, and is modified in the second antennomere to interlock with the third and form a 'clasping organ' (Fig 2A). ...
... The remarkable inclusions reported here showcase the potential that the amber record offers to reconstruct not only the morphology of fossil arthropods but also their ancient life history, behaviors, and broader ecology and habitat. Given that in springtails entire suites of morphological characters are strongly correlated and influenced by their ecology [49], the species reported here and elsewhere [10,11] permit us to infer the local environment in which the resin was exuded. Although pieces of amber from Peñacerrada I largely represent a sampling of taxa from above the forest floor, fossiliferous resins are just as likely to sample soil and litter faunas and even nearby aquatic habitats [50], microenvironments in which modern Collembola are abundant and diverse. ...
Among the many challenges in paleobiology is the inference and reconstruction of behaviors that rarely, if ever, leave a physical trace on the environment that is suitable for fossilization. Of particular significance are those behaviors tied to mating and courtship, individual interactions critical for species integrity and continuance, as well as those for dispersal, permitting the taxon to expand its distribution as well as access new habitats in the face of local or long-term environmental change. In this context, two recently discovered fossils from the Early Cretaceous amber of Spain (ca. 105 mya) give a detailed view of otherwise fleeting ethologies in Collembola. These occurrences are phylogenetically spaced across the class, and from species representing the two major clades of springtails—Symphypleona and Entomobryomorpha. Specifically, we report unique evidence from a symphypleonan male (Pseudosminthurides stoechus Sánchez-García & Engel, 2016) with modified antennae that may have functioned as a clasping organ for securing females during mating on water’s surface, and from an aggregation of entomobryomorphan individuals (Proisotoma communis Sánchez-García & Engel, 2016) purportedly representing a swarming episode on the forest floor. We demonstrate that the mating behavioral repertoire in P. stoechus, which is associated with considerable morphological adaptations, likely implied elaborate courtship and maneuvering for guarantee sperm transfer in an epineustic species. These discoveries reveal significant behaviors consistent with modern counterparts and a generalized stasis for some ancient hexapod ethologies associated with complex mating and courtship and social or pre-social aggregations, so critical to specific constancy and dispersal.
... Concerning the Symphypleona, in all analyses the sampled families were recovered as monophyletic independent groups (Figures 1, 5 and S1-S5). All ML models reached the same results for the order, with the Sminthurididae (suborder Sminthuridida sensu Sánchez-García and Engel [82]) as the sister group of the suborder Appendiciphora sensu Bretfeld [17]. Within the latter group, Dicyrtomidae was found to be the sister group of the Sminthuroidea (Sminthuridae + Bourletiellidae) (Figures 1, 5A and S1-S3). ...
... Nevertheless, our ML trees (Figure 5) support previous hypotheses of the internal relationships of the order. The suborders Sminthuridida and Appendiciphora Bretfeld [17] sensu Sánchez-García and Engel [82] were recovered with high node support in all ML trees, while our tree topology tests recovered mixed results, both supporting Appendiciphora and Sminthuridida, or refuting them as independent taxa (Table S3). The morphology strongly supports the two suborders, as the Sminthurididae and Mackenziellidae (Sminthuridida) share the apomorphic antennal clasper of the males and the plesiomorphic short and spherical ventral tube sacs and absence of the subanal appendages; at the same time, the Appendiciphora, gathering all the other families of Symphypleona s. str., share the derived long ventral tube sacs and the subanal appendage of the females [10,17,21,83]. ...
Mitogenomes represent useful tools for investigating the phylogeny of many metazoan clades. Regarding Collembola, the use of mitogenomics has already shown promising results, but few published works include sufficient taxon sampling to study its evolution and systematics on a broader scale. Here, we present a phylogenetic study based on the mitogenomes of 124 species from 24 subfamilies, 16 families, and four orders—one of the most comprehensive datasets used in a molecular study of Collembola evolution to date—and compare our results with the trees from recently published papers and traditional systematic hypotheses. Our main analysis supported the validity of the four orders and the clustering of Poduromorpha with Entomobryomorpha (the traditional Arthropleona). Our data also supported the split of Symphypleona s. str. into the Appendiciphora and Sminthuridida suborders, and the division of the Neelipleona into two subfamilies: Neelinae and Neelidinae subfam. nov. On the other hand, the traditional Symphypleona s. lat., Isotomoidea, and all the Isotomidae subfamilies were refuted by our analyses, indicating a need for a systematic revision of the latter family. Though our results are endorsed by many traditional and recent systematic findings, we highlight a need for additional mitogenomic data for some key taxa and the inclusion of nuclear markers to resolve some residual problematic relationships.
... Patterns of morphological stasis or 'cryptic speciation' can be driven by directional selection on non-morphological traits such as sexual recognition, physiology, or behavior [24], and/or stabilizing selection resulting from extreme, and possibly invariant, selection pressures [25], but it remains unclear as to why the discordance between genetic and morphological variation is so prevalent in springtails. Populations may have diversified at the molecular level without morphological change over long periods of time, possibly due to invariant selection pressures on morphology [26]. The fossil record supports this 'ancient relic' hypothesis, with many examples of fossils being placed into extant families or genera [26][27][28][29]. ...
... Populations may have diversified at the molecular level without morphological change over long periods of time, possibly due to invariant selection pressures on morphology [26]. The fossil record supports this 'ancient relic' hypothesis, with many examples of fossils being placed into extant families or genera [26][27][28][29]. Alternatively, species with highly genetically structured populations, as is common among springtails, may have an increased probability of mutations reaching fixation, which can lead to accelerated rates of molecular evolution [30]. ...
Previous estimates of nucleotide substitution rates are routinely applied as secondary or "universal" molecular clock calibrations for estimating evolutionary timescales in groups that lack independent timing information. A major limitation of this approach is that rates can vary considerably among taxonomic groups, but the assumption of rate constancy is rarely evaluated prior to using secondary rate calibrations. Here I evaluate whether an insect mitochondrial DNA clock is appropriate for estimating timescales in Collembola-a group of insect-like arthropods characterized by high levels of cryptic diversity. Relative rates of substitution in cytochrome oxidase subunit 1 (COI) were inferred via Bayesian analysis across a topologically constrained Hexapod phylogeny using a relaxed molecular clock model. Rates for Collembola did not differ significantly from the average rate or from the rates estimated for most other groups (25 of 30), suggesting that (1) their apparent cryptic diversity cannot be explained by accelerated rates of molecular evolution and (2) clocks calibrated using "universal" insect rates may be appropriate for estimating evolutionary timescales in this group. However, of the 31 groups investigated, 10 had rates that deviated significantly from the average (6 higher, 4 lower), underscoring the need for caution and careful consideration when applying secondary insect rate calibrations. Lastly, this study exemplifies a relatively simple approach for evaluating rate constancy within a taxonomic group to determine whether the use of secondary rates are appropriate for molecular clock calibrations.
... Patterns of morphological stasis, or 'cryptic speciation', can be driven by directional selection on non-morphological traits such as sexual recognition, physiology, or behavior (Bickford et al., 2007), and/or stabilizing selection resulting from extreme, and possibly invariant, selection pressures (Rothschild & Mancinelli, 2001), but it remains unclear as to why this discordance between genetic and morphological variation is so prevalent in springtails. Populations may have diversified at the molecular level without morphological change over long periods of time, possibly due to invariant selection pressures on morphology (Sánchez-García & Engel, 2016). The fossil record supports this 'ancient relic' hypothesis, with many examples of fossils being placed into extant families or genera (Mari Mutt, 1983;Christiansen & Pike, 2002;Christiansen & Nascimbene, 2006;Sánchez-García & Engel, 2016). ...
... Populations may have diversified at the molecular level without morphological change over long periods of time, possibly due to invariant selection pressures on morphology (Sánchez-García & Engel, 2016). The fossil record supports this 'ancient relic' hypothesis, with many examples of fossils being placed into extant families or genera (Mari Mutt, 1983;Christiansen & Pike, 2002;Christiansen & Nascimbene, 2006;Sánchez-García & Engel, 2016). Alternatively, species with highly genetically structured populations, as is common among springtails, may have an increased probability of mutations reaching fixation, which can lead to accelerated rates of molecular evolution (Frean et al., 2013). ...
Vicariance and dispersal are major drivers of the evolution of biodiversity, yet the relative impact of these processes, and the factors that influence them, often remain elusive. Identifying and understanding evolutionary processes responsible for generating diversity is essential for understanding ecological patterns and for the development and implementation of management strategies intended to conserve biodiversity. My dissertation research is focused on the historical, ecological and evolutionary underpinnings driving the origin, diversification, and maintenance of biodiversity in springtails (Collembola). This class of tiny, wingless insect-like hexapods includes some of the most abundant (and perhaps, most diverse) arthropods on earth. They have colonized, diversified, and adapted to nearly every terrestrial habitat from marine intertidal zones and tropical rainforests to polar deserts and caves, yet the evolutionary mechanisms behind their ecological success are poorly understood.
Ecological specialization is a central theme in my first two chapters. Species with obligate ecological associations offer simple systems to evaluate biogeographical hypotheses and also provide an ecological context to test the effects and consequences of specialization on patterns of diversity. In Chapter 1, I identify and compare spatial and temporal patterns of molecular diversity for two ecologically distinct and codistributed genera of cavernicolous springtails (cave-obligate vs. cave-facultative species) from a regional cave-bearing karst system spanning the Mississippi River in Illinois and Missouri. Phylogeographic analysis revealed that evolutionary processes of vicariance and dispersal were both major influences on patterns of cave springtail diversity, but the effects of these processes are also strongly influenced by intrinsic ecological factors, in this case, the degree of cave-dependence. Estimates of genetic structure and divergence times also implicated climatic and geological processes involved in the formation of the modern Mississippi River valley as major factors driving the isolation of cave-obligate species, but cave-facultative species have been able to maintain genetic connectivity across this barrier.
In Chapter 2, I developed a molecular dataset for marine littoral-obligate springtails collected along the Pacific and Atlantic coasts of Panama to identify transisthmian sister taxa, determine processes driving and maintaining their isolation, and to evaluate their timing of origin. I was able to identify multiple geminate species pairs spanning the Isthmus and molecular analyses revealed examples of pre-Pliocene vicariance, post-closure dispersal, and cryptic diversification across the Isthmus of Panama. This study not only demonstrates that ecological specialization can (but not always) reduce genetic connectivity across geographic barriers, but also corroborates recent (and controversial) geological and biogeographical estimates of an early Miocene closure of the Panama Isthmus.
These works demonstrate the utility of incorporating ecologically specialized springtails in evolutionary investigations. However, independent timing information is essential for assessing historical factors influencing contemporary patterns of diversity. Unfortunately, springtails (and most other small, soft-bodied organisms) lack a useful fossil record for this purpose. As a result, employing “universal” rates of molecular evolution to estimate divergence times is common, even though evolutionary rates can vary considerable across taxa. In Chapter 3, I assess the validity of the generalized arthropod rate assumption by conducting a Bayesian phylogenetic analysis to evaluate the relative rate of molecular evolution across all major hexapod groups. I found that substitution rates in Collembola are not significantly different from most other hexapod groups and suggest that the use of “universal” insect molecular clocks are appropriate for estimating collembolan evolutionary timescales. An additional yet fundamental challenge impacting all fields of biology is the fact that most biodiversity remains to be discovered or is poorly understood—including many species that are of potential conservation concern. This is exacerbated in collembolan taxonomy, due to the lack of variation in discrete morphological characters, and the general shortage of taxonomic expertise in North America, reflected in the limited number of taxonomic tools available to researchers (and the public) for identifying species in this region. To help address this challenge, I produced detailed morphological taxonomic descriptions for all New World species of the springtail genus Willowsia, including a new species that is endemic to Florida in Chapter 4. Most members in this genus are from Asia, but comparative morphological analysis revealed two unique character states shared only by endemic New World Willowsia and Americabrya, providing prima facie evidence of their independent evolution from a common New World ancestor.
... Symphypleona have so far only been caught in air (up to 3350 m, [18,50]) and, as strictly terrestrial and freshwater inhabitants, there is no evidence that they could maintain themselves in association with brackish water [51]. However, Symphypleona, which extends into Spanish amber dated to the Lower Cretaceous [52], display many recently diverged clades (e.g. genera Sminthurinus and Sminthurides) on every continent. ...
... Three of the four orders of modern springtails are reported from termite and ant nests [55,[65][66][67]. This includes cyphoderids primarily described as nests inquilines as well as direct commensals of termites and ants [52][53][54][55][56]67]. Thus, despite constraints in collecting modern phoretic springtails, other reported cases suggest significant relationships with social insects. ...
Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods.
Results: Here, we document the case of a ~ 16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the
general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today.
Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today
... A new species of this group from a cave in the southwestern U.S. contains a selection of these characters and necessitates a review of the status of these genera. The objectives of this paper are to describe Disparrhopalites naasaveqw n. sp.; synonymise DietersminthurusPalacios-Vargas, Cuéllar & Vázquez, 1998with Disparrhopalites Stach, 1956; transfer several sminthurid genera to Songhaicinae SánchezGarcía & Engel, 2016; and provide a key to this distinctive group of small-sized Sminthuridae. ...
... Songhaica was considered byBretfeld (1999)to be intermediate in position between Sphyrothecinae and Sminthurinae, but primarily allied with Sminthurinae. SánchezGarcía & Engel (2016)established Songhaicinae with a very brief diagnosis and without direct comparison to the other subfamilies. Sphyrothecinae and Songhaicinae are similar in usually having fewer than 20 subsegments in Abd. ...
Disparrhopalites naasaveqw n. sp. is described from a cave at Wupatki National Monument, Arizona. It differs from D. patrizii (Cassagnau & Delamare Deboutteville, 1953) in having pigment and a well-developed ungual cavity, and from D. tergestinus Fanciulli, Colla & Dallai, 2005 by having pigment, 8+8 eyes and a well-developed ungual tunica. Dietersminthurus enkerlinius Palacios-Vargas, Cuéllar & Vázquez, 1998 is transferred to Disparrhopalites Stach, 1956 as D. enkerlinius (Palacios-Vargas, Cuéllar & Vázquez, 1998) n. comb. The sminthurid subfamily Songhaicinae Sánchez-García & Engel, 2016 (type genus Songhaica Lasebikan, Betsch & Dallai, 1980) is redefined and the genera Disparrhopalites, Gisinurus Dallai, 1970, Soqotrasminthurus Bretfeld, 2005 and Varelasminthurus Da Silva, Palacios-Vargas & Bellini, 2015 are transferred to this subfamily. A key is provided for separation of included genera. Effects of climate change on presumed cases of cave restriction in the American Southwest are discussed.
... The present revision considers the fauna of Entomobryomorphan springtails preserved in Early Cretaceous amber from Spain, complementing the earlier overview of Collembola from these deposits by SimónBenito et al. (2002). Preparation, photography, and imaging of the amber and its inclusions followed the procedures outlined by SánchezGarcía and Engel (2016), which started with initial screening of pieces for biotic inclusions followed by vacuumembedding in a stable epoxy resin (Epotek 301) (Nascimbene and Silverstein, 2000). The embedded amber was then suitable for trimming, grinding, and polishing using a waterfed flat lap. ...
... Line drawings were prepared with the aid of a camera lucida attached to the Olympus BX41 compound microscope at the University of Kansas. For the systematic work, the higher classifications of Folsom (1937a), Potapov (2001), and SotoAdames et al. (2008, are followed, and morphological terminology for the descriptions is generally based on Potapov (2001), Fjellberg (2007), and as modified by SánchezGarcía and Engel (2016), with descriptions provided in the context of expanding upon evolutionary patterns (e.g., Grimaldi and Engel, 2007). All material is deposited in the Museo de Ciencias Naturales de Álava, VitoriaGasteiz, Álava, Spain, abbreviated as MCNA herein. ...
Entomobryomorphan springtails (Hexapoda: Entognatha: Collembola) of the family Isotomidae are the most numerous group of Collembola in Spanish amber, a pattern typical in other studied Cretaceous amber deposits. Here we provide a revision of the Spanish amber springtail fauna, Early Cretaceous (Late Albian) in age, based on 93 specimens sufficiently well preserved to permit specific identification. Three new species are erected within the Isotomidae: Anurophorinae. These are: Burmisotoma spinulifera, new species, Protoisotoma autrigoniensis, new species, and Proisotoma communis, new species. The two former are respectively placed in the Cretaceous genera Burmisotoma Christiansen and Nascimbene (previously known from Cenomanian Burmese amber) and Protoisotoma Christiansen and Pike (in both Burmese and Canadian ambers), while the last species is indistinguishable from the extant, cosmopolitan genus Proisotoma Börner (also recorded in Burmese amber). Low morphological intraspecific variability is described for P. communis. Taxa are discussed in relation to other fossil entomobryomorphan lineages as well as their modern counterparts. A catalog of the known fossil springtails is appended. Isotomidae are diverse springtails, putatively basal among Entomobryomorpha and extending back into the Early Devonian. Indeed, taxa described herein are overall remarkably similar to their extant relatives, emphasizing the antiquity and morphological stasis of the group as a whole.
... Spiders are extremely sensitive to natural and man-made disturbances (Pearce and Venier, 2006). Similarly, the Symphypleona collembola group is very prone to decrease with changes in habitat or climate, and therefore is expected to be more affected by changes in land use than other groups (Engel et al., 2015;Sánchez-García et al., 2016;Sánchez-García and Engel, 2017). The Blattodea and Thysanoptera groups seek shelter in bark, litter, anthills, termite mounds and hot and humid places (Baretta et al., 2011), constituting conditions which are more easily found in native forests. ...
Soil mesofauna plays an important role in soil aggregation, which conditions the physical protection of soil organic carbon (SOC). Thus, our study associates the evaluation of mesofauna and SOC quantification to generate relevant information on the influencing level of these organisms on organic matter dynamics in aggregates. It is even more important investigating these indicators in places where decomposition processes are more intense, such as forest systems under tropical soils, where little is known about the interaction between these variables. In this context, the present study aimed to evaluate: (1) the influence of homogeneous Pterogyne nitens and Pinus caribaea plantations on the edaphic mesofauna community and on SOC stocks and carbon in soil aggregate classes using a native forest as a reference; and (2) the interaction between edaphic mesofauna, SOC and aggregate carbon. This study was performed on Oxisol soil areas located in the municipality of Vitória da Conquista, Bahia, Brazil. The edaphic mesofauna was evaluated using the modified Berlese-Tullgren funnel method. Physical soil fractionation was carried out by wet sieving. The organic carbon contents of the soil and aggregates were determined by wet oxidation. Implantation of homogeneous Pterogyne nitens and Pinus caribaea stands causes a reduction in the edaphic mesofauna (abundance and average richness) and in the amount of soil macroaggregates. The differences between the forest systems are largely explained by the abundance of fauna, SOC and carbon of the macroaggregates, microaggregates and silt + clay. The edaphic mesofauna has a direct and positive influence on the SOC, which highlights its important role in regulating the soil carbon dynamics in the soil.
... The family Sminthuridae Lubbock, 1862 [1] has about 260 nominal species in 32 genera and represents one of the most common and widespread groups of Symphypleona [2][3][4]. It comprises three subfamilies of which the Sminthurinae, Lubbock, 1862 is the largest, with about 180 species described in 12 extant and seven extinct genera [2,[4][5][6][7][8][9]. The diagnosis of Sminthurinae was recently updated by Zeppelini et al. [9] and its main features are long antennae, mostly longer than the body; fourth antennal segment with well-marked subsegments; tibiotarsi with more than six chaetae on distal whorl; ungues without cavity; absence of neosminthuroid chaetae on the parafurcal area except in Keratosminthurus Zeppelini, 2020 in Zeppelini et al. 2020 [9]; dens ventrally usually with more than 9 chaetae [2,5,9]. ...
Richardsitas Betsch is a small genus of Sminthurinae with only two species described so far, both from Madagascar. It resembles other Sminthurinae with long antennae, especially Temeritas Richards. Here we provide the first record of Richardsitas from Australia, Richardsitas subferoleum sp. nov., which is similar to R. najtae Betsch and R. griveaudi Betsch in males’ large abdomen chaetotaxy and presence of tenent-hairs on tibiotarsi II–III, but lacks mucronal chaeta and has 28 segments on the fourth antennal segment plus a unique pair of sensilla on the second. We also provide an updated genus diagnosis to Richardsitas, a key to its species, a discussion of the affinities of Temeritas and Richardsitas to other Sminthurinae, and an updated key to this subfamily.
... Symphypleona have so far only been caught in air (up to 3350 m, [18,43]) and, as strictly terrestrial and freshwater inhabitants, there is no evidence that they could maintain themselves in association with brackish water [44]. However, Symphypleona, which extends into Spanish amber dated to the Lower Cretaceous [45], display many recently diverged clades (e.g. genera Sminthurinus and Sminthurides) on every continent. ...
Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with dipluran), are reported since the Lower Devonian and thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent, implying an ability to disperse over oceans although never reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are generally rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results: Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or closely connected to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviors. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails and the drastic increase of eusocial insects’ abundance over Cenozoic (ants/termites comprising more than the third of insects in Miocene amber), we stress that attachment with winged casts of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behavior continues today. Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the actual dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today. Associations with soil-dwelling social insects over time would have been at the origin of this behavioural specialization.
... Symphypleona have so far only been caught in air (up to 3350 m, [18,43]) and, as strictly terrestrial and freshwater inhabitants, there is no evidence that they could maintain themselves in association with brackish water [44]. However, Symphypleona, which extends into Spanish amber dated to the Lower Cretaceous [45], display many recently diverged clades (e.g. genera Sminthurinus and Sminthurides) on every continent. ...
Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results: Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today. Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today.
... Symphypleona have so far only been caught in air (up to 3350 m, [18,43]) and, as strictly terrestrial and freshwater inhabitants, there is no evidence that they could maintain themselves in association with brackish water [44]. However, Symphypleona, which extends into Spanish amber dated to the Lower Cretaceous [45], display many recently diverged clades (e.g. genera Sminthurinus and Sminthurides) on every continent. ...
Background: Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with Diplura), are reported since the Lower Devonian and are thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent. This distribution implies an ability to disperse over oceans, however symphypleonan Collembola have never been reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Results: Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or in close proximity to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviours. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails, and the drastic increase of eusocial insects’ abundance during the Cenozoic (ants/termites comprising more than a third of insects in Miocene amber), we stress that attachment on winged castes of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behaviour continues today. Conclusions: The specific case of tree resin entrapment represents the (so far) only condition uncovering the phoretic dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today.
... 400 Ma ago (Scourfield, 1940;Greenslade and Whalley, 1986), and present in terrestrial environments as diverse, modern species assemblages as soon as the Early Cretaceous, ca. 110 Ma ago (Sánchez-García and Engel, 2017;Sánchez-García et al., 2018). Palaeozoic families have seemingly crossed the Cretaceous-Paleogene (K-Pg) mass extinction, which devastated the global environment and destroyed three quarters of plant and animal species on Earth ca. ...
The present opinion paper suggests that springtails, which can live above- and/or belowground according to species requirements, have two strategies at their disposal to face environmental hazards, called ‘move’ or ‘change’. Species with poor dispersal capacity, often parthenogenetic, and living mainly in a confined environment, have to adapt themselves by increasing their phenotypic plasticity or letting the environment selecting or adding favourable mutations. Conversely, species with a high dispersal capacity, often sexual and living in a more open environment, may emigrate and immigrate without the need to become better adapted to changing environmental conditions. Advantages and disadvantages of these two tactics are reviewed and their prospective responses to global changes are compared on the light of existing knowledge on this microarthropod group.
... nov. (see Betsch 1980Betsch , 1997Bretfeld 1999;Sánchez-García & Engel 2016;Bernard & Wynne 2017). The posterior cephalic chaetotaxy of the new genus is a point for discussion, Keratosminthurus gen. ...
A new genus and two new species of Sminthurinae are described. Keratosminthurus tapigu gen. nov. sp. nov. and K. calamitosus sp. nov. show a combination of features that redefines the subfamily Sminthurinae, such as a pair of sminthuroid chaetae, unguis without cavity, nine apical chaetae on tibiotarsus, 11 or more anterior dental chaetae, fourth antennal segment clearly subdivided into many (18 or more) subsegments, and asymmetric apex of mucro. The new genus also presents a striking sexual dimorphism, with modifications on male apical organ of antennal segment III, spines on the clypeus and special organs on the interocular area.
... Symphypleona have so far only been caught in air (up to 3350 m, [18,43]) and, as strictly terrestrial and freshwater inhabitants, there is no evidence that they could maintain themselves in association with brackish water [44]. However, Symphypleona, which extends into Spanish amber dated to the Lower Cretaceous [45], display many recently diverged clades (e.g. genera Sminthurinus and Sminthurides) on every continent. ...
Dispersal is essential for terrestrial organisms living in disjunct habitats and constitutes a significant challenge for the evolution of wingless taxa. Springtails (Collembola), the sister-group of all insects (with dipluran), are reported since the Lower Devonian and thought to have originally been subterranean. The order Symphypleona is reported since the early Cretaceous with genera distributed on every continent, implying an ability to disperse over oceans although never reported in marine water contrary to other springtail orders. Despite being highly widespread, modern springtails are generally rarely reported in any kind of biotic association. Interestingly, the fossil record has provided occasional occurrences of Symphypleona attached by the antennae onto the bodies of larger arthropods. Here, we document the case of a ~16 Ma old fossil association: a winged termite and ant displaying not some, but 25 springtails attached or closely connected to the body. The collembola exhibit rare features for fossils, reflecting their courtship and phoretic behaviors. By observing the modes of attachment of springtails on different arthropods, the sex representation and ratios in springtail antennal anatomies in new and previously reported cases, we infer a likely mechanism for dispersal in Symphypleona. By revealing hidden evidence of modern springtail associations with other invertebrates such as ants and termites, new compelling assemblages of fossil springtails and the drastic increase of eusocial insects' abundance over Cenozoic (ants/termites comprising more than the third of insects in Miocene amber), we stress that attachment with winged casts of ants and termites may have been a mechanism for the worldwide dispersal of this significant springtail lineage. Moreover, by comparing the general constraints applying to the other wingless soil-dwelling arthropods known to disperse through phoresy, we suggest biases in the collection and observation of phoretic Symphypleona related to their reflexive detachment and infer that this behavior continues today. The specific case of tree resin entrapment represents the (so far) only condition uncovering the actual dispersal mechanism of springtails - one of the oldest terrestrial arthropod lineages living today. Associations with soil-dwelling social insects over time would have been at the origin of this behavioural specialization.
... However, the preferred habitat of the Spanish fossil mesoveliids might also be characterized as marginal aquatic and therefore transitional between terrestrial and freshwater environments (Fig. 11). Indeed, the rest of the arthropod assemblage is consistent with such an environment, with numerous representatives of the ground habitat of humid forests preserved in 'litter amber' (Sánchez-García et al., 2015;Sánchez-García, Arillo & Nel, 2016;Arillo, Subías & Sánchez-García, 2016;Sánchez-García & Engel, 2016a;Sánchez-García & Engel, 2016b). ...
Pondweed bugs (Hemiptera: Mesoveliidae), considered a sister group to all other Gerromorpha, are exceedingly rare as fossils. Therefore, each new discovery of a fossil mesoveliid is of high interest, giving new insight into their early evolutionary history and diversity and enabling the testing of their proposed relationships. Here, we report the discovery of new mesoveliid material from Spanish Lower Cretaceous (Albian) amber, which is the first such find in Spanish amber. To date, fossil records of this family only include one species from French Kimmeridgian as compression fossils, two species in French amber (Albian-Cenomanian boundary), and one in Dominican amber (Miocene). The discovery of two males and one female described and figured as Glaesivelia pulcherrima Sánchez-García & Solórzano Kraemer gen. et sp. n., and a single female described and figured as Iberovelia quisquilia Sánchez-García & Nel, gen. et sp. n., reveals novel combinations of traits related to some genera currently in the subfamily Mesoveliinae. Brief comments about challenges facing the study of fossil mesoveliids are provided, showing the necessity for a revision of the existing phylogenetic hypotheses. Some of the specimens were studied using infrared microscopy, a promising alternative to the systematic study of organisms preserved in amber that cannot be clearly visualised. The new taxa significantly expand the fossil record of the family and shed new light on its palaeoecology. The fossils indicate that Mesoveliidae were certainly diverse by the Cretaceous and that numerous tiny cryptic species living in humid terrestrial to marginal aquatic habitats remain to be discovered. Furthermore, the finding of several specimens as syninclusions suggests aggregative behaviour, thereby representing the earliest documented evidence of such ethology.
... In this respect, the marsupium represents a safe environment for the offspring and has certainly contributed to the success of Tanaidacea (as well as amphipods and isopods) in diverse habitats, including marine, freshwater, and even moist-terrestrial environments, as has been proposed for some tanaidaceans found in Cretaceous ambers 18,19 . French and Spanish amber deposits largely represent a sampling of taxa from above the forest floor but also from the soil and litter and even nearby aquatic habitats [60][61][62] . In fact, there are various other arthropods together preserved with the tanaidaceans that are indicators of a litter-dwelling to semi-aquatic fauna 18,19 . ...
Parental care in animal evolution has long fascinated biologists, but tracing this complex of behavioural repertoires is challenging, as these transitory states often leave no corporeal traces as fossils. Among modern invertebrates, the tanaidaceans (Malacostraca: Peracarida), a lineage of marsupial crustaceans, show an interesting variety of brooding strategies. Here we report on fossil tanaidaceans from the Cretaceous of Spain and France that provide conclusive evidence for marsupial care of brood-offspring. Two exceptionally preserved female specimens of Alavatanais carabe and A. margulisae from Late Albian Peñacerrada I amber (Spain) possess four pairs of rudimentary oostegites, indicating formation of a marsupium. From Recent data, given the taxonomic distribution of a marsupium of four pairs of oostegites, we hypothesize that this may be plesiomorphic for the Tanaidomorpha. We also report on a peculiar tanaidacean specimen referable to the fossil family Alavatanaidae, Daenerytanais maieuticus gen. et sp. nov., from Early Cenomanian La Buzinie amber (France), preserved with its marsupial pouch and content. Our discoveries provide early evidence of the peracarid reproductive strategy, as seen in modern Tanaidacea, and argue that this form of parental care may have played a role in the diversification of the lineage during this period.
... Given their small sizes and soft bodies, the fossil record of Collembola is rather sparse, with only one other occurrence from the Paleozoic 13 . However, by the Cretaceous and the prevalence of amber deposits, ideally suited for the preservation of such minute arthropods, there is a diverse and rich record of springtails (summarized by Sánchez-García and Engel) 14 , and in some localities and pieces they can be numerous [15][16][17][18][19] . Burmese amber harbors one of the most diverse faunas of Collembola, represented by 14 described species in 13 genera 16 . ...
Insects exhibit a variety of morphological specializations specific to particular behaviors, and these permit the reconstruction of palaeobiological traits. Despite the critical importance of predator-prey strategies in insect evolution, the appearance of particular aspects of predation are often difficult to determine from the fossil record of hexapods. Here we report the discovery of highly specialized, mid-Cretaceous ant-like stone beetles (Staphylinidae: Scydmaeninae) displaying morphological modifications unknown among living scydmaenids and associated with predation on springtails (Collembola), a widespread and abundant group of significantly greater geological age. Cascomastigus monstrabilis gen. et sp. nov. exhibits an extremely large body size, elongate clubbed maxillary palpi, toothed mandibles, and more importantly, slender and highly modified antennae that functioned as an antennal setal trap. Such an antennal modification is analogous to that of the modern ground beetle genus Loricera (Carabidae: Loricerinae), a group possessing a specialized antennal setal trap exclusively for the capture of springtails. The presence of an identical antennal setal trap in C. monstrabilis demonstrates a unique and dramatic form of obligate predation among the late Mesozoic insects.
Temperature is a primary driver to define the ecophysiological activity and performance of ectotherms. Thus, thermal tolerance limits have a profound effect in determining geographic ranges. In regions with extreme cold temperatures, lower thermal limits of species are a key physiological trait for survival. Moreover, thermal niche breadth also plays an important role in allowing organisms to withstand climatic variability and confers species with broader potential to establish in new regions. Here we study the evolution of thermal tolerance limits among Collembola (Arthropoda) and explore how they are affected by the colonization of polar environments. In addition, we test the hypothesis that globally invasive species are more eurythermal than non‐invasive ones. Critical thermal limits (CTmin and CTmax), classic measurements of thermal tolerance, were compiled from the literature and complemented with experimental assays for springtail species. Genetic data of the mitochondrial gene cytochrome oxidase subunit 1 (COI) was used to assemble a phylogeny. Our results show that polar springtails have lower CTmin and lower CTmax compared to species from temperate and tropical regions, consistent with the Polar pressure hypothesis. We found no phylogenetic signal for CTmax, but low values of phylogenetic signal for CTmin. Globally invasive species do not have significantly broader thermal tolerance breadth (CTrange) than non‐invasive ones, thus not supporting the predictions of the Eurythermality hypothesis. We conclude that polar springtails have evolved their thermal niches in order to adapt to extremely cold environments, which has led to decreasing both upper and lower thermal tolerance limits.
Diplura are an ancient group of basal (apterygote) hexapods that thrive in various cryptic terrestrial habitats. Despite an ancient origin that extends at least to the Devonian period, the dipluran fossil record is exceedingly sparse. Here, we document five very rare fossil specimens of the family Campodeidae in amber from the Miocene of the Dominican Republic and the Eocene of the Baltic region. Microscopic preservation in amber provides unique detail for taxonomic placement of small, delicate, soil- and leaf litter-dwelling organisms like these. New taxa include the following: in Lepidocampinae, Lepidocampa glaesi sp. nov. (in Dominican amber); and in Campodeinae, Litocampa eobaltica sp. nov. (in Baltic amber) and Rostricampa engeli gen. et sp. nov. (in Dominican amber). Rostricampa has an extraordinary rostrum formed by sclerotized extensions of the clypeus and, probably, the labium, unique among diplurans. These new taxa provide rare additional data on the fossil record of the earliest diverging lineages of the hexapods and shed light on their evolution and ecology.
Two new species of Sminthurididae, Sphaeridia piauiensis Medeiros & Bellini, sp. nov. and Denisiella piracurucaensis Silva, Medeiros & Bellini, sp. nov. from Piaui state, Brazil, are herein described and illustrated. Sphaeridia piauiensis sp. nov. resembles species of the irmleri group, like S. irmleri Bretfeld & Gauer, S. fibulifera Bretfeld & Gauer, and S. peruensis Bretfeld & Schulz, by its complex male ventral tube without asymmetrical structures or medial process. However, it differs from them by the combination of the male tibiotarsus III with a leaf-shaped IIpe chaeta and a regular IIIpi chaeta, ventral tube with 1+1 chaetae, and the absence cuticular hooks on the furca. Denisiella piracurucaensis sp. nov. resembles its congeners without the nasal organ, especially D. colombiana Ospina & Palacios-Vargas, by the presence of spiniform chaetae at least on the second antennal segment of the females, four serrated spines on tibiotarsus III, and the ventral dens chaetotaxy, but D. piracurucaensis sp. nov. differs from the latter especially by the presence of 8+8 eyes and the shape of the male proximal tibiotarsal organ. To describe both species all Neotropical Sphaeridia and all described Denisiella species were surveyed, presenting notes on both genera, comparative tables, and keys for these taxa.
Simple Summary
A new genus and species of cave springtail are herein described. The new species has a remarkable morphology, suggesting it evolved within caves, such as the appendages and chaetae elongation, loss of body pigments, and 5 + 5 eyes reduced in size. The new species may also be occasionally cannibalistic, as one of the analyzed females devoured another male from her species.
Abstract
Here, we describe the highly troglomorphic Troglobentosminthurus gen. nov. from Água Clara cave system, Caatinga domain, Bahia, Brazil. Troglobentosminthurus luridus gen. nov. sp. nov. has remarkably long antennae, legs and furca, and lacks body pigments, except for small orange eye patches which also show a reduction in the number of eyes (5 + 5) and lens sizes. The overall morphology of the genus, with long and highly sub-segmented antennae, resembles other Sminthurinae of the Temeritas-group, especially Temeritas Richards and Galeriella Ćurčić and Lučić. However, it is unique, especially in the combination of the number of antennae IV subsegments and eyes, frontal head chaetotaxy and empodial complex morphology. Two type specimens have remnants of a mite and another specimen from the new species in their gut contents, supporting the species may be occasional predators and even cannibals. We also provide identification keys and comparative tables to the subfamilies of Sminthuridae and the Temeritas-group of genera.
Barklice are insects belonging to the order Psocodea. They are herbivorous or detritivorous, and inhabit a wide range of environments. Their oldest fossil record dates back to the late Carboniferous, but it was not until the Cretaceous that they became much more diverse. However, their fossil record could be affected by taphonomic processes due to their tiny size and soft bodies. Here, we present new psocid specimens from five amber‐bearing outcrops in Spain that are Albian in age. One of the specimens, a well‐preserved psocid nymph assigned to †Archaeatropidae, lacks evidence of debris‐carrying behaviour. Some of the specimens belong to the previously known species Archaeatropos alavensis Baz & Ortuño and Preempheria antiqua Baz & Ortuño (Trogiomorpha: Atropetae), providing new anatomical and biogeographical information. Furthermore, we describe a new species, Libanoglaris hespericus sp. nov. (†Archaeatropidae). The diagnosis for the family †Archaeatropidae is emended. The abundance of psocids in Cretaceous amber and their virtual absence in compression outcrops could be due to taphonomic bias. Considerations on the phylogenetic placement of trogiomorphan families and the relationships between †Archaeatropidae and †Empheriidae are included. Today, the least diverse psocid suborder is Trogiomorpha, but this suborder comprises the majority of the Cretaceous psocodean species described to date, possibly due to palaeobiological or evolutionary constraints. Trogiomorphans could have been relegated to marginal habitats by niche competition with psocomorphans. Debris‐carrying behaviour in response to predatory pressure might not have been widely distributed, geographically or phylogenetically, in the Cretaceous psocid nymphs.
Terrestrial isopods (Crustacea: Oniscidea) are a model group for studying the colonization of land. However, their fossil record is remarkably scarce and restricted to amber inclusions, and therefore amber deposits represent valuable windows to their past diversity and morphology. Here we present a new collection of 11 terrestrial isopod specimens preserved in Albian-aged amber from the Peñacerrada I outcrop, northern Spain, which collectively represent the most thoroughly documented fauna of Mesozoic Oniscidea. The three new genera and species identified belong to three of five major groups of the Oniscidea: Eoligiiscus tarraconensis, new genus and species (Ligiidae), Autrigoniscus resinicola, new genus and species (Synocheta: Trichoniscidae), and Heraclitus helenae, new genus and species (Crinocheta: Detonidae?). These taxa significantly expand the known fossil record of Oniscidea and demonstrate that considerable cladogenesis had already transpired by the Albian. The assemblage represents the earliest-known diversification of Oniscidea, extending direct evidence of terrestrialization in the group back to the late Early Cretaceous. These new taxa exhibit some characteristics that may inform hypotheses relating to general patterns of terrestrial isopod evolution. A discussion is provided about different aspects of the paleoecology and biology of the fossils compared to the Recent fauna. The new species indicate that Cretaceous isopods were a group of considerable adaptive diversity, exhibiting innovations analogous to what Recent isopods would exhibit 105 million years later.
Two virtually complete termites in Lower Cretaceous amber from the Peñacerrada I outcrop, Spain, are described and figured, representing the most well-preserved Isoptera yet discovered from the Albian stage. The material is described as Ithytermes montoyai gen. et sp. nov., and is similar in many details to the slightly younger Krishnatermes yoddha Engel, Barden, and Grimaldi from northern Myanmar amber. Given the presence of distinct soldiers in this grade of Cretaceous termites, it is likely that I. montoyai also exhibited such a tripartite caste system. In addition to the type material of I. montoyai, two fragmentary termites are recorded for the first time in Albian amber from the El Soplao outcrop, and in the few preserved details these taxa are not conspecific with the former.
Non-biting midges (Chironomidae) have a fossil record reaching back into the Triassic. The non-biting midge ingroup Libanochlites Brundin, 1976, was so far known from a single species. Fossil specimens of this species came from the Cretaceous of Gondwana, more precisely from Lebanese amber (130 million years). A new species, based on fossils in Eocene Baltic amber, is so similar to the so far single species of Libanochlites that it can only be attributed to this group. This is extending the known geological range of this so far unique morphology by 80 million years. This provides us with the first case of the long-term survival (“Bradytely”) of a distinct Mesozoic morphotype of a representative Diptera with aquatic larvae into the Cenozoic. Bradytely is a phenomenon describing evolutionary stasis. This represents a case of bradytely in insects with aquatic larvae and has an impact on our understanding of the Cretaceous terrestrial revolution. Primarily, this record allows us to determine conditions which are permitting the survival of the Mesozoic aquatic insects into the Palaeogene. The conditions are related to the bradytely of the insects with aquatic larvae in the temperate, subtropical forest.
Jumping bristletails (order Archaeognatha), the basalmost order of extant insects, include some of the earliest fossil records among hexapods, yet their overall geological occurrence remains sparse and has provided little insight into their evolution. The earliest representatives of crown‐group bristletails are those in Lebanese amber (Cretaceous), hitherto known only from a single species. Here we significantly expand the known fossil record of Archaeognatha, and from the prolific Lower Cretaceous (Barremian) deposits of Lebanon. One new genus and species, Glaesimeinertellus intermedius gen. et sp. nov., and one new species, Macropsontus bachae sp. nov., are described and figured from Hammana amber, whereas one additional Macropsontus species, M. azari sp. nov., and one meinertellid morphotype are described and figured from Al‐Rihan amber. The new taxa are compared with their modern and fossil relatives. Collectively, the new taxa render the Archaeognatha fauna from Lebanese amber the earliest with sufficient preservation to provide character data comparable to modern forms, highlighting the considerable morphological conservatism within the order.
A new diagnosis of Denisiella is provided, based on the revision of most descriptions, including three new species from Brazil. New Brazilian taxa share the presence of 6 + 6 eyes, 4 + 4 serrate spine-like on tibiotarsi III and the polycarinate setae on tibiotarsi II but differ from each other by the shape and size of the sensilla of the tibiotarsi I. Denisiella rhizophorae sp. nov. has the combination of sensilla on tibiotarsi I of rhagidial type and C2 blunt on antennal segment III. Only D. betschi sp. nov. has barbulate spines on head and D. caatingae sp. nov. is the only which males present nasal organ. They are illustrated with drawings and scanning electron microscope photographs. Three different shapes of sensilla in the tibiotarsi I were observed and were compared with other species.
All the amber outcrops of the Iberian Peninsula are Lower Cretaceous in age and, in the case of Spain, some of them have provided important arthropod specimens preserved as bioinclusions. These Spanish localities are rich in fossil taxa of phylogenetic relevance and evidence of both paleoecological interactions and paleobehaviors are also abundant. Despite their high heritage interest, the actions conducted to their protection and management have been very unequal. In some cases, only the generic laws of national or autonomous scopes protect this heritage. In this paper, the state of the art of the Iberian Peninsula amber outcrops and a review of the major Cretaceous amber outcrops worldwide for comparison are presented. That comparison shows, in general, that the best protection, both legal and physical, occurs in Spain and that the case of Portugal is very different. In addition, some actions aimed at a more effective protection and management of the amber outcrops in Spain and Portugal are proposed, for example the proposal to consider the San Just outcrop, located in the Aragonese Community, under a protection designation as is the so called Bien de Interés Cultural.
Entomobryomorphan springtails (Hexapoda: Entognatha: Collembola) of the family Isotomidae are the most numerous group of Collembola in Spanish amber, a pattern typical in other studied Cretaceous amber deposits. Here we provide a revision of the Spanish amber springtail fauna, Early Cretaceous (Late Albian) in age, based on 93 specimens sufficiently well preserved to permit specific identification. Three new species are erected within the Isotomidae: Anurophorinae. These are: Burmisotoma spinulifera, new species, Protoisotoma autrigoniensis, new species, and Proisotoma communis, new species. The two former are respectively placed in the Cretaceous genera Burmisotoma Christiansen and Nascimbene (previously known from Cenomanian Burmese amber) and Protoisotoma Christiansen and Pike (in both Burmese and Canadian ambers), while the last species is indistinguishable from the extant, cosmopolitan genus Proisotoma Börner (also recorded in Burmese amber). Low morphological intraspecific variability is described for P. communis. Taxa are discussed in relation to other fossil entomobryomorphan lineages as well as their modern counterparts. A catalog of the known fossil springtails is appended. Isotomidae are diverse springtails, putatively basal among Entomobryomorpha and extending back into the Early Devonian. Indeed, taxa described herein are overall remarkably similar to their extant relatives, emphasizing the antiquity and morphological stasis of the group as a whole.
A fossil palpigrade is described and figured from mid-Cretaceous (Cenomanian) amber from northern Myanmar. Electrokoenenia yaksha Engel and Huang, gen. n. et sp. n., is the first Mesozoic fossil of its order and the only one known as an inclusion in amber, the only other fossil being a series of individuals encased in Pliocene onyx marble and 94–97 million years younger than E. yaksha. The genus is distinguished from other members of the order but is remarkably consistent in observable morphological details when compared to extant relatives, likely reflecting a consistent microhabitat and biological preferences over the last 100 million years.
The intense study of coleopteran inclusions from Spanish (Albian in age) and French (Albian–Santonian in age) Cretaceous ambers, both of Laurasian origin, has revealed that the majority of samples belong to the Polyphaga suborder and, in contrast to the case of the compression fossils, only one family of Archostemata, one of Adephaga, and no Myxophaga suborders are represented. A total of 30 families from Spain and 16 families from France have been identified (with almost twice bioinclusions identified in Spain than in France); 13 of these families have their most ancient representatives within these ambers. A similar study had previously only been performed on Lebanese ambers (Barremian in age and Gondwanan in origin), recording 36 coleopteran families. Few lists of taxa were available for Myanmar (Burmese) amber (early Cenomanian in age and Laurasian in origin). Coleopteran families found in Cretaceous ambers share with their modern relatives mainly saproxylic and detritivorous habits in the larval or adult stages, rather than wood-boring behavior. Fifteen of the coleopteran families occur in both the Lebanese and Spanish ambers; while only five are present in both Spanish and French. Considering the paleogeographic proximity and similarity of age of the Spanish and French ambers, the small number of taxa found in common at both areas is surprising. The ancient origin for the Lebanese and Spanish ambers, the paleogeography (including some barriers for terrestrial biota) and the local paleohabitats are factors that may explain the dissimilarity with the French specimens. Wildfires are believed to be a more likely cause of resin production during the Cretaceous than infestation by beetles. Current knowledge of the beetle species found in the Cretaceous ambers is introduced.
Two new Mexican Sminthurids (Collembola: Symphypleona) from humid tropical forests from Quitana Roo are described.
A series of experiments were conducted to determine the impact of Protaphorura fimata Gisin (Family: Onychiuridae) feeding on seeds and germinating seedlings of lettuce, Lactuca sativa L. (Asteraceae). First, various densities of P. fimata were incubated with 25 lettuce seeds for 7 d and feeding injury was evaluated in three soilless arena experiments. As a second step, 100 P. fimata were incubated with 25 lettuce seeds in three arena experiments with soil media. Finally, in a commercial field the incidence and impact of P. fimata on recently planted lettuce was assessed following applications of pyre-throid–insecticides: 2 d before planting, at planting, and 20 d later. In experiments without soil, the num-ber of ungerminated seeds, feeding injury sites, and plants with injury were significantly greater in arenas with P. fimata than without. Similarly, the number of germinated seedlings, shoot fresh, and dry weights, and the length and width of fully opened-leaves were greater in arenas without than with P. fimata in as-says with soil. In the field, P. fimata densities were significantly lower in beds that received insecticides at 2 d before and at planting than in untreated beds. Also, the fresh and dry weights of lettuce plants were significantly greater in the beds that received insecticide than in untreated. The results clearly show that P. fimata is a pest of lettuce and can cause severe feeding injury to germinating seeds or seedlings, thereby reducing their growth rate. The potential implications of P. fimata feeding and feeding injury characteristics are discussed.
The Lower Cretaceous deposits of the southern margin of the Basque-Cantabrian basin (northern Spain) are characterised by continental deposits interbedded with amber-bearing marine-influenced facies. These facies crop out in various localities and have yielded well-preserved palynological assemblages. The palynoflora is dominated by gymnosperm pollen grains, and shows relatively diversified spore content but scarce dinoflagellate cysts. The palynofloral evidence and regional geological setting indicate that the studied successions are dated as Aptian (Montoria-La Mina outcrop) and late Albian (Peñacerrada 1 and 2 and Salinillas de Buradón outcrops, and the Pancorbo site). Angiosperm pollen does not constitute a significant part of the Aptian assemblages but becomes diversified and numerically abundant in those dated as late Albian. Although broadly similar to contemporaneous palynofloras from eastern Spain, the Aptian assemblages of Montoria-La Mina do not yield tricolpate angiosperm pollen. Conversely, the inferred late Albian assemblages show a high content in polyaperturate angiosperm pollen grains, as occurs in other localities in Portugal, Western Europe and North America. The studied palynoflora shows significant differences from published assemblages located further north, in western France and Canada.
Platygastroid wasp diversity in Álava amber is reviewed. Platygastroids are the most numerous group of Hymenoptera in Spanish amber, a pattern typical for many Cretaceous amber deposits, with species of the superfamily sometimes more abundant than all other arthropod lineages. Herein we report on 87 specimens, 62 of them sufficiently preserved to permit specific identification, and all dating from the Lower Cretaceous (middle Albian). Eight new gen-era and nine new species are described and figured as Proterosceliopsis gen. nov., Proterosceliopsis masneri sp. nov., sp. nov. Morphological interspecific variability is low, hindering identification, and as such, taxa are principally diagnosed on structure of the female an-tenna, tibial spur formula, mesoscutal form, and head and metasomal anatomy. The taxa are discussed in relation to other fossil lineages of platygastroids as well as modern counterparts. All species belong to the "Scelionidae", a paraphyletic group relative to Platygastridae as currently circumscribed (including Platygastrinae, Scelioninae, Teleasinae, Telenominae). Platygastroid diversity will certainly rise in Spanish amber as abundant new material be-comes available from the El Soplao and San Just outcrops. The name Jordanoscelio nom. nov. is proposed to replace the homonymous Microptera Kaddumi for a Jordanian amber (Early Cretaceous) genus of Scelionidae, resulting in Jordanoscelio attiki (Kaddumi) comb. nov. •
The extinct tanaidomorphan diversity from Early Cretaceous Spanish amber, currently comprising 26 specimens, is reassessed. The fossil family Alavatanaidae Vonk & Schram, 2007, described from Spanish amber, is revised on account of new preparation of type specimens and the discovery of new material. The described tanaidomorphan taxa are classified within the superfamily Paratanaoidea. An emended diagnosis for Alavatanaidae is provided, as well as for the genera Alavatanais Vonk & Schram, 2007 and Proleptochelia Vonk & Schram, 2007, and their respective species Alavatanais carabe Vonk & Schram, 2007 and Proleptochelia tenuissima Vonk & Schram, 2007. Three new species, two of them classified in a new genus each, are described: Alavatanais margulisae Sánchez-García, Peñalver & Delclòs sp. nov., Eurotanais terminator Sánchez-García, Peñalver & Delclòs gen. et sp. nov. and Electrotanais monolithus Sánchez-García, Peñalver & Delclòs gen. et sp. nov. Proleptochelia euskadiensis Vonk & Schram, 2007 is considered a junior synonym of A. carabe, and the genus Proleptochelia, together with its type and only species P. tenuissima, is left without familial placement within Paratanaoidea. Within this superfamily, Alavatanaidae is closely related to Leptocheliidae. Also, morphological variability due to sexual dimorphism in the studied paratanaoids has been determined. Multiple lines of taphonomic and palaeobiological evidence indicate that the Spanish amber tanaids were most likely inhabitants of wet or moist forest floors.
The order Dermaptera (earwigs) is recorded for the first time from the Early Cretaceous ambers of Spain.
Autrigonoforceps iberica Engel et Peris gen. et sp. n. is described and figured from a single, putative ♀
preserved in Albian amber from Peñacerrada I. Due to its trimerous tarsi and the absence of ocelli, the
placement of the new fossil within the Neodermaptera is clear. Although it seems close to Labiduridae, its
confident placement in any family is impossible given the limited visibility of several critical characters.
The species is compared with the labidurid Myrrholabia from mid-Cretaceous amber of Myanmar.
Four new species belonging to the enigmatic fossil spider family Lagonomegopidae Eskov & Wunderlich, 1995 are described from Albian Spanish amber. Two new genera are created: Spinomegops gen. nov., based on two specimens described as S. arcanus sp. nov. from Álava amber (Peñacerrada I outcrop, Burgos), and S. aragonensis sp. nov. from San Just amber (Teruel); and Soplaogonomegops gen. nov., represented by the type species S. unzuei sp. nov. from El Soplao amber (Cantabria). A single specimen from Álava amber is tentatively assigned to Lagonomegops Eskov & Wunderlich, 1995 and described as L.? cor sp. nov. We confirm the existence of previously contentious numerous tarsal and metatarsal trichobothria on Burlagonomegops alavensis Penney, 2005, and reinterpret the mouthpart morphology of Grandoculus chemahawinensis Penney, 2004. In light of our new data, the family diagnosis for Lagonomegopidae is emended and the family Grandoculidae Penney, 2011 is synonymized with Lagonomegopidae.http://www.zoobank.org/urn:lsid:zoobank.org:pub:67DF253C-4DD8-46B5-8FD4-540D53F6E90B
Although their functional importance in ecosystems is increasingly recognized, soil-dwelling micro-arthropods are usually poorly known in comparison with their above-ground counterparts. Collembola constitute a significant and species-rich component of the soil biodiversity, but it remains a woefully understudied group because of the taxonomic impediment. The ever-increasing use of molecular taxonomic tools, such as DNA barcoding, provides a possible solution. Here, we test the use of this approach through a diversity survey of Collembola from the vicinity of Churchill, Manitoba, Canada, and compare the results with previous surveys in the same area and in other sub-Arctic regions. The systematic barcoding campaign at Churchill revealed a diverse collembolan fauna consisting of 97 species-level MOTUs in six types of habitats. If all these MOTUs are confirmed as species, this richness would be far higher than prior records for Arctic Canada and could lead to reconsider the actual diversity of the group in Arctic environments.
The occurrence of amber in Sierra de Cantabria (álava, Basque Country) has been known for more than two decades but biological inclusions have only recently been found. The existence of crustaceans (amphipods and isopods), chelicerates (acari and arachnids), 12 orders of insects, and several bird feathers are reported in this preliminary study. In addition, there are leaf remains, molluscs, and a fair number of inorganic inclusions.
Pollen analysis of the clastic series indicates an age between upper Aptian—middle Albian, which allows an assignment of this stratigraphic unit to the Nograro Formation. Chemical analysis indicates that the amber has high maturity, which reflects its Cretaceous age. Chemical composition analysis also indicates an araucariacean origin, which is corroborated by pollen found within the amber deposit.
This new fossil site provides information for the reconstruction of paleocommunities of arthropods and sedimentary environments in the extreme south of the Basque-Cantabrian Basin during the Lower Cretaceous, characterized by coniferous forests with an understory of vascular cryptograms. Some of the identified arthropods add to the fossil record for various groups that are poorly known or unknown for this time period. This Lagerstätte constitutes one of the most important deposits of Mesozoic amber in the world.
Clover flea (Sminthurus viridis (L.) is a sporadic and at times serious pest of white clover in New Zealand. Clover flea feeding is reduced in the laboratory by application of foliar fertilisers. The possibility that this was related to potassium status was tested in outdoor conditions using potted clover plants sprayed with two general purpose fertilisers, Nitrosol® and Thrive®, potash, the insecticide diazinon and water. In one experiment, sprayed plants were placed in a paddock where clover flea were active while in the second, treated plants were surrounded by a barrier and clover flea released into the enclosure. Three treatments significantly reduced the incidence of feeding damage 7-9 days after treatment compared to the water treatment, with diazinon (42-57% reduction in the incidence of damage) more effective than Nitrosol® (26-44%) and potash (38%). There was no evidence the effect was related to potassium. Only Thrive® increased the amount of foliage.
This volume dealing with the 239 Nordic species of Entomobryomorpha and Symphypleona completes the survey which was started with Part 1, Poduromorpha, which appeared ten years ago (Fjellberg, 1998a). The number of Collembola species being recorded in the Nordic countries have now reached 403 (a few more Poduromorpha are added since 1998). The detailed studies and use of mouthpart morphology in species diagnostics was introduced in Part 1 and is continued here. Structures of labium, labrum and maxilla are found to be particularly useful in diagnostics of higher taxa of Symphypleona. Colour photographs are used to illustrate some of the more characteristic species. Three new species are described (Desoria potapovi sp. nov., Desoria tolya sp. nov., Isotomurus graminis sp. nov.). The following new synonyms are established: Folsomia janstachi Potapov & Babenko, 2000 = Isotoma (now Folsomia) coeruleogrisea Hammer, 1938; Folsomia norvegica Altner, 1963 = Folsomia thalassophila Bagnall, 1940; Proisotoma admaritima Murphy, 1953 = Isotoma (now Cryptopygus) clavata Schött, 1893; Isotoma ruseki Fjellberg, 1979 = Isotoma (now Desoria) fennica Reuter, 1895; Isotoma inupikella Fjellberg, 1978 = Isotoma (now Desoria) violacea Tullberg, 1876; Isotoma germanica Hüther & Winter, 1961 = Isotoma (now Desoria) intermedia Schött, 1902; Entomobrya subarctica Stach, 1962 = Podura (now Entomobrya) nivalis Linnaeus, 1758.
It goes without saying that insects epitomize diversity, and with over a million documented species they stand out as one of the most remarkable lineages in the 3.5-billion-year history of life on earth (Figure 1). This reality is passé to even the layperson and is taken for granted in the same way none of us think much of our breathing as we go about our day, and yet insects are just as vital to our existence. Insects are simultaneously familiar and foreign to us, and while a small fraction are beloved or reviled, most are simply ignored. These inexorable evolutionary overachievers outnumber us all, their segmented body plan is remarkably labile, they combine a capacity for high rates of speciation with low levels of natural extinction, and their history of successes eclipses those of the more familiar ages of dinosaurs and mammals alike. It is their evolution - persisting over vast expanses of geological time and inextricably implicated in the diversification of other lineages - that stands as one of the most expansive subjects in biology.
The present study aims to discuss the phylogenetic relationships between higher taxa of the apterygote hexapods. Tt considers characters based on visceral anatomy and, to a lesser extent, reproductive behaviour and ontogeny. Cladistic analyses were performed using the computer program PAUP version 3.1.1. Taking into account 32 unordered and equally weighted characters, the possible assemblages of 8 apterygote taxa were studied in the presence of two additional pterygote taxa and of two representatives of myriapods (Lithobiomorpha and Symphyla), used as outgroups. The results of the analyses argue in favour of the monophyly of Protura and Collembola. Protura appear as distinctly separated from all other Hexapoda. Conversely, the groups Ellipura (Protura + Collembola), Diplura and Entognatha (Ellipura + Diplura) are not supported. The two dipluran taxa included (Campodeoidea and Japygoidea) are found as separate units whose positions relative either to Collembola or to Ectognatha, remain unresolved. The question of the monophyly of Archaeognatha and that of Zygentoma was not adressed here, because only one family of either order was considered. Likewise, the questionable monophyly of Zygentoma could not be studied, since only the family Lepismatidae was retained. The groupings Ectognatha and Dicondylia (Zygentoma + Pterygota) appear to be well supported. Our results confirm the paraphyly of the Apterygota and the close relationship between the Zygentoma and the Pterygota.
Antarctic arthropods (mites and springtails) have been the subject of numerous studies. However, by far, the most diverse and numerically dominant fauna in Antarctica are the limno-terrestrial microfauna (tardigrades, rotifers and nematodes). Although they have been the focus of several studies, there remains uncertainty of the actual number of species in Antarctica. Inadequate sampling and conserved morphology are the main cause of misclassification of species and underestimation of this diversity. Most species' distributional records are dominated by proximity to research stations or limited opportunistic collections, and therefore, an absence of records for a species may also be a consequence of the limitations of sampling. Limitations in fundamental knowledge of how many species are present and how widespread they are prevents any meaningful analyses that have been applied more generally to the arthropods within Antarctica, such as exploring ancient origins (at least pre-last glacial maximum) and tracking colonisation routes from glacial refugia. In this review, we list published species names and where possible the distribution of microfaunal (tardigrade, rotifer and nematode) species reported for Antarctica. Our current state of knowledge of Antarctic records (south of 60A degrees S) includes 28 bdelloid rotifers, 66 monogonont rotifers, 59 tardigrades and 68 nematodes. In the light of the difficulties in working with microfauna across such geographical scales, we emphasise the need for molecular markers to help understand the 'true levels' of diversity and suggest future directions for Antarctic biodiversity assessment and species discovery.
This paper is concerned with a small jumping mechanism. Microscopic observations of springtail leaping organs were conducted using a confocal leaser scanning microscope. A simple springtail mechanism using a spring and small electromagnet was produced based on the observations of leaping organ and the jumping analysis of the globular springtail. Jumping characteristics of the mechanism were examined with high-speed video camera system.
This paper describes jumping behaviour of the globular springtails. Direct observations on the jumping and climbing behaviour of springtails were conducted in the laboratory. The kinematics of jumping in tiny springtails was analyzed with high-speed video camera system. The vertical climbing behaviour was analyzed in contrast to the jumping behaviour. The jumping performance of springtails was revealed.
A new subgenus and species, Sminthurinus (Neokatianna) acantholaema Snider, is described from Auburn, Alabama. This subgenus exhibits morphological characteristics of both Sminthurinus and Katianna: subsegmented ANT IV, spine-like setae on dorsum of head, clavate tenent hairs, triangular bothriothrix ABC pattern, heel of mucro points straight down, palmate female subanal appendage, and bifid median seta on anal papilla. This species was taken from grass sweepings, Lee County, Auburn University Arboretum. /// Se describe de Auburn, Alabama, un nuevo subgénero y especie, Sminthurinus (Neokatianna) acantholaema Snider. Este subgénero tiene características morfológicas de ambas Sminthurinus y Katianna: subsegmentada ANT IV, setas como espinas en el dorso de la cabeza, pelos claveteados, patrones triangulares de botriotirix ABC, el talón de los puntos de mucro hacia abajo, el apéndice subanal de la hembra palmado, y bífida la seta media de la papila anal. Esta especie se obtuvo con un esparavel en hierbas en el Condado de Lee, en el Arboretum de la Universidad de Auburn.
The evolution of the holarctic cave Collembola of the subfamily Entomobryinae is analyzed. A number of evolutionary lines are shown, involving the two polyphyletic genera Pseudosinella and Sinella in Japan, North America, and Europe. Characteristics of these animals are of two types: cave dependent (responding rapidly to the cave environment) and cave independent (showing no effect of the cave environment). The evolution of the cave organisms is divided into three stages. The first stage represents the level of adaptation normally found in troglophile organisms, although some troglobites are found in the stage. All such forms are very limited in their cave distribution, and occupy a few caves around the periphery of major cave habitats. The second stage of evolution shows more cave adaptation, but the evolutionary pathways are varied, with convergence, parallelism, and divergence common. Most forms within this stage are troglobites, but there are a few troglophiles, and many of the organs characteristic of the stage occur as preadaptations in some putative ancestral forms. The members of this stage are abundant and relatively widespread. Within the third evolutionary stage convergence is universal, and the organs characteristic of these forms are limited to cave members of the family. Forms falling within this stage are relatively abundant but extremely limited in distribution. The probable adaptive significance of several organ modifications characteristic of troglobite forms is discussed, and these structures are interpreted as positive adaptations to the new requirements of cave life which have the final result of closely limiting the animals to the cave environment.
The Sminthuridae, which comprises the largest of the two world-wide families in the suborder Symphypleona, contains 31 genera. Four of these, Collophora , Bothriovulsus , Vesicephalus , and Temeritas are described as new. This study was undertaken mainly to more accurately ascertain relationships within the family. As a result four subfamilies, the Sminthuridinae, the Katianninae, the Dicyrtominae, and the Sminthurinae, are recognized. Of these, the Sminthuridinae seems to have been the first group to become established and the Sminthurinae was relatively the more recent group. The material has been analyzed for indications as to probable age of the units that have been called genera and the place of origin. It seems likely that the generic units existed before the close of the Cretaceous and that the group originated in the north.
The book is organized into 10 chapters: general introduction; review of the literatire on springtails; evolution, systematics and biogeography; ecomorphology and anatomy; taxonomic methods and the species concept in Collembola; interactions between Collembola and the abiotic environment; interactions between Collembola and the biotic environment; reproduction, development and life histories; ecology and conservation; and ecotoxicology. There are three appendices: World genera of Collembola; regional checklists of Collembola; and laboratory/field studies on the effects of chemicals on Collembola.
An overview of the terrestrial and freshwater invertebrate fauna of the High Arctic archipelago of Svalbard is presented. Sixty seven additional species to the previous checklist are listed and the described terrestrial and freshwater invertebrate fauna of Svalbard now stands at 1,107 species. Species presented are cross referenced to the literature. A brief comparison with the invertebrate fauna of Greenland indicates that Svalbard may be under-represented in Hymenoptera, Hemiptera and Lepidoptera but over-represented in Collembola and Acari. However, since 82% of Svalbard primary source manuscripts originate from three locations along the west coast, there is a resulting likely bias in our knowledge of the invertebrate fauna. The west coast has a mild climate for the northerly latitude due to the influence of the West Spitsbergen Current, a northerly flowing branch of the North Atlantic Drift. The faunistically poorly known east coast is hypothesised to have a different invertebrate fauna due to the predominant winds and currents originating from the north east and hence this coast will have a different history of immigration and colonization from the west coast. The use of checklists is therefore cautioned due to possible sampling bias and omissions created by a concentration of work on popular groups and at a limited number of localities. However, this does not detract from their importance as baseline databases, especially during a period of rapid environmental change.
Three new genera and species of scolebythid wasps (Aculeata: Chrysidoidea) are described and figured from Cretaceous amber. Ectenobythus iberiensis gen. et sp. nov. is described from a female and putative male in Early Cretaceous (Albian) amber from the Peñacerrada I outcrop, Spain, while Necrobythus pulcher gen. et sp. nov. and Sphakelobythus limnopous gen. et sp. nov. are described from one putative male and two females in Late Cretaceous (Campanian) amber from Grassy Lake, Alberta, Canada. The new taxa are described and compared to related Cretaceous genera of Scolebythidae and coded for cladistic analysis with the full diversity of living and extinct species in the family. The resulting phylogeny supports the division of the family into two subfamilies (recognized informally by earlier authors), Scolebythinae Evans and Pristapenesiinae subfam. nov.
Resumen Se presenta la diversidad de avispas betílidas en ámbar del Cretácico Inferior (Albiense) de Moraza (Ámbar de Álava, España). Se han registrado un total de ocho especímenes en éste yacimiento y se asignan a los siguientes taxones: Lancepyris alavaensis, nueva especie; Liztor pilosus, nuevos género y especie; y Cretepyris martini, nuevos género y especie. Esto eleva a 48 el total de especies fósiles conocidas de betílidos. No sorprende, dada la antigüedad de los taxones que se tratan, que su asignación a una familia actual sea complicada, especialmente para Cretepyris. Inicialmente, la decisión para su asignación fue muy dudosa entre Bethylinae, por su venación más completa, y Epyrinae por la ausencia de inserción o carena longitudinal-media del clípeo, ausencia de constricción propodeal anterior, y ausencia de espinas postero-laterales (resaltando las dudas sobre la validez de Epyrinae tal como se define hoy en día). Por otra parte, la subfamilia fósil Lancepyrinae fue descrita recientemente en el ámbar libanés, y los especímenes del ámbar español encajan casi perfectamente en ese grupo, aunque mayormente en plesiomorfías, sugiriendo que el erguimiento de esta subfamilia puede tener un valor limitado.