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Pinheiro FL, Eltink E, Paes-Neto VD, Machado AF, Simões TR, Pierce SE. Interrelationships among Early Triassic faunas of Western Gondwana and Laurasia as illuminated by a new South American benthosuchid temnospondyl. Anat Rec (Hoboken) 2024; 307:726-743. [PMID: 38240478 DOI: 10.1002/ar.25384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/29/2023] [Accepted: 12/30/2023] [Indexed: 03/16/2024]
Abstract
The End-Permian Mass Extinction marked a critical turning point in Earth's history, and the biological recovery that followed the crisis led to the emergence of several modern vertebrate and invertebrate taxa. Even considering the importance of the Early Triassic biotic recovery for the evolution of modern faunas and floras, our knowledge of this event is still hindered by the sparse sampling of crucial geological formations. This leaves our understanding of Early Triassic ecosystems fundamentally biased toward productive and historically well-explored geological units. Recent surveys in poorly known Gondwanan localities, such as those within the Sanga do Cabral Formation in southern Brazil, have unveiled insights into Early Triassic terrestrial ecosystems, shedding light on a diverse and previously unknown tetrapod fauna. Here, we report the discovery of a new temnospondyl genus and species in the Lower Triassic Sanga do Cabral Formation. The new taxon can be confidently assigned to the Benthosuchidae, a stereospondyl clade with a distribution previously restricted to the East European Platform. Phylogenetic analysis confirms the relationship of the new genus to the trematosaurian lineage, being closely related to the genus Benthosuchus. Our results raise questions about the biogeographical history of stereospondyls after the End-Permian Mass Extinction and suggest a potential connection between Russian and South American Early Triassic faunas. Further investigations are needed to thoroughly explore the potential dispersal routes that may explain this seemingly unusual biogeographical pattern.
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Affiliation(s)
- Felipe L Pinheiro
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, Rio Grande do Sul, Brazil
| | - Estevan Eltink
- Colegiado de Ecologia, Universidade Federal do Vale do São Francisco, Senhor do Bonfim, Bahia, Brazil
| | - Voltaire D Paes-Neto
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, Rio Grande do Sul, Brazil
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Arielli F Machado
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, Rio Grande do Sul, Brazil
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Tiago R Simões
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Stephanie E Pierce
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
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2
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Dunne EM, Thompson SED, Butler RJ, Rosindell J, Close RA. Mechanistic neutral models show that sampling biases drive the apparent explosion of early tetrapod diversity. Nat Ecol Evol 2023; 7:1480-1489. [PMID: 37500908 PMCID: PMC10482683 DOI: 10.1038/s41559-023-02128-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/20/2023] [Indexed: 07/29/2023]
Abstract
Estimates of deep-time biodiversity typically rely on statistical methods to mitigate the impacts of sampling biases in the fossil record. However, these methods are limited by the spatial and temporal scale of the underlying data. Here we use a spatially explicit mechanistic model, based on neutral theory, to test hypotheses of early tetrapod diversity change during the late Carboniferous and early Permian, critical intervals for the diversification of vertebrate life on land. Our simulations suggest that apparent increases in early tetrapod diversity were not driven by local endemism following the 'Carboniferous rainforest collapse'. Instead, changes in face-value diversity can be explained by variation in sampling intensity through time. Our results further demonstrate the importance of accounting for sampling biases in analyses of the fossil record and highlight the vast potential of mechanistic models, including neutral models, for testing hypotheses in palaeobiology.
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Affiliation(s)
- Emma M Dunne
- GeoZentrum Nordbayern, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK.
| | - Samuel E D Thompson
- Department of Life Sciences, Imperial College London, Ascot, UK
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Richard J Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - James Rosindell
- Department of Life Sciences, Imperial College London, Ascot, UK
| | - Roger A Close
- Department of Earth Sciences, University of Oxford, Oxford, UK
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3
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Buatois LA, Davies NS, Gibling MR, Krapovickas V, Labandeira CC, MacNaughton RB, Mángano MG, Minter NJ, Shillito AP. The Invasion of the Land in Deep Time: Integrating Paleozoic Records of Paleobiology, Ichnology, Sedimentology, and Geomorphology. Integr Comp Biol 2022; 62:297-331. [PMID: 35640908 DOI: 10.1093/icb/icac059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/19/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The invasion of the land was a complex, protracted process, punctuated by mass extinctions, that involved multiple routes from marine environments. We integrate paleobiology, ichnology, sedimentology, and geomorphology to reconstruct Paleozoic terrestrialization. Cambrian landscapes were dominated by laterally mobile rivers with unstable banks in the absence of significant vegetation. Temporary incursions by arthropods and worm-like organisms into coastal environments apparently did not result in establishment of continental communities. Contemporaneous lacustrine faunas may have been inhibited by limited nutrient delivery and high sediment loads. The Ordovician appearance of early land plants triggered a shift in the primary locus of the global clay mineral factory, increasing the amount of mudrock on the continents. The Silurian-Devonian rise of vascular land plants, including the first forests and extensive root systems, was instrumental in further retaining fine sediment on alluvial plains. These innovations led to increased architectural complexity of braided and meandering rivers. Landscape changes were synchronous with establishment of freshwater and terrestrial arthropod faunas in overbank areas, abandoned fluvial channels, lake margins, ephemeral lakes, and inland deserts. Silurian-Devonian lakes experienced improved nutrient availability, due to increased phosphate weathering and terrestrial humic matter. All these changes favoured frequent invasions to permament establishment of jawless and jawed fishes in freshwater habitats and the subsequent tetrapod colonization of the land. The Carboniferous saw rapid diversification of tetrapods, mostly linked to aquatic reproduction, and land plants, including gymnosperms. Deeper root systems promoted further riverbank stabilization, contributing to the rise of anabranching rivers and braided systems with vegetated islands. New lineages of aquatic insects developed and expanded novel feeding modes, including herbivory. Late Paleozoic soils commonly contain pervasive root and millipede traces. Lacustrine animal communities diversified, accompanied by increased food-web complexity and improved food delivery which may have favored permanent colonization of offshore and deep-water lake environments. These trends continued in the Permian, but progressive aridification favored formation of hypersaline lakes, which were stressful for colonization. The Capitanian and end-Permian extinctions affected lacustrine and fluvial biotas, particularly the invertebrate infauna, although burrowing may have allowed some tetrapods to survive associated global warming and increased aridification.
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Affiliation(s)
- Luis A Buatois
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Neil S Davies
- Department of Earth Sciences, University of Cambridge, Cambridge, Cambridgeshire CB2 3EQ, UK
| | - Martin R Gibling
- Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Verónica Krapovickas
- Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA, Argentina
| | - Conrad C Labandeira
- Department of Paleobiology, Smithsonian Institution, Washington DC 20013-7012, USA.,Department of Entomology and BEES Program, University of Maryland, College Park, Maryland 21740, USA.,College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Robert B MacNaughton
- Geological Survey of Canada (Calgary), Natural Resources Canada, Calgary, Alberta T2L 2A7, Canada
| | - M Gabriela Mángano
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Nicholas J Minter
- School of the Environment, Geography, and Geosciences, University of Portsmouth, Portsmouth, Hampshire PO1 3QL, UK
| | - Anthony P Shillito
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, UK
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4
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Hauffe T, Pires MM, Quental TB, Wilke T, Silvestro D. A quantitative framework to infer the effect of traits, diversity and environment on dispersal and extinction rates from fossils. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13845] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Torsten Hauffe
- Department of Biology University of Fribourg and Swiss Institute of Bioinformatics Fribourg Switzerland
| | - Mathias M. Pires
- Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas Campinas Brazil
| | - Tiago B. Quental
- Departamento de Ecologia, Universidade de São Paulo São Paulo Brazil
| | - Thomas Wilke
- Department of Animal Ecology and Systematics, Justus Liebig University Germany
| | - Daniele Silvestro
- Department of Biology University of Fribourg and Swiss Institute of Bioinformatics Fribourg Switzerland
- Department of Biological and Environmental Sciences University of Gothenburg and Gothenburg Global Biodiversity Centre Gothenburg Sweden
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5
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Li XQ, Xiang XG, Zhang Q, Jabbour F, Ortiz RDC, Erst AS, Li ZY, Wang W. Immigration dynamics of tropical and subtropical Southeast Asian limestone karst floras. Proc Biol Sci 2022; 289:20211308. [PMID: 34982948 PMCID: PMC8727148 DOI: 10.1098/rspb.2021.1308] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 12/02/2021] [Indexed: 01/14/2023] Open
Abstract
Ex situ origins and dispersal of taxa have played important roles in the assembly of island-like biodiversity hotspots. Insular limestone karsts in Southeast Asia are hotspots of biodiversity and endemism, but the immigration processes of their unique floras are still poorly known. Here, we used Gesneriaceae as a proxy to investigate the immigration dynamics of tropical and subtropical Southeast Asian karst floras. We present the most comprehensive phylogenetic analysis of the Old World gesneriads to date based on twelve loci. By estimating divergence times and reconstructing ancestral states (habitat, soil type and range), we found that immigration into subtropical Southeast Asian karst floras first occurred in the Early Miocene, with two peaks in the Early-Middle Miocene and the Pliocene-Early Pleistocene, whereas immigration into tropical Southeast Asian karsts initiated in the Late Eocene, with two peaks in the Late Oligocene and the Late Miocene. We also discover that Southeast Asian karst biodiversity comprises immigrant pre-adapted lineages and descendants from local acid soil ancestors, although niche shift from acid soil to karst in tropical Southeast Asian islands was lacking. This study advances our understanding of the historical assembly of Southeast Asian karst floras.
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Affiliation(s)
- Xiao-Qian Li
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xiao-Guo Xiang
- Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang 330031, Jiangxi, People's Republic of China
| | - Qiang Zhang
- Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain, Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences, Guilin 541006, Guangxi, People's Republic of China
| | - Florian Jabbour
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, Paris 75005, France
| | - Rosa del C. Ortiz
- Missouri Botanical Garden, 4344 Shaw Blvd, St Louis, MO 63166-0299, USA
| | - Andrey S. Erst
- Central Siberian Botanical Garden, Russian Academy of Sciences, Zolotodolinskaya Street 101, Novosibirsk 630090, Russia
| | - Zhen-Yu Li
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
| | - Wei Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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6
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Gee BM. Returning to the roots: resolution, reproducibility, and robusticity in the phylogenetic inference of Dissorophidae (Amphibia: Temnospondyli). PeerJ 2021; 9:e12423. [PMID: 34820181 PMCID: PMC8582317 DOI: 10.7717/peerj.12423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 10/11/2021] [Indexed: 11/22/2022] Open
Abstract
The phylogenetic relationships of most Paleozoic tetrapod clades remain poorly resolved, which is variably attributed to a lack of study, the limitations of inference from phenotypic data, and constant revision of best practices. While refinement of phylogenetic methods continues to be important, any phylogenetic analysis is inherently constrained by the underlying dataset that it analyzes. Therefore, it becomes equally important to assess the accuracy of these datasets, especially when a select few are repeatedly propagated. While repeat analyses of these datasets may appear to constitute a working consensus, they are not in fact independent, and it becomes especially important to evaluate the accuracy of these datasets in order to assess whether a seeming consensus is robust. Here I address the phylogeny of the Dissorophidae, a speciose clade of Paleozoic temnospondyls. This group is an ideal case study among temnospondyls for exploring phylogenetic methods and datasets because it has been extensively studied (eight phylogenetic studies to date) but with most (six studies) using a single matrix that has been propagated with very little modification. In spite of the conserved nature of the matrix, dissorophid studies have produced anything but a conserved topology. Therefore, I analyzed an independently designed matrix, which recovered less resolution and some disparate nodes compared to previous studies. In order to reconcile these differences, I carefully examined previous matrices and analyses. While some differences are a matter of personal preference (e.g., analytical software), others relate to discrepancies with respect to what are currently considered as best practices. The most concerning discovery was the identification of pervasive dubious scorings that extend back to the origins of the widely propagated matrix. These include scores for skeletal features that are entirely unknown in a given taxon (e.g., postcrania in Cacops woehri) and characters for which there appear to be unstated working assumptions to scoring that are incompatible with the character definitions (e.g., scoring of taxa with incomplete skulls for characters based on skull length). Correction of these scores and other pervasive errors recovered a distinctly less resolved topology than previous studies, more in agreement with my own matrix. This suggests that previous analyses may have been compromised, and that the only real consensus of dissorophid phylogeny is the lack of one.
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Affiliation(s)
- Bryan M. Gee
- Burke Museum and Department of Biology, University of Washington, Seattle, WA, United States of America
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7
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Benson RBJ, Butler R, Close RA, Saupe E, Rabosky DL. Biodiversity across space and time in the fossil record. Curr Biol 2021; 31:R1225-R1236. [PMID: 34637736 DOI: 10.1016/j.cub.2021.07.071] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fossil record is the primary source of information on how biodiversity has varied in deep time, providing unique insight on the long-term dynamics of diversification and their drivers. However, interpretations of fossil record diversity patterns have been much debated, with a traditional focus on global diversity through time. Problems arise because the fossil record is spatially and temporally patchy, so 'global' diversity estimates actually represent the summed diversity across a set of geographically and environmentally distinct regions that vary substantially in number and identity through time. Furthermore, a focus on global diversity lumps the signal of ecological drivers at local and regional scales with the signal of global-scale processes, including variation in the distribution of environments and in provincialism (the extent of subdivision into distinct biogeographic regions). These signals cannot be untangled by studying global diversity measures alone. These conceptual and empirical concerns necessitate a shift away from the study of 'biodiversity through time' and towards the study of 'biodiversity across time and space'. Spatially explicit investigations, including analyses of local- and regional-scale datasets, are central to achieving this and allow analysis of geographic scale, location and the environmental parameters directly experienced by organisms. So far, research in this area has revealed the stability of species richness variation among environments through time, and the potential climatic and Earth-system drivers of changing biodiversity. Ultimately, this research program promises to address key questions regarding the assembly of biodiversity, and the contributions of local-, regional- and global-scale processes to the diversification of life on Earth.
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Affiliation(s)
- Roger B J Benson
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK.
| | - Richard Butler
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Roger A Close
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Erin Saupe
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Daniel L Rabosky
- Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
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8
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Multiple paths to morphological diversification during the origin of amniotes. Nat Ecol Evol 2021; 5:1243-1249. [PMID: 34312521 DOI: 10.1038/s41559-021-01516-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 06/11/2021] [Indexed: 02/06/2023]
Abstract
Early terrestrial vertebrates (amniotes) provide a classic example of diversification following adaptive zone invasion. The initial terrestrialization of vertebrates was closely followed by dietary diversification, as evidenced by a proliferation of craniomandibular and dental adaptations. However, morphological evolution of early amniotes has received limited study, in analyses with restricted taxonomic scope, leaving substantial questions about the dynamics of this important terrestrial radiation. We use novel analyses of discrete characters to quantify variation in evolutionary rates and constraints during diversification of the amniote feeding apparatus. We find evidence for an early burst, comprising high rates of anatomical change that decelerated through time, giving way to a background of saturated morphological evolution. Subsequent expansions of phenotypic diversity were not associated with increased evolutionary rates. Instead, variation in the mode of evolution became important, with groups representing independent origins of herbivory evolving distinctive, group-specific morphologies and thereby exploring novel character-state spaces. Our findings indicate the importance of plant-animal interactions in structuring the earliest radiation of amniotes and demonstrate the importance of variation in modes of phenotypic divergence during a major evolutionary radiation.
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9
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Brikiatis L. An early Pangaean vicariance model for synapsid evolution. Sci Rep 2020; 10:13091. [PMID: 32753752 PMCID: PMC7403356 DOI: 10.1038/s41598-020-70117-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/13/2020] [Indexed: 11/15/2022] Open
Abstract
Genetic isolation due to geographic separation (vicariance) is the best understood cause of vertebrate speciation. Nevertheless, it has never been demonstrated in the fossil record across a wide range of taxa. Here, by reviewing in-depth the available data of the Late Palaeozoic (~ 350–250 million years ago), I reconstructed an early Pangaean junction-disjunction palaeogeographic model and showed that it coincides strongly with time-calibrated cladograms of the Late Palaeozoic synapsids (the primitive ancestors of modern mammals). The temporal development of the vicariant topology seems to fit closely with the emergence rhythm of the recovered synapsid taxa, suggesting vicariance due to Pangaean separation as the cause of early amniote evolution. The inferred vicariant topology also accounts for the observed pattern in the North American marine biostratigraphic units. Accordingly, the model demonstrates the link between the evolution of life on Earth and palaeogeographic evolution and strongly supports allopatric speciation through vicariance as the prominent mode of amniote evolution. Furthermore, correlations between state-of-the-art biochronostratigraphic charts and this palaeogeographic model suggest that the arido-eustasy model can explain the mid-Permian biotic extinction event and depositional cycles, such as the pre-Zechstein of the Central European Basin.
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Maho S, Gee BM, Reisz RR. A new varanopid synapsid from the early Permian of Oklahoma and the evolutionary stasis in this clade. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191297. [PMID: 31824730 PMCID: PMC6837192 DOI: 10.1098/rsos.191297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Varanopids are a basal clade of small- to medium-sized non-therapsid synapsids, whose range extends from the late Pennsylvanian to the late middle Permian, and are found in North America, Russia, Europe and South Africa. The greatest varanopid diversity is observed at the fossiliferous cave deposits near Richards Spur, Oklahoma, well known for the preservation of a complex early Permian upland community. Two previously described varanopids, Mycterosaurus and Varanops, are known only from fragmentary disarticulated material at Richards Spur. A third putative varanopid, Basicranodon fortsillensis, represented by a partial parasphenoid, has been synonymized with Mycterosaurus longiceps. This study reports on a new varanopid taxon, represented by substantially more complete material, including three nearly complete skulls. Such comprehensive cranial material allows for a detailed study of the taxon and its relationship to other varanopids. This new varanopid bears great morphological similarity to Mesenosaurus romeri from the middle Permian Mezen River Basin of northern Russia. Phylogenetic analysis recovers a sister relationship between this taxon and Me. romeri. This relationship, in conjunction with a detailed morphological comparison, supports the placement of this taxon within Mesenosaurus, as a new species, Me. efremovi. These results reveal an unexpected extension of the geographical and temporal range of Mesenosaurus, contributing to our understanding of varanopid dispersal. The extended persistence of this basal clade of predatory synapsids, underscored by the apparent evolutionary stasis of this genus, is unusual among Palaeozoic tetrapods. This phenomenon implies an exceptionally high degree of extended ecological resilience across major faunal and environmental transitions.
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Affiliation(s)
- Sigi Maho
- Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road, Mississauga, Ontario, CanadaL5L 1C6
| | - Bryan M. Gee
- Department of Biology, University of Toronto at Mississauga, 3359 Mississauga Road, Mississauga, Ontario, CanadaL5L 1C6
| | - Robert R. Reisz
- International Centre of Future Science, Jilin University, 2699 Qianjin Avenue, Changchun, Jilin Province, People's Republic of China
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