Dataset Information

An early bothremydid from the Arlington Archosaur Site of Texas.

ABSTRACT: Four turtle taxa are previously documented from the Cenomanian Arlington Archosaur Site (AAS) of the Lewisville Formation (Woodbine Group) in Texas. Herein, we describe a new side-necked turtle (Pleurodira), Pleurochayah appalachius gen. et sp. nov., which is a basal member of the Bothremydidae. Pleurochayah appalachius gen. et sp. nov. shares synapomorphic characters with other bothremydids, including shared traits with Kurmademydini and Cearachelyini, but has a unique combination of skull and shell traits. The new taxon is significant because it is the oldest crown pleurodiran turtle from North America and Laurasia, predating bothremynines Algorachelus peregrinus and Paiutemys tibert from Europe and North America respectively. This discovery also documents the oldest evidence of dispersal of crown Pleurodira from Gondwana to Laurasia. Pleurochayah appalachius gen. et sp. nov. is compared to previously described fossil pleurodires, placed in a modified phylogenetic analysis of pelomedusoid turtles, and discussed in the context of pleurodiran distribution in the mid-Cretaceous. Its unique combination of characters demonstrates marine adaptation and dispersal capability among basal bothremydids.

SUBMITTER: Adrian B

PROVIDER: S-EPMC8137945 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

An early bothremydid from the Arlington Archosaur Site of Texas.

Adrian Brent B Smith Heather F HF Noto Christopher R CR Grossman Aryeh A

Scientific reports 20210520 1

Four turtle taxa are previously documented from the Cenomanian Arlington Archosaur Site (AAS) of the Lewisville Formation (Woodbine Group) in Texas. Herein, we describe a new side-necked turtle (Pleurodira), Pleurochayah appalachius gen. et sp. nov., which is a basal member of the Bothremydidae. Pleurochayah appalachius gen. et sp. nov. shares synapomorphic characters with other bothremydids, including shared traits with Kurmademydini and Cearachelyini, but has a unique combination of skull and ...[more]

PMID: 34017016

Similar Datasets

Project description:BackgroundThe origin and early radiation of archosaurs and closely related taxa (Archosauriformes) during the Triassic was a critical event in the evolutionary history of tetrapods. This radiation led to the dinosaur-dominated ecosystems of the Jurassic and Cretaceous, and the high present-day archosaur diversity that includes around 10,000 bird and crocodylian species. The timing and dynamics of this evolutionary radiation are currently obscured by the poorly constrained phylogenetic positions of several key early archosauriform taxa, including several species from the Middle Triassic of Argentina (Gracilisuchus stipanicicorum) and China (Turfanosuchus dabanensis, Yonghesuchus sangbiensis). These species act as unstable 'wildcards' in morphological phylogenetic analyses, reducing phylogenetic resolution.ResultsWe present new anatomical data for the type specimens of G. stipanicicorum, T. dabanensis, and Y. sangbiensis, and carry out a new morphological phylogenetic analysis of early archosaur relationships. Our results indicate that these three previously enigmatic taxa form a well-supported clade of Middle Triassic archosaurs that we refer to as Gracilisuchidae. Gracilisuchidae is placed basally within Suchia, among the pseudosuchian (crocodile-line) archosaurs. The approximately contemporaneous and morphologically similar G. stipanicicorum and Y. sangbiensis may be sister taxa within Gracilisuchidae.ConclusionsOur results provide increased resolution of the previously poorly constrained relationships of early archosaurs, with increased levels of phylogenetic support for several key early pseudosuchian clades. Moreover, they falsify previous hypotheses suggesting that T. dabanensis and Y. sangbiensis are not members of the archosaur crown group. The recognition of Gracilisuchidae provides further support for a rapid phylogenetic diversification of crown archosaurs by the Middle Triassic. The disjunct distribution of the gracilisuchid clade in China and Argentina demonstrates that early archosaurs were distributed over much or all of Pangaea although they may have initially been relatively rare members of faunal assemblages.

Project description:Archosauria (birds, crocodilians and their extinct relatives) form a major part of terrestrial ecosystems today, with over 10 000 living species, and came to dominate the land for most of the Mesozoic (over 150 Myr) after radiating following the Permian-Triassic extinction. The archosaur skull has been essential to this diversification, itself diversified into myriad forms. The archosauriform Euparkeria capensis from the Middle Triassic (Anisian) of South Africa has been of great interest since its initial description in 1913, because its anatomy shed light on the origins and early evolution of crown Archosauria and potentially approached that of the archosaur common ancestor. Euparkeria has been widely used as an outgroup in phylogenetic analyses and when investigating patterns of trait evolution among archosaurs. Although described monographically in 1965, subsequent years have seen great advances in the understanding of early archosaurs and in imaging techniques. Here, the cranium and mandible of Euparkeria are fully redescribed and documented using all fossil material and computed tomographic data. Details previously unclear are fully described, including vomerine dentition, the epiptergoid, number of premaxillary teeth and palatal arrangement. A new diagnosis and cranial and braincase reconstruction is provided, and an anatomical network analysis is performed on the skull of Euparkeria and compared with other amniotes. The modular composition of the cranium suggests a flexible skull well adapted to feeding on agile food, but with a clear tendency towards more carnivorous behaviour, placing the taxon at the interface between ancestral diapsid and crown archosaur ecomorphology, corresponding to increases in brain size, visual sensitivity, upright locomotion and metabolism around this point in archosauriform evolution. The skull of Euparkeria epitomizes a major evolutionary transition, and places crown archosaur morphology in an evolutionary context.

Project description:BACKGROUND: Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (>10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3-247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. METHODOLOGY/PRINCIPAL FINDINGS: We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the 'sail' of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. CONCLUSIONS/SIGNIFICANCE: Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian-Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs.

Project description:ImportanceTexas' 2021 ban on abortion in early pregnancy may demonstrate how patterns of abortion might change following the US Supreme Court's June 2022 decision overturning Roe v Wade.ObjectiveTo assess changes in the number of abortions and changes in the percentage of out-of-state abortions among Texas residents performed at 12 or more weeks of gestation in the first 6 months following implementation of Texas Senate Bill 8 (SB 8), which prohibited abortions after detection of embryonic cardiac activity.Design, setting, and participantsRetrospective study of a sample of 50 Texas and out-of-state abortion facilities using an interrupted time series analysis to assess changes in the number of abortions, and Poisson regression to assess changes in abortions at 12 or more weeks of gestation. Data included 68 820 Texas facility-based abortions and 11 287 out-of-state abortions among Texas residents during the study period from September 1, 2020, to February 28, 2022.ExposuresAbortion care obtained after (September 2021-February 2022) vs before (September 2020-August 2021) implementation of SB 8.Main outcomes and measuresPrimary outcomes were changes in the number of facility-based abortions for Texas residents, in Texas and out of state, in the month after implementation of SB 8 compared with the month before. The secondary outcome was the change in the percentage of out-of-state abortions among Texas residents obtained at 12 or more weeks of gestation during the 6-month period after the law's implementation.ResultsBetween September 2020 and August 2021, there were 55 018 abortions in Texas and 2547 out-of-state abortions among Texas residents. During the 6 months after SB 8, there were 13 802 abortions in Texas and 8740 out-of-state abortions among Texas residents. Compared with the month before implementation of SB 8, the number of Texas facility-based abortions significantly decreased from 5451 to 2169 (difference, -3282 [95% CI, -3171 to -3396]; incidence rate ratio [IRR], 0.43 [95% CI, 0.36-0.51]) in the month after SB 8 was implemented. The number of out-of-state abortions among Texas residents significantly increased from 222 to 1332 (difference, 1110 [95% CI, 1047-1177]; IRR, 5.38 [95% CI, 4.19-6.91]). Overall, the total documented number of Texas facility-based and out-of-state abortions among Texas residents significantly decreased from 5673 to 3501 (absolute change, -2172 [95% CI, -2083 to -2265]; IRR, 0.67 [95% CI, 0.56-0.79]) in the first month after SB 8 was implemented compared with the previous month. Out-of-state abortions among Texas residents obtained at 12 or more weeks of gestation increased from 17.1% (221/1291) to 31.0% (399/1289) (difference, 178 [95% CI, 153-206]) during the period between September 2021 and February 2022 (P < .001 for trend).Conclusions and relevanceAmong a sample of abortion facilities, the 2021 Texas law banning abortion in early pregnancy (SB 8) was significantly associated with a decrease in the documented total of facility-based abortions in Texas and obtained by Texas residents in surrounding states in the first month after implementation compared with the previous month. Over the 6 months following SB 8 implementation, the percentage of out-of-state abortions among Texas residents obtained at 12 or more weeks of gestation significantly increased.

Dataset Information

An early bothremydid from the Arlington Archosaur Site of Texas.

Publications

An early bothremydid from the Arlington Archosaur Site of Texas.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets