An early bothremydid from the Arlington Archosaur Site of Texas (original) (raw)
Related papers
A new bothremydid turtle (Pleurodira) from the Olmos Formation (upper Campanian) of Coahuila, Mexico
Cretaceous Research, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
NEW BOTHREMYDID TURTLE (TESTUDINES, PLEURODIRA) FROM THE PALEOCENE OF NORTHEASTERN COLOMBIA
A new turtle, Puentemys mushaisaensis, from the middle to late Paleocene Cerrejó n Formation of Colombia, is described on the basis of a partial skull and many partial to nearly complete carapaces and plastrons representing multiple ontogenetic stages. Whereas P. mushaisaensis is unique in aspects of its shell morphology, it shares many diagnostic characteristics of bothremydid pleurodirans, including a long exoccipital-quadrate contact, a very low and rounded almost circular carapace, and a thinner internal bone cortex than that of the external cortex in both the carapace and plastron. With a maximum carapacial length of 151 cm, P. mushaisaensis is the largest known bothremydid turtle and represents the first occurrence of bothremydids in the Paleogene of South American tropics. Results from a cladistic analysis of bothremydids indicate that P. mushaisaensis shares a close relationship with Foxemys mechinorum from the Late Cretaceous of Europe, indicating a wide-spread geographical distribution for bothremydines during the Late Cretaceous-Paleocene.
Bulletin of the Peabody Museum of Natural History, 2011
A nearly complete fossil soft-shelled turtle (Trionychidae) from the Eocene Washakie Formation of Wyoming is described and identified as Oliveremys uintaensis, comb. nov. Previously known only from a single shell specimen, O. uintaensis can now be diagnosed using both skull and shell characteristics, including callosified but unsculptured xiphiplastra. “Trionyx” tritor “T.” franciscae, “T.” nelsoni and “T.” scutumantiquum are identified as junior synonyms of O. uintaensis. Parsimony and Bayesian analyses place O. uintaensis and all of its junior synonyms along with multiple previously scored fossil trionychid taxa. Reinterpretation of three characters within the matrix, as well as the addition of fossil taxa, resulted in novel relationships. These relationships were not recovered when only extant trionychids were included in a reinterpreted matrix or when fossil taxa were added without reinterpretation. The results indicate that the addition of fossil taxa is sometimes necessary to detect changes caused by other revisions to the character matrix.
PeerJ, 2016
Bothremydidae is a clade of extinct pleurodiran turtles known from the Cretaceous to Paleogene of Africa, Europe, India, Madagascar, and North and South America. The group is most diverse during the Late Cretaceous to Paleogene of Africa. Little is known, however, about the early evolution of the group. We here figure and describe a fossil turtle from early Late Cretaceous deposits exposed at MacFarlane Mine in Cedar Canyon, southwestern Utah, USA. The sediments associated with the new turtle are utilized to infer its stratigraphic provenience and the depositional settings in which it was deposited. The fossil is compared to previously described fossil pleurodires, integrated into a modified phylogenetic analysis of pelomedusoid turtles, and the biogeography of bothremydid turtles is reassessed. In light of the novel phylogenetic hypotheses, six previously established taxon names are converted to phylogenetically defined clade names to aid communication. The new fossil turtle can be...
The fossil record of solemydid turtles is primarily based on isolated fragments collected from Late Jurassic to Late Cretaceous sediments throughout North America and Europe and little is therefore known about the morphology and evolutionary history of the group. We here provide a detailed description of the only known near-complete solemydid skeleton, which was collected from the Lower Cretaceous (Aptian–Albian) Antlers Formation of Texas during the midtwentieth century, but essentially remains undescribed to date. Though comparison is limited, the skeleton is referred to Naomichelys speciosa, which is based on an isolated entoplastron from the Lower Cretaceous (Aptian–Albian) Kootenai (Cloverly) Formation of Montana. The absence of temporal emarginations, contribution of the jugals to the orbits, and a clear subdivision of the middle and inner cavities, and the presence of elongate postorbitals, posteriorly expanded squamosals, a triangular fossa at the posterior margin of the squamosals, an additional pair of tubercula basioccipitale that is formed by the pterygoids, foramina pro ramo nervi vidiani (VII) that are visible in ventral view, shell sculpturing consisting of high tubercles, a large entoplastron with entoplastral scute, V-shaped anterior peripherals, and limb osteoderms with tubercular sculpture diagnose Naomichelys speciosa as a representative of Solemydidae. The full visibility of the parabasisphenoid complex in ventral view, the presence of an expanded symphyseal shelf, and the unusual ventromedial folding of the coronoid process are the primary characteristics that distinguish Naomichelys speciosa from the near-coeval European taxon Helochelydra nopcsai.
Chinlechelys from the Upper Triassic of New Mexico, USA, and the origin of turtles
Palaeontologia Electronica
Chinlechelys tenertesta is a turtle from the Upper Triassic Bull Canyon Formation of the Chinle Group of eastern New Mexico, USA, which has largely been ignored in recent studies of the phylogenetic position of turtles (Testudinata) within the Tetrapoda. Here, we present the first comprehensive description of the morphology of Chinlechelys tenertesta and reaffirm its unequivocal support for the composite model of costal bone formation in turtles. We also document the presence in Chinlechelys tenertesta of separate ribs reminiscent of those of Odontochelys semitestacea, a Late Triassic prototurtle from China, and costal plates, as would be expected under the composite model. This indicates that the two-phase embryological model of costal and plastral bone formation approximately corresponds to the formation of the endochondal rib and plastral primary ossifications and then the later dermal formation of the plastral and costal plates, as is suggested by the composite model. We challenge the identification of Permian Eunotosaurus africanus as a stem turtle and instead suggest that it is a caseid synapsid. We do not consider Pappochelys rosinae to be a close relative of turtles. It more closely resembles the basal placodont sauropterygians, particularly Palatodonta bleekeri. Indeed, phylogenetic analysis based on correctly coded character states places Pappochelys rosinae in the Sauropterygia as the sister taxon of placodonts. The morphology of Chinlechelys tenertesta supports the placement of Testudines outside of crown Sauria, as a taxon derived from pareiasaurs based on the morphology of the dorsal osteoderms and skull roof.
Royal Society Open Science, 2019
Resolving the phylogeny of sea turtles is uniquely challenging given the high potential for the unification of convergent lineages due to systematic homoplasy. Equivocal reconstructions of marine turtle evolution subsequently inhibit efforts to establish fossil calibrations for molecular divergence estimates and prevent the accurate reconciliation of biogeographic or palaeoclimatic data with phylogenetic hypotheses. Here we describe a new genus and species of marine turtle, Asmodochelys parhami , from the Upper Campanian Demopolis Chalk of Alabama and Mississippi, USA represented by three partial shells. Phylogenetic analysis shows that A. parhami belongs to the ctenochelyids, an extinct group that shares characteristics with both pan-chelonioids and pan-cheloniids. In addition to supporting Ctenochelyidae as a sister taxon of Chelonioidea, our analysis places Protostegidae outside of the Chelonioidea crown group and recovers Allopleuron hofmanni as a stem dermochelyid. Gap excess r...
Sea turtles, specifically members of the family Protostegidae, reached gigantic size (up to 4 m long) during the Late Cretaceous and have been documented extensively from the deposits of the Western Interior Seaway in the mid-continent of North America (e.g., Wieland, 1902, 1903, 1906; Williston, 1914; Zangerl, 1953; Hirayama, 1997; Lehman and Tomlinson, 2004). Here, we describe the first record of a giant sea turtle from New Mexico, compare it to other protostegids and briefly discuss their significance to the distribution of North American protostegids.
Two new plastomenine softshell turtles from the Paleocene of Montana and Wyoming
Bulletin of The Peabody Museum of Natural History, 2009
Softshell turtles (Trionychidae) are a highly enigmatic clade of reptiles characterized by a reduced shell, the loss of nearly all scales and scutes, and the development of a proboscis (Ernst and . Trionychids generally prefer riverine habitats and are thus commonly found in fluvial and near-shore marine sediments. Furthermore, because of the unique surface texture and subsur-face structure ) of the shell, trionychids are easily recognized in the fossil record.