A new bothremydid turtle (Pleurodira) from the Olmos Formation (upper Campanian) of Coahuila, Mexico (original) (raw)
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Nonmarine turtles from the Aguja Formation (Late Cretaceous, Campanian) of Chihuahua, Mexico
Journal of South American Earth Sciences, 2020
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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.
The first Paleogene (Oligocene) sea turtle record of South America
2018
The evolution and occurrence of fossil sea turtles at the Pacific margin of South America is poorly known and restricted to Neogene (Miocene) findings from Perú. Here we report and describe the first record of Paleogene (Late Oligocene, ~24 Ma) sea turtle remains. The fossil material corresponds to a single, isolated and well-preserved costal bone found at the Montañita/Olón locality, Santa Elena Province, Ecuador. Comparisons with other Oligocene and extant representatives allow us to confirm that belong to a sea turtle characterized by: lack of lateral ossification, allowing the dorsal exposure of the distal end of ribs; dorsal surface of bone sculptured, changing from dense vermiculation at the vertebral scute region and changing to anastomosing pattern of grooves at the most lateral portion of the costal. This fossil finding shows the high potential that the Ecuadorian Paleogene outcrops have in order to explore the evolution and paleobiogeography distribution of sea turtles by ...
A new platychelyid turtle (Pan-Pleurodira) from the Late Jurassic (Kimmeridgian) of Oaxaca, Mexico
Papers in Palaeontology, 2016
Until recently, the record of Mesozoic turtles in Mexico has been restricted to the Cretaceous. New discoveries in the Sabinal Formation (Tlaxiaco, Oaxaca) have extended the record into the Kimmeridgian (Late Jurassic). The Sabinal Formation is part of the Tlaxiaco Basin, which was a depocenter of continental and marine sediments dominated by transgressive-regressive marine conditions during the Jurassic-Cretaceous. The new turtle described here consists of an almost complete carapace associated with a plastron. Based on the unique combination of characters, this turtle is identified as a new species of Platychelyidae here named Notoemys tlaxiacoensis. Platychelyid characters in this specimen include the presence of the sulcus between vertebral 3 and 4 located on neural 6, the presence of a central plastral fontanelle, and a pair of reduced mesoplastra. The occurrence of Kimmeridgian platychelyids in Mexico confirms that the Hispanic Corridor acted as a connection between Tethyan and Palaeopacific faunas.
Bulletin of the New Mexico Museum of Natural History and Science, 2016
The late Pleistocene of northern Mexico is relatively poorly understood, and represented by only a few fossil localities. One such locality is Térapa, located in east-central Sonora. The deposit dates to between 43,000 and 40,000 years old (Rancholabrean) and yields a rich fossil fauna of over 60 identified taxa, dominated by birds and large mammals. Geologic evidence at the site indicates a marshland with permanent sources of calm freshwater, which is supported by the presence of fossil remains of freshwater invertebrates, fishes, frogs, crocodilians and turtles. Previous studies have reported fossil turtles representing two families: Emydidae and Kinosternidae. Both of these families are represented in the extant fauna of Sonora. Here, we present the remains of two additional families of turtles from Térapa, Chelydridae and Trionychidae, both of which are absent today in the naturally-occurring fauna of Sonora. The extralimital presence of these families at Térapa indicates a significant biogeographical shift between the late Pleistocene and the present day. Previous studies have noted the similarly unusual discovery of crocodilians at Térapa, and proposed that its presence might be the result of dispersal into Sonora via coastal and riparian routes. We suggest a similar migration pattern might explain the presence of chelydrids and trionychids at the site, with the turtles dispersing into Sonora either from the north or from the south, and we discuss evidence for both scenarios.
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.
Cretaceous Research, 2017
A new genus and species of panchelid turtle (Mendozachelys wichmanni gen. et sp. nov.) from the upper Campanianelower Maastrichtian Loncoche Formation (southern Mendoza Province, Argentina) is described here. This species is represented by only one complete and articulated large specimen (carapace length estimated in 950 mm) that was recovered from tidal flat deposits. A detailed morphological and osteohistological description is made, recognizing autapomorphic characters that allow differentiating this taxon from the rest of extant and extinct panchelids. Osteohistological characters suggest an aquatic to semi-aquatic life style for Mendozachelys wichmanni gen. et sp. nov. Phylogenetic analysis based on morphological data suggested that this new taxon is nested within crown Chelidae. Both phylogenetic signals (morphological and molecular) about the assessment of long-necked chelids monophyly or polyphyly are discussed.
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...
Journal of Vertebrate Paleontology, 1998
A new locality named EI Pel illal (Cerro del Pueblo Formation, Late Cretaceous, Campanian) in the southeastern area of the State of Coahuila, Mexico yields an assemblage of vertebrates that is important for correlation due to its frequent occurrence in other localities along the Cerro del Pueblo Formation outcrops. It is located in the Municipio de Ramos Arizpe, Coahuila. Among the vertebrates found are: fishes (Lepisosteidae; Amiidae [cf. Melvius sp.]); turtles (Trionychidae, Chelydridae [cf. Protoehelydra sp.], Kinosternoidea [cf. Hoplo- ehelys sp.], an undetermined kinosternoid genus, and ?Pleurosternidae [Compsemys vieta]) ; Crocodilians Neosu- chia (Goniopholididae) ; and Eu suchia and a pterosaur (Pterodactyloidea). Dinosaurs found incl ude a hadrosaurine hadrosaur, a new Troodontidae, and other indeterminate theropods. The El Pelillal Locality is interpreted as a fre shwater environment possibly influenced by tides. The fauna of the EI Pelillal loca lity, Cerro del Puebl o Formation, resembles southern U.S . Campanian-Maastrichtian faunas but lack s the prevalence of baenid, adocid, Basilemys and Nanhsuingchelyd turtles.