New Material of the Platychelyid Turtle Notoemys zapatocaensis from the Early Cretaceous of Colombia; Implications for Understanding Pleurodira Evolution (original) (raw)
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American Museum Novitates, 2005
A carapace and posterior plastral lobe from the early Cretaceous Valanginian of northeastern Colombia is a new species of the pleurodire Notoemys. It is a pleurodire based on the sutured pelvis and xiphiplastral notch. Notoemys zapatocaensis, n.sp., differs from the other two species of Notoemys, N. oxfordiensis and N. laticentralis, in having a slightly serrated posterior margin, a very small third peripheral, no contact of costal 1 and peripheral 3, and protuberances developed on the pleural and vertebral scale areas.
Revue De Paleobiologie, 2013
Notoemys laticentralis, a basal pleurodiran turtle of the upper Jurassic from South-argentina, is reconsidered with respect to the evolutionary process of some structures : proportions of the skull, anatomy of the back skull, alone preserved, and of the neck. Comparison of these structures has been leaded in different groups of turtles, previously established as monophyletic. Before, some remarks are given, with examples, on the difficulty to establish the homologies, what appears in the comparisons. The family Notoemydidae is supported as distinct from the family platychelyidae and considered as including Notoemys laticentralis laticentralis, N. zapatocaensis and Caribemys.
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.
The Tyndall Glacier in the Torres del Paine National Park is an extremely fossiliferous area of the Chilean Patagonia. In this area numerous articulated and a few complete ichthyosaurs were found. Most individuals are adults and juveniles. However, a few neonates and females with embryos also occur. The ichthyosaur skeletons are associated with abundant belemnites, ammonites and inoceramid bivalves. Ganoid and teleost fishes are frequently found. The record of tree trunks and remains of land plants suggest an environment in close vicinity to the shore. The meltdown of Tyndall Glacier has exposed sedimentary rocks in an area of about 10 km2, which are part of the Zapata Formation (?145–99 Ma). During the field campaign of 2009 to Torres del Paine National Park, a complete, isolated forefin of a platypterygian ichthyosaur was discovered. The specimen represents one of the best‐preserved Platypterygius forefins from the Early Cretaceous and shows some features that are not preserved in other Platypterygius species. Nevertheless, some factors such as the small number of Platypterygius specimens that has been found (McGowan, 1972; Fernández and Aguirre‐ Urreta, 2007; Arkhangelsky et al., 2008), their incompleteness and, in consequence, the difficulty to judge the factor of morphological variability make an accurate and correct taxonomic identification difficult. The high amount of specimens and the good preservation of the Tyndall ichthyosaurs is thus crucial for the understanding of the diversity of paleocommunities of ichthyosaurs during the Early Cretaceous and may represent one of the most informative areas for Early Cretaceous ichthyosaurs in the world.
Freshwater turtles (Testudines: Pleurodira) in the Upper Cretaceous of Chilean Patagonia
Journal of South American Earth Sciences, 2020
We describe remains of freshwater turtles from the Upper Cretaceous of Chilean Patagonia. The fossils, which comprise isolated shell fragments and incomplete appendicular bones, were recovered from meandering fluvial deposits of the Dorotea Formation (upper Campanian–Danian), in the Río de Las Chinas Valley, Magallanes region. These remains represent the first records of Upper Cretaceous pan-chelid pleurodiran turtles in the Magallanes-Austral Basin. The shell fragments show a strong ornamentation of irregular polygons distributed over their entire external surface, and one of the peripheral plates is narrow and elongated. These features are consistent with traits described in Yaminuechelys, a chelid genus from the Upper Cretaceous and Paleogene of Argentinian Patagonia. In addition, the suprapygal plate presents sulci that mark the limits of the vertebral scute 5 and the marginal scutes 12 as in Yaminuechelys sulcipeculiaris. This finding represents the southernmost record of a spe...
The Anatomical Record, 2020
Pelomedusoides had a recognised diverse Early Cretaceous fauna of turtles in Northeast Brazil. Within them, the bothremydid Cearachelys placidoi has a relatively abundant record. This diversity contrasts with the scarcity of osteohistological studies in this group. The relatively well‐preserved shell of C. placidoi (UFRPE 5600), from the Aptian age of Araripe Basin, is studied here for the purpose of filling this gap. We performed the osteohistological description of the plastron of a new specimen of C. placidoi. Also, to conduct a comparative study, we carried out histological sections in bones of the recent chelid Phrynops sp. Our histological findings indicate similarities between the histological pattern of freshwater turtles and the coastal marine C. placidoi. Moreover, osteohistological features imply metaplastic incorporation of dermal interwoven structural fiber bundles. Lastly, the xiphiplastron of C. placidoi shows an increase of bone compactness over its craniocaudal axis...
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.