Abstract
The side-necked turtle genusBairdemys (Podocnemididae,Shweboemys Group) from the Miocene of Venezuela and Puerto Rico is revised, and four species are diagnosed on the basis of skull characters; two are de-scribed as new.B. hartsteini Gaffney & Wood, 2002, from the Cibao Formation of Puerto Rico, is characterized by a higher skull, with a straight labial ridge and a premaxillary notch;B. venezuelensis (Wood & Díaz de Gamero 1971), from the Urumaco Formation of Venezuela, is characterized by the absence of a premaxillary notch, a high anterior triturating surface convexity, a deep posterior triturating surface concavity, and a short pterygoid mid-line contact;B. sanchezi, new species, from the Urumaco Formation of Venezuela, is characterized by a very low anterior triturating surface convexity and shallow posterior triturating surface concavity, a premaxillary notch, small size, and extensive temporal and cheek emargination;B. winklerae, new species, from the Urumaco Formation of Venezuela, is characterized by an elongate, narrow snout, with a concave labial ridge, and no premaxillary notch. Based on osteological and bone histological results, an additional strongly crushed skull and associated cara-pace fragment of a previously undetermined podocnemidid from the Urumaco Formation of Venezuela can be further referred toPodocnemis or a closely related taxon — again underscoring the importance of this formation as one of the major fossil lagerstätten of turtles in South America.
Zusammenfassung
Die Halswenderschildkröten der GattungBairdemys (Podocnemididae,Shweboemys-Gruppe) aus dem Miozän von Venezuela und Puerto Rico werden revidiert. Aufgrund von diagnostischen Schädelmerkmalen werden vier Arten unterschieden, inklusive zwei hierin neu beschriebener Arten.B. hartsteini Gaffney & Wood, 2002, aus der Cibao Formation, Puerto Rico, ist durch einen hohen Schädel, eine gerade Labialkante des Prämaxillare und eine Prämaxillarkerbe gekennzeichnet,B. venezuelensis (Wood & Diaz de Gamero 1971) aus der Urumaco-Formation Venezuelas durch das Fehlen einer Prämaxillarkerbe, eine hohe anteriore Konvexität und eine tiefe posteriore Konkavität der Kauflächen und einen kurzen Mittellinienkontakt der Pterygoide. Die hier neu beschriebeneB. sanchezi n. sp. aus der Urumaco-Formation, Venezuela, ist charakterisiert durch eine sehr niedrige anteriore Konvexität und eine flache posteriore Konkavität der Kauflächen, eine geringe Größe und starke Temporal- und Wangeneinbuchtungen, wogegenB. winklerae n. sp. aus der Urumaco Formation, Venezuela, durch eine verlängerte schmale Schnauze mit einer konkaven Labialkante charakterisiert ist. Durch osteologische und knochenhistologische Befunde lassen sich ein weiterer stark verdrückter Schädel sowie ein assoziiertes Panzerfragment einer bisher unbestimmten Podocnemidide der GattungPodocnemis oder deren unmittelbarer Verwandtschaft zuordnen. Dies unterstreicht wiederum die Bedeutung der Urumaco-Formation als eine der wichtigsten Lagerstätten fossiler Schildkröten in Südamerika.
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Gaffney, E.S., Scheyer, T.M., Johnson, K.G. et al. Two new species of the side necked turtle genus,Bairdemys (Pleurodira, Podocnemididae), from the Miocene of Venezuela. Paläont. Z. 82, 209–229 (2008). https://doi.org/10.1007/BF02988411
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DOI: https://doi.org/10.1007/BF02988411