Neochelys Bergounioux, 1954

Gaffney, Eugene S., Meylan, Peter A., Wood, Roger C., Simons, Elwyn & De Almeida Campos, Diogenes, 2011, Evolution Of The Side-Necked Turtles: The Family Podocnemididae, Bulletin of the American Museum of Natural History 2011 (350), pp. 1-237 : 41-42

Neochelys Bergounioux, 1954

SYNONYMY: See Broin (1977), Lapparent de Broin (2003a).

TYPE SPECIES: Emys capelinii de Zigno, 1889 .

INCLUDED SPECIES: Neochelys arenarum , N. fajumensis , N. franzeni , N. capellinii , N. eocenica , N. zamorensis . See Broin (1977), Schleich (1993), and Lapparent de Broin (2003a) for more information on species.

DISTRIBUTION: Eocene, Europe, northern Africa. A possible podocnemidid record of a Neochelys -like epiplastron was reported by Hutchison et al. (2004). Although the epiplastron is very similar to some Neochelys we do not feel this is sufficient for a range extension to Southeast Asia. The epiplastron may not be a pleurodire.

DIAGNOSIS: A podocnemidid known from the skull and postcrania; skull relatively high and narrow in contrast to Bauruemys ; orbits facing dorsolaterally; interorbital groove such as found in Podocnemis absent (except as a variation); temporal emargination less than in Podocnemis ; parietal-quadratojugal contact long; cheek emargination slight; postorbital large in contrast to Podocnemis ; medial expansion of triturating surface, median maxillary ridge, present; accessory ridge or ridges absent in triturating surface; vomer absent; fossa precolumellaris shallow as in Podocnemis expansa in contrast to deep as in Erymnochelys ; foramen jugulare posterius closed; interparietal scale equilateral triangle; cavum pterygoidei with large anterior opening and foramen cavernosum in roof; horizontal occipital shelf absent; chorda tympani enclosed in processus retroarticularis.

Postcrania with nuchal bone width greater than length; neural series variable with six or seven neurals extending to meet costals six and seven; first neural is four sided; axillary buttress reaches peripheral three; pectoral scales do and do not contact mesoplastra, but do contact entoplastron and epiplastra.

DISCUSSION: A number of species have been named for this genus, Broin (1977), Schleich (1993), and Lapparent de Broin (2003a) attempt to diagnose and clarify these. Only Neochelys arenarum Broin has had its skull described (except for the basisphenoid of Neochelys cf. arenarum, Lapparent de Broin, 2003a ), although Lapparent de Broin (2003a: table 1) compares cranial features among Neochelys arenarum and some undescribed specimens.

Although the species are a problem, the genus is well diagnosed by a unique combination of characters. It possesses a wide parietal-pterygoid contact, as in the tribe Stereogenyini that is absent or narrow in Podocnemis , and absent in Erymnochelys and Peltocephalus . Neochelys has a relatively small interparietal scale that is an equilateral triangle, as in Papoulemys and some Podocnemis , but absent in Erymnochelys , Peltocephalus , and the tribe Stereogenyini . Neochelys and Papoulemys also lack accessory ridges in a group, the infrafamily Podocnemidodda , characterized by them.

Lapparent de Broin (2000a: 68; 2001: 171) questionably suggested the presence of Neochelys in the Fayum Eocene as ‘‘Genus indet. ( Neochelys group?: ‘ Stereogenys ’) podocnemoides Reinach, 1903 : Qasr El Sagha beds, Fayum, Egypt Late Eocene’’ ( Lapparent de Broin, 2000a: 68). Although there has not been further discussion of this suggestion, the known material of podocnemoides includes a plastron with a large intergular scale that divides the gulars, intergulars, and reaches the pectoral scales (Reinach, 1903: pl. 10, fig. 1), in contrast to the material identified in this paper as fajumensis (fig. 47), which has a small intergular not dividing these scales. Whether or not podocnemoides Reinach, 1903 , belongs to Neochelys or another genus is indeterminable.