Podocnemis unfilis (Troscehl 1848; 45cm long) is the extant yellow-spotted river turtle. Females can be twice the size of males. This side-neck turtle (= Pleurodira) nests basal to all other texted side-neck turtles.

Pelomedusa subrufa (extant, Lacépède 1788, Boycott and Bourquin 2008; 20 cm carapace length) is the African helmeted turtle. Skull shown at left.

Foxemys skull at right.

Foxemys mechinorum (above right; Tong et al. 1998) is an extinct genus of side-necked turtle (Pleurodira) with a tiny head and huge low carapace.

Sahonachelys mailakavava (Joyce et al. 2021; Late Cretaceous) is a pelomedusoid turtle from Madagascar that nests basal to long-necked Chelus and Arapemys in the LRT. It was considered a suction feeder based on an estimate 53% neck-carapace ratio. Some bones here are reidentified based on a demonstrated pareiasaur ancestry. The most conspicuous characteristic of this clade is the presence of an extended posterior process of the maxilla. Here the prefrontal is still visible on either side of the nasal.

Boycott RC and Bourquin O 2008. Pelomedusa subrufa (Lacepede 1788) helmeted turtle, helmeted terrapin. Conversation biology of freshwater turtles and tortoises: A compilation project of the IUCN/SSC tortoise and freshwater turtle specialist group. Chelonian Research Foundation. pdf

Gaffney ES 1979. Comparative cranial morphology of recent and fossil turtles. Bulletin of the American Museum of Natural History 164(2):65-376.

Joyce WG et al. 2021. A new pelomedusoid turtle, Sahonachelys mailakavava, from the Late Cretaceous of Madagascar provides evidence for convergent evolution of specialized suction feeding among pleurodires. Royal Society. Open Scence. 8: 210098.
https://doi.org/10.1098/rsos.210098

Lacépède BGe de 1788. Histoire Naturelle des Quadrupèdes Ovipares et des Serpens. Tome Premier. Paris: Hôtel de Thou, 651 pp. Quarto edition

Tong H, Gaffney ES; Buffetaut E 1998. Foxemys, a new side-necked turtle (Bothremydidae, Pelomedusoides) from the late Cretaceous of France. American Museum Novitates 3251:1–19.

Troschel H 1848. Amphibien, pp. 645-661 in Schomburgk R (ed), Versuch einer Zusammenstellung der Fauna and Flora von Britisch-Guiana. Leipzig.

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