Podocnemidinae Cope, 1868

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 : 21-22

Subfamily Podocnemidinae Cope, 1868

NEW DIAGNOSIS: Members of the Podocnemididae ; quadratojugal-parietal contact long; foramen jugulare posterius closed; tuberculum basioccipitale widely spaced; crista supraoccipitalis with horizontal plate on ventral edge (except in Erymnochelys and Peltocephalus ); cervical centra saddle shaped (except in Erymnochelys and Turkanemys , which have a third state).

INCLUDED TAXA: Podocnemis Wagler, 1830 ; Peltocephalus Duméril and Bibron, 1835 ; Erymnochelys Baur, 1888 ; Bairdemys Gaffney and Wood, 2002 ; Dacquemys Williams, 1954c ; Neochelys Bergounioux, 1954 ; Shweboemys Swinton, 1939 ; Stereogenys Andrews, 1901 ; Caninemys Meylan, Gaffney, and Campos, 2009 ; Turkanemys Wood, 2003 ; Neochelys Bergounioux, 1954 ; Papoulemys Tong, 1998 ; Peiropemys , n. gen.; Lapparentemys , n. gen.; Pricemys , n. gen.; Mogharemys , n. gen.; Cordichelys , n. gen.; Latentemys , n. gen.; Brontochelys , n. gen.; Albertwoodemys , n. gen.; Lemurchelys , n. gen.

DISCUSSION: Two subfamilies of the Podocnemididae have been named by Broin (1988 [1989]) the ‘‘subfamily Podocnemidinae’’ and the ‘‘subfamily Erymnochelinae .’’ Although used in a number of additional papers ( Broin, 1991; Lapparent de Broin, 2000b, 2001, 2003a, 2003b), the most complete expression of the hypothesis is Lapparent de Broin (2000b).

The ‘‘subfamily Podocnemidinae’’ was considered by Lapparent de Broin (2000b) as containing Podocnemis , Peltocephalus , Bauruemys , ‘‘aff. Roxochelys vilavilensis ’’ (5 Lapparentemys ), and Stupendemys . This group of Lapparent de Broin (2000b) was not confirmed in our analysis. Besides the successive sister-group relationship of ( Bauruemys ( Lapparentemys ( Podocnemis ))), we have found a number of characters linking Peltocephalus with the taxon below, Lapparent de Broin’s ‘‘ Erymnochelyinae .’’ In our analysis, the ‘‘subfamily Podocnemidinae’’ of Lapparent de Broin (2000b) is simply the South American podocnemidids. The character that seems to be dominant in Lapparent de Broin (2000b, and other papers) for this taxon is the saddle-shaped cervicals, but biogeography may have been an influential phylogenetic character. There is a series of shell characters as well, but the distributions are not clear. Apparently, the fact that Bauruemys lacks the cervical character was not yet known and the author used the shell features and geography to place this species in this group.

The ‘‘subfamily Erymnochelinae’’ was considered by Lapparent de Broin (2000b) as containing Erymnochelys , Neochelys , Stereogenys , Shweboemys , Dacquemys , and ‘‘Carteremys’’ (the last genus a nomen dubium in Gaffney et al., 2006). This group is essentially the present authors’ magnatribe Erymnochelydand. The reflection of the cladogram in the classification requires its change in rank from Lapparent de Broin (2000b), but we agree in most of its content and its principal character. The primary character used for this group ( Lapparent de Broin, 2000b: 70) is the ‘‘Much eroded roof of the enlarged carotid canal, the prootic and quadrate being so much eroded that the floor of the canalis cavernosus is broken and this canal is anteriorly confluent with the part of ‘enlarged canal’ leading to the sulcus cavernosus (not known in Dacquemys , homoplastic but with a less eroded roof in the podocnemidine Peltocephalus ).’’ The interesting fact that the character does actually occur in a member of Lapparent de Broin (2000b) ’s other subfamily (i.e., Peltocephalus ) is recognized by Lapparent de Broin (2000b), but the geographic distribution was perhaps a more important consideration. There are now a few cervicals showing that extinct members of Lapparent de Broin’s ‘‘Erymnochelyinae’’ did have saddle-shaped centra.

When analyzing only the Recent genera, none of the molecular results reproduce the Lapparent de Broin (2000b) resolution of ( Erymnochelys ( Podocnemis , Peltocephalus )); rather they prefer the ( Peltocephalus ( Podocnemis , Erymnochelys )) arrangement, while the present paper agrees with neither and finds the ( Podocnemis ( Peltocephalus , Erymnochelys )) resolution to be most attractive (see Phylogenetic Analysis).

Gaffney and Meylan (1988) used ‘‘ Podocnemidinae Williams, 1954 (as ‘podocnemides’)’’ as an equivalent to what we now call the family Podocnemididae . In the present paper we redefine the subfamily Podocnemidinae to be the monophyletic group consisting of all Podocnemididae except Bauruemys .