Tortoises and turtles from Huayquerías del Este (late Miocene–early Pliocene), Mendoza, Argentina

DE LA FUENTE, M.; ROMANO MUÑOZ, C. O.; GONZÁLEZ RUIZ P.; ALBERTO C. GARRIDO; FORASIEPI, A.M.; JANELLO, J.M.; MANIEL I.J.

The Anatomical Record

Wiley

Año: 2022 p. 1 - 29

1932-8494

We report new occurrences of Testudinidae and Chelidae from 11 different fossilsites in the Huayquerías and Tunuyan formations (late Miocene-Pliocene)in the Huayquerías del Este, Mendoza, Argentina. A total of 36 specimenswere collected, representing at least three taxa from two different clades: 80.6%Testudinidae and 19.4% Chelidae. Testudinids are present throughout thestratigraphic succession, in alluvial, fluvial, and interdune sedimentary environments,represented by dorsal and plastron carapace plates, with someremains of the appendicular skeleton. A complete articulated plastron withsome peripheral plates of the carapace was also recognized and is assigned tothe extant species Chelonoidis chilensis, representing the oldest record for thistaxon (late Miocene, Messinian). Another possible morphotype was recognizedin the form of a large scapular girdle and femur that likely corresponded to anindividual with a dorsal carapace of about 80 cm. This assemblage of smalland large tortoise species is recognized for first time in the MessinianAge/Stage of Mendoza. Chelids are mostly restricted to fluvial deposits in theupper part of the Huayquerías Formation, except for two specimens whichappear in the lower part. One specimen is represented by a right half plastronof an indeterminate Chelidae species which could correspond to a carapace ofup to 24 cm in length with plastral lobes narrower than those observed inPhrynops species. Another specimen is characterized by a large costovertebraltunnel in the carapace, peripheral plates of the posterior margin of the carapacewith ornamentation of fine grooves forming irregular polygons.