La Buitrera lizards: Unexpected diversity for the early Late Cretaceous of Argentina

APESTEGUÍA, SEBASTIÁN; GARBEROGLIO, FERNANDO FABIO; GÓMEZ, RAÚL ORENCIO; CALDWELL, MICHAEL WAYNE; NYDAM, RANDALL; SIMÕES, TIAGO R.; KALUZA, JONATAN

Cordoba

Jornada; XXIII Jornadas Argentina de Paleontología de Vertebrados; 2019

Asociación Paleontológica Argentina

Lizards have been present in South America since Gondwanan or perhaps Pangeantimes. However, earliest records belong, up to now, to the Early Cretaceous of the CratoFormation. Though originally considered as basal squamatans, new studies considerthem as belonging to different groups of scincomorphs (i.e., Polyglyphanodontinae,basal forms close to Cordyliformes) and stem acrodonts (uromastycines). The recordfrom Argentina includes an isolated scincomorph jaw from the Campanian AnacletoFormation and a frontal from the Cenomanian Candeleros Formation. Here we presentthe first comparative results of a sustained collection of lizard remains in the La BuitreraPaleontological Area (Candeleros Formation). The remains are represented by threeisolated frontals, including a new one which is three times larger than the published one;a fragment of toothed lower jaw; an incomplete postcranium (including dorsal vertebraeand pelvis with attached femora) of a large or moderately large individual; and, acomplete skull and a partial postcranium (cervical and anterior dorsal vertebrae plus partof the pectoral girdle) of a very small individual. Concerning their affinities, thepublished frontal was assigned to ?iguanids?, the fragment of jaw shows scincomorphteeth, and the small complete skull shows a different morphology of bones anddentition, indicating the presence of another clade. Although lizards at La Buitreraremain in a not overlapping adaptative zone respect to that occupied byrhynchocephalians and crocodyliforms, they are still diverse in size, shape and in thelineages represented.