NEW PTEROSAUR TEETH FROM THE LOHAN CURA FORMATION (LOWER CRETACEOUS) OF SOUTHERN NEUQUÉN BASIN (PATAGONIA, ARGENTINA) WITH A PROPOSAL OF AN IDENTIFICATION METHOD FOR ISOLATED ANHANGUERIAN TOOTH SPECIMENS

CIAFFI, A.; BELLARDINI, F.; SARDELLA, R.

Salta

Jornada; Reunion de Comunicaciones de la Asociacion Paleontologica Argentina; 2022

APA IBIGEO IEBI UNSA IBIGEOP

The pterosaur fossil record of Argentina is sparse, consisting mainly of isolated and fragmentaryremains and few well preserved specimens, spanning from the Upper Triassic to the UpperCretaceous. In this contribution we report twenty isolated pterosaur teeth stored in the MuseoMunicipal “Carmen Funes” of Plaza Huincul (MCF-PVPH-739-2, 741, 743, 875, 879-1 to 879-11,880-1 to 880-5) from the Cerro de los Leones locality (Picún Leufú, Neuquén Province), where theLohan Cura Formation (Albian) widely outcrops. This unit yielded an abundant and diversifiedfossil record, composed of sauropod and theropod dinosaurs, turtles, crocodiles, fresh-watermollusks and plants; however, the pterosaur specimens are scarce and represented by few isolatedteeth and a well-preserved ulna fragment, which we identified as indeterminate members of thepterodactyloid clade Anhangueria. The cross section and curvature of the teeth suggest they couldbelong to various clades of fish and reptiles, including pterosaurs. Where preserved, however, theenamel and dentine layers show patterns with ridges and wrinkles unique to anhanguerianpterosaurs. The number of specimens allowed a more in-depth morphological analysis and thecategorization in highly inclusive morphotypes, which suggest a different anatomical position insideof the jaw. Indeed, anhanguerian pterosaurs show heteromorphic dentition, in which three maintooth shapes can be discerned: morphotype 1, more labio-lingually curved than mesio-distally andwith subcircular cross section, typical of rostral teeth; morphotype 2, more labio-lingually curvedthan mesio-distally, with suboval cross section and carinae, corresponding to the middle tooth-row;a morphotype 3, more curved mesio-distally than labio-lingually, which characterizes the posteriorteeth. Therefore, we consider the MCF-PVPH-879-4, 879-6, 879-8, 879-10 teeth of Cerro de losLeones of morphotype 1 as rostral teeth of indeterminate anhanguerians, MCF-PVPH-739-2, 743,879-9, 880-1 to 880-5 of morphotype 2 as middle anhanguerian tooth-row, and MCF-PVPH-741,875, 879-1, 879-2, 879-3, 879-5, 879-7, 879-11 of morphotype 3 as posterior anhanguerian teeth.The tooth morphological classification here proposed represents a new methodology to identifyisolated anhanguerian teeth, as well as to explore the paleoecological and paleontologicalimplications related to the pterosaur feeding evolution and diversification. Moreover, the evidenceof anhanguerian pterosaurs in the Cerro de los Leones has paleobiogeographical implications,allowing us to correlate this Albian record with others of South America and Gondwana, expandingour understanding of the paleobiogeography of Lower Cretaceous pterosaurs from southwesternGondwana