First pterosaur tracks from Brazil

Abstract

We describe here the first record of pterosaur fossil tracks from the Lower Cretaceous of Brazil, based on new records from the Botucatu Formation (Paraná Basin). These rocks comprise a desert region of dunes and interdunes from which several tetrapod tracks/trackways are known, including tridactyl dinosaurs, lizards and small mammals; giving some clues about the inhabitants of this ancient desert. The new findings were recovered from the well-known Ouro ichnosite (Araraquara Municipality, São Paulo State), and are represented by isolated and well-preserved tridactyl tracks, with left manus (LPP-IC-0232) being digitigrade and the left pes (LPP-IC-0233) being plantigrade. The manus imprint is asymmetrical with a long impression of digit III pointing backwards; these features distinguish this track from tridactyl dinosaurs, resembling a rhombic track morphology, diagnostic of Pteraichnus. Furthermore, in the pes imprint, the metatarsal region is about four times longer than the digital region. Three short, anteriorly directed digit impressions are present, in addition to the midfoot arch (pedal isthmus) on the medial edge of track, which are also features of Pteraichnus. This is the first occurrence of pterosaur tracks in Brazil, classified as Pteraichnus isp., increasing the ichnological diversity of the Botucatu Formation and also of the Brazilian geopaleontological heritage.