FIRST ICHNOLOGICAL EVIDENCE OF A SWIMMING TETRAPOD IN THE CRATO MEMBER OF SANTANA FORMATION (ARARIPE BASIN, NORTHEASTERN BRAZIL)

FIRST ICHNOLOGICAL EVIDENCE OF A SWIMMING TETRAPOD IN THE CRATO MEMBER OF SANTANA FORMATION (ARARIPE BASIN, NORTHEASTERN BRAZIL). The so-called Ipubi layers (Aptian/Albian) of the Crato Member of Santana Formation (Araripe Basin, NE Brazil) are composed by a series of discontinuous evaporite packages interbedded by black and green shales. An unusual isolated footprint preserved in a block of black shale ex situ from the Ipubi layers (Mina Pedra Branca, Nova Olinda, Ceara) is described herein. The footprint has 36.7 mm wide and 21.26 mm long and the track have five parallel scratch marks that describe a curve to the left. The mark corresponding to the died I begins with a thin and short claw mark, while those attributed to digits II, III and IV begin with a rounded claw mark. The mark produced by digit V is the shortest. The marks at the beginning of the footprint are much deeper and thicker than the end. The morphology of these marks suggest they were produced by the autopodium of a tetrapod animal while swimming near the bottom and are consistent with the anatomical features of the manus of a turtle. The preservation of this unusual footprint increases the fossil record of the Santana Formation and opens a new research line to the Araripe Basin.