The vertebrate fossil record from the Feliz Deserto Formation (Lower Cretaceous), Sergipe, NE Brazil: paleoecological, taphonomic, and paleobiogeographic implications

Abstract

The Feliz Deserto Formation (Berriasian–Valanginian, Sergipe–Alagoas Basin, NE Brazil) preserved some of the earliest South American fossil records of the rifting stages which resulted in the Gondwana supercontinent break-up during the Early Cretaceous. Recently, the first spinosaurid theropod record of this formation was described, based on a tooth recovered from Canafístula 01 locality in Sergipe State. We add herein twenty-seven isolated specimens to the fossil record of the Lower Cretaceous Feliz Deserto Formation. The new material includes seven isolated spinosaurid theropod teeth of the spinosaurine clade, as well as an indeterminate theropod preungual pedal phalanx. In addition, we describe an isolated crocodyliform osteoderm, as well as eighteen isolated teeth, some of which were taxonomically identified in three distinct morphotypes of neosuchian crocodyliforms. These findings expand the Gondwanan fossil record of both spinosaurine theropods and neosuchian crocodyliforms. Despite the fragmented nature of the specimens, these new fossils allowed the characterization of their general taphonomic features with low fluvial transport of bioclast prior to the burial. The depositional paleoenvironment of the Canafístula 01 locality is compatible with the deltaic system unit, that characterizes part of the Feliz Deserto Formation during the Early Cretaceous. These fossil findings exemplify the co-occurrence of spinosaurid dinosaurs and more than one taxon of crocodyliforms in the deltaic-lacustrine paleoenvironment represented by the Feliz Deserto Formation. These new occurrences reinforce the fossiliferous potential of the Canafístula 01 locality, especially related to the paleovertebrates from the Lower Cretaceous of Brazil.