New lizard record (Diapsida, Lepidosauria) from the Upper Cretaceous Adamantina Formation, Brazil

Abstract

A new record of a Late Cretaceous lizard-like non-serpentian squamate from Adamantina Formation (Bauru Group; Turonian-Santonian) southeast of Brazil is based on a specimen found about 10 km south of Marília city (São Paulo State). The material consists of 10 articulated dorsal vertebrae with a total length of 14 mm and seven incomplete right ribs. Vertebrae are gracile, procoelous, with a broad intervertebral foramen, without evidence of intercentra, and with a single synapophysis; ribs are unicapitate. The specimen is assigned to the Squamata because of the presence of procoelous vertebrae, absence of intercentra in the dorsal vertebrae, and the presence of slender and elongate single-headed ribs. In addition, the material is excluded from the Serpentes owing to the absence of separated diapophyses and parapophyses, the lack of clearly triangular centra in ventral view, presence of anteroposterior short and well posteriorly-inclined neural spines, and, if it is present, the weakly developed zygosphene-zygantrum articular complex. Despite retaining an open taxonomic identification, the material represents the first non-serpentian squamate from the Adamantina Formation, enlarging the record of squamates in the Bauru Group of Brazil, and indicates the presence of minute lizard taxa, which are sparse in the South American Cretaceous fossil record.