A small abelisaurid caudal vertebra from the Bauru Basin, Presidente Prudente Formation (Late Cretaceous), Brazil adds information about the diversity and distribution of theropods in central South America.

Abelisauridae is a diverse clade of theropod dinosaurs, geographically well-distributed especially in the southern continents during the Cretaceous. The record of abelisaurids in South America comes mainly from Patagonia, whereas in Brazil they are mostly represented by numerous dental crowns and isolated bones, with few formally named species, mostly coming from the Late Cretaceous beds of the Bauru Group. In this contribution, we describe a small abelisaurid mid-caudal vertebra (LPRP/USP L0020) from the Presidente Prudente Formation, Bauru Group. LPRP/USP L0020 bears several abelisaurid features, such as an almost flat ventral surface, a poorly constrict centrum, lack of pneumatization, and distally positioned transverse processes. Body length estimation suggest that LPRP/USP L0020 belonged to a roughly 3.4 m long adult animal, representing one of the smallest known abelisaurids. The discovery of LPRP/USP L0020 indicates that Late Cretaceous abelisaurids from central South America were more diverse in body size than previously known, and possibly as diverse as their Patagonian counterparts. • Abelisauridae are the main group of theropods found in the Bauru Basin, Late Cretaceous, Brazil. • A new vertebra of Abelisauridae (LPRP/USP L0020) is described from Osvaldo Cruz, São Paulo, Presidente Prudente Formation. • LPRP/USP L0020 is regarded belonging to a small size Abelisauridae. • LPRP/USP L0020 suggests that abelisaurids were highly diverse in central South America during the Late Cretaceous. [ABSTRACT FROM AUTHOR]