Abelisauridae was first defined by Novas (1997) and Sereno (1998) as a node-based taxon. Wilson et al. (2003) presented a second-order revision of Abelisauridae as a stem-based taxon in opposition to the stem-based taxon Noasauridae, which came to be recognized as its sister taxon. The advantage of a stem-based definition of Abeliauridae is that it forms a stable node-stem triplet, identifying a major dichotomy in the history of the Abelisauroidea. As a node-based taxon, in contrast, Abelisauridae would have excluded the recently described basal member Rugops (Sereno et al. 2004). Taxonomists appear to have followed this arrangement, regarding Rugops as an abelisaurid.
The active definition, thus, is a first-order revision of that stem-based definition, which uses species. The revised definition also cites for exclusion two additional species (Coelophysis bauri, Passer domesticus) that ensure stabiliy of the taxonomic content of Abelisauridae, should abelisaurids be placed elsewhere among basal theropods.
Padian (1999) and Tykoski and Rowe (2004) have followed the initial definitions of Novas (1997) and Sereno (1998). Tykoski and Rowe (2004), nonetheless, were unaware of the earlier second-order revision by Wilson et al. (2003).