New Itasuchidae (Sebecia, Ziphosuchia) remains and the radiation of an elusive Mesoeucrocodylia clade

Crocodyliformes have a well-known worldwilde fossil record, revealing a high diversity of morphological traits, habits and being abundant in their paleofaunas. Such abundance in the fossil record is remarkable in the tetrapod fossil record in the continental sequences of Bauru Group (Brazil), in the Cretaceous of the South America. Here we describe and analyse three specimens from Bauru Group, assigned to a poorly understood crocodyliform clade: Itasuchidae. Their morphological similarity assigned them as Pepesuchus (from Turonian / Coniacian of Aracatuba Formation), Itasuchus cf. jesuinoi, and cf. Roxochampsa paulistanus (both last from Campanian to Early Maastrichtian of Presidente Prudente Formation). The phylogenetic and morphometric results corroborated the monophyly of the Itasuchidae with some variation in its content regard to prior and similar analyses (i.e. inclusion of Stolokrosuchus, Barreirosuchus and Antaeusuchus; exclusion of Caririsuchus), also pointing out to the South American itasuchid species as occupying a crocodyliform morphospace, which can imply distinct niche occupations. The Bauru Group undergoes a diversity peak of archosaurs in Upper Cretaceous, with a remarkable Crocodyliformes radiation, such as the Itasuchidae group, which probably have their most early-diverging lineages rising from Lower Cretaceous of Africa.

Automated summary

Crocodyliformes from the Bauru Group in Brazil, including specimens of Itasuchidae, have been analysed and described. The morphological analysis revealed the similarity between these specimens and the species of Pepesuchus, Itasuchus cf. jesuinoi, and cf. Roxochampsa paulistanus. The phylogenetic and morphometric results confirmed the monophyly of Itasuchidae and suggested that South American itasuchid species occupied a distinctive morphospace among crocodyliforms. The Bauru Group represents a diversity peak of archosaurs in the Upper Cretaceous. Rating: 8/10.