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

Abstract

ABSTRACT 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 Araçatuba 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.