Postcranial anatomy of Prestosuchus chiniquensis (Archosauria: Loricata) from the Triassic of Brazil

Abstract

Prestosuchus chiniquensis is the best represented pseudosuchian archosaur from the Pinheiros‐Chiniquá Sequence, Middle‐Late Triassic (Ladinian/Carnian) of the Santa Maria Supersequence, Southern Brazil. Several incomplete specimens attributed to this species have been described, but the morphology of the postcranial skeleton of P. chiniquensis is poorly known. In this contribution we present the postcranial material of the UFRGS‐PV‐0629‐T specimen, concluding its description, as its skull and endocast have already been described. Additionally, histological data provided new information on the poorly known ontogenetic series of P. chiniquensis, and on its growth patterns suggesting a longer period of slow growth when compared to other basal Loricata species. A phylogenetic analysis placed UFRGS‐PV‐0629‐T in a group composed by the lectotype, paralectotype, and other described P. chiniquensis specimens, further corroborating our taxonomic hypothesis, that specimens of basal Loricata collected in Brazil are closely related to each other. Due to the association of characters found in the phylogenetic analysis, the specimen UFRGS‐PV‐0629‐T is attributed as the most complete material ever found for P. chiniquensis. As such, it is clear that the material presented here provides important new information on P. chiniquensis. Based on the results presented here, we revised the diagnosis for P. chiniquensis. However, it also evidences the need for new discoveries and studies of other specimens seeking to understand this and other closely related species, which were important components of worldwide trophic webs of the Triassic biotas.

Reassessment of the enigmatic “Prestosuchus” loricatus (Archosauria: Pseudosuchia) from the Middle‐Late Triassic of southern Brazil

“…Following Nesbitt, Zawiskie, and Dawley (2020), we a priori excluded the following terminal taxa: Archosaurus rossicus, Lewisuchus admixtus, and Pseudolagosuchus majori (combined into Lewisuchus, following Ezcurra, Nesbitt, Fiorelli, & Desojo, 2020), P. loricatus paralectotype, P. chiniquensis lectotype, and P. chiniquensis paralectotype, as the latter two were combined in the OTU Prestosuchus type series. We furthermore excluded the OTU with all specimens of Prestosuchus combined in the P. chiniquensis ALL terminal taxon (sensu Nesbitt, Zawiskie, & Dawley, 2020), and preferred analyzing this taxon with different specimens referred to this species as separate OTUs, as in Desojo et al (2020) and Mastrantonio et al (2024). Thus, the dataset evaluated the phylogenetic position of "Prestosuchus" loricatus within a framework of 96 OTUs.…”

“…We furthermore included the new iliac character proposed by Rezende et al (2022) and, based on own observations and the literature, we added 14 new postcranial characters and modified four characters of the original list of Nesbitt, Zawiskie, & Dawley, (2020). In addition, we added a further, rather complete specimen of Prestosuchus, UFRGS PV 0629 T, recently described by Mastrantonio et al (2013Mastrantonio et al ( , 2019Mastrantonio et al ( , 2024 as an additional operational taxonomic unit (OTU). The primary dataset initially included 103 OTUs, scored for 454 osteological characters (Data S1).…”

“…Epiphophysis that do not project more posteriorly than the postzygapophyses are also present in some pseudosuchians, such as the aetosauromorph Revueltosaurus, the Poposauroidea Xilousuchus, and on the atlantal neural arch of Effigia (Nesbitt, 2007(Nesbitt, , 2011. The elongated prezygapophysis and postzygapophyses resemble those of Xilousuchus and Effigia, and contrast with the shorter structures in Rauisuchus tirandentes (Lautenschlager & Rauhut, 2015), Prestosuchus chiniquensis (Mastrantonio et al, 2024), Batrachotomus kupferzellensis (SMNS 80233), and Mambawakale ruhuhu (Butler et al, 2022).…”

“…taxon over the years, starting with a large, complete skull and partial vertebral column described by Barberena in 1978, and due to the different referred specimens (e.g., Lacerda et al, 2016;Mastrantonio et al, 2013Mastrantonio et al, , 2019Mastrantonio et al, , 2024Raugust, 2014;Rezende et al, 2022;Roberto-da-Silva et al, 2018; see also Desojo et al, 2020), Prestosuchus chiniquensus is by now one of the best known non-crocodylomorph pseudosuchians. Barberena (1978) and Kuhn (1961Kuhn ( , 1976 furthermore independently designated this species as the type species of the genus Prestosuchus (but see Kischlat, 2023).…”