Sauropia: Difference between revisions – Wikipedia

 

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== References ==

== References ==

Genus of procolophonoid reptiles

Sauropia is an extinct genus of procolophonoid sauropsid known from the Middle Triassic Santa Maria Formation of Brazil. The genus contains a single species, Sauropia macrorhinus, known from a very small skull and mandible. It may belong to the family Procolophonidae, but the immature nature of the only known specimen makes this identity uncertain.^[1]

The Sauropia fossil material was discovered at the ‘Cortado site’, representing outcrops of the Santa Maria Formation, (Pinheiros-Chiniquá Sequence, Santa Maria Supersequence) in Novo Cabrais of Rio Grande do Sul, Brazil. This locality is part of the Dinodontosaurus Assemblage Zone (AZ). The specimen is housed in the Centro de Apoio à Pesquisa Paleontológica, part of the Federal University of Santa Maria, where it is permanently accessioned as specimen CAPPA/UFSM 0510. The specimen consists of nearly all of a skull, articulated with the mandible.^[1]

In 2026, Rodrigo T. Müller and colleagues described Sauropia macrorhinus as a new genus and species of procolophonoid ‘parareptile‘ based on these fossil remains, establishing CAPPA/UFSM 0510 as the holotype specimen. The generic name, Sauropia, combines the Ancient Greek σαῦρος (sauros), meaning ‘lizard‘, with the Portuguese word piá, referring to a child or young boy. This word is particularly prevalent in Gaúcho culture in the region where the holotype was found, and was chosen in reference to the likely early ontogenetic stage and especially small size of this specimen. The specific name, macrorhinus, combines the Greek word makros, meaning ‘large‘, and rhinos, meaning ‘snout‘/‘nose‘, alluding to the large external nares seen in the known skull.^[1]

The holotype skull of S. macrorhinus is 9.5 millimetres (0.37 in) long. The skull is almost as wide as it is long, with a maximum width at the temporal region of 8.7 mm (0.34 in). As such, it is the smallest tetrapod skull known from the Middle Triassic of South America.^[1]

Like many fossils from the Dinodontosaurus AZ, much of the specimen is covered in mineral concretions, with the external bone surface poorly preserved. As such, much of the anatomy and details of CAPPA/UFSM 0510 are obscured. This is exacerbated by the specimen’s tiny size. When seen from above, the snout of the specimen is broad and rounded. This region comprises a comparatively short and deep part of the skull. These proportions are more similar to some procolophonids than owenettids (the two major lineages of Procolophonoidea), as the latter are characterized by a longer, flatter snout. The external nares (‘nostril hole‘ in the skull) are especially wide and tall. When seen from the side, the external naris is elongated, similar to owenettids and basal procolophonoids. The orbitotemporal fenestra (‘eye hole‘ in the skull) is similarly elongate, with the rear margin almost reaching the posterior part of the skull. In owenettids, this fenestra is anteroposteriorly shorter (shorter from front to back). There are three tooth positions in the premaxilla, similar to some procolophonids and in contrast to owenettids, which have at least five. These teeth in Sauropia are straight, cylindrical in cross-section, and lacking cusps. The front tip of the premaxilla projects downward. The maxilla is incomplete, missing the rear portion. The number of maxillary teeth is unclear, as only one tooth is preserved in the right maxilla. The bones of the skull roof are poorly preserved and difficult to distinguish, but it likely had particularly wide frontals, a distinctive feature not seen in other procolophonoids (possibly due to the individual’s young age). The mandible is generally horseshoe-shaped. Its dentition is not visible.^[1]

To assess the relationships of Sauropia within the Procolophonoidea, Müller and colleagues included it in an updated version of the phylogenetic matrix of Mueller et al. (2023).^[2] This analysis placed Sauropia within the family Procolophonidae, in a large uresolved polytomy with several other early-diverging taxa, one of which, Oryporan, is also from the Triassic of Brazil.^[3] These results are displayed in the cladogram below:^[1]