| Trigonosaurus | |
|---|---|
.png) | |
| Vertebrae of theholotype (MCT 1488-R) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | †Sauropodomorpha |
| Clade: | †Sauropoda |
| Clade: | †Macronaria |
| Clade: | †Titanosauria |
| Family: | †Saltasauridae |
| Subfamily: | †Saltasaurinae |
| Genus: | †Trigonosaurus Camposet al.2005[1] |
| Species: | †T. pricei |
| Binomial name | |
| †Trigonosaurus pricei Camposet al. 2005[1] | |
Trigonosaurus (meaning "triangle lizard" afterTriangulo Mineiro, where it was found[1]), is agenus ofsaltasauriddinosaurs from theMaastrichtianSerra da Galga Formation ofBrazil. Thetype species,Trigonosaurus pricei, was first described by Campos,Kellner, Bertini, and Santucci in 2005. It was based on two specimens, both consisting mainly ofvertebrae. The two specimens were originally believed to have come from the same individual. However, one specimen was described as the holotype ofCaieiria in 2022, while the holotype may have instead come fromBaurutitan.[2] Before its description, it was known as the "Peirópolis titanosaur", after the place it was found.[1]
From the 1940s to 1960s, Brazilian paleontologistLlewellyn Ivor Price excavated several series of titanosaur fossils in the "Caieira" locality of the Serra da Galga Formation inMinas Gerais, Brazil. Two of these, "Series B" or MCT 1488-R and "Series C" or MCT 1490-R, were named the holotypes of two titanosaur genera in 2005:Trigonosaurus andBaurutitan respectively.[1] The describers ofTrigonosaurus also referred a series of caudal vertebrae, MCT 1719-R, as the paratype of their new genus.[1] Further titanosaur fossils from the BR-262 site of the same locality were reported by Silva Junior and colleagues in 2022, and in light of this new evidence, reconsidered MCT 1488-R to be a specimen ofBaurutitan, thus synonymizingTrigonosaurus with it. They also separated the caudal vertebrae (paratype) fromTrigonosaurus and described it as the holotype of a new genus and species of titanosaur,Caieiria allocaudata.[2] However, not all researchers have accepted the conclusion thatTrigonosaurus is a synonym ofBaurutitan; John Fronimos, in 2023, did not follow the proposed synonymy due to the differencess between the first caudal vertebrae of the two taxa.[3]
