basal titanosaurian found to date, Triunfosaurus was initially used to support the hypothesis that the wider group originated on the supercontinent Gondwana around the Hauterivian, more specifically within South America. Nevertheless, an alternate hypothesis involving dispersal out of Europe remains plausible. Reassignment as an indeterminate somphospondylan In a subsequent redescription of the somphospondylan Austrosaurus, Steven Poropat and colleagues raised a number of objections to the titanosaurian status of Triunfosaurus. Poropat et al. noted that the furrow separating the arch into two surfaces, used by Carvalho et al. to assign Triunfosaurus to the Titanosauria, is likewise present in the non-titanosaur somphospondylans Phuwiangosaurus and Tangvayosaurus. They remarked that the short haemal canal directly contradicts the Titanosauria as defined by Wilson in 2002, although this feature is somewhat variable. Additionally, the assignment of the caudal vertebrae to the middle of the tail was also questioned by Poropat et al.. Features in these vertebrae that are unusual for middle caudal vertebrae include the prominent transverse processes bearing deep diapophyses (articulations with the ribs), the pronounced prezygodiapophyseal laminae connecting the prezygapophyses and transverse processes, the well-developed spinoprezygapophyseal laminae connecting the prezygapophyses and neural spines, the deep indentations on the outer margins of the bottom of the centra, and the postzygapophyseal facet joints extending backwards from the midpoint of the side of the centra. The size of the transverse processes suggests that the vertebrae actually originate from the front of the tail, making their association with the ischium questionable due to their overall small size. For these reasons, Poropat et al. reassigned Triunfosaurus to the Somphospondyli, being unable to confidently support its titanosaurian affinities due to its problematic nature. Paleoecology Vertebrate fossils from the Triunfo Basin tend to be extremely fragmentary. From the Poço County locality, fragments of crocodylomorph bones have been found. The Triunfo Basin is better known for presence of ichnotaxa; more than 535 individual trackways produced by dinosaurs are known from the basin. Some of these footprints may have been made by Triunfosaurus. The environment probably consisted of alluvial fans and systems of rivers. See also 2017 in archosaur paleontology References External links Image of the fossil finds Titanosaurs Early Cretaceous dinosaurs of South America Cretaceous Brazil Fossils of Brazil Fossil taxa described in 2017