Arrudatitan

''Arrudatitan'' (meaning " Arruda's giant") is an extinct genus of titanosaur sauropod dinosaur known from the Late Cretaceous (Campanian-Maastrichtian)-aged Adamantina Formation of Brazil. The type species, ''A. maximus'', was named and described in 2011 as a species of ''Aeolosaurus'', but was separated into its own genus in 2021. It was relatively gracile for a titanosaur.

Discovery and naming

The holotype, MPMA 12-0001-97, which includes two partial posterior cervicals, fragments of several dorsals, parts of nine caudals, seven partial cervical ribs, twelve partial dorsal ribs, eight chevrons, a fragmentary scapula and arm bones, the left and partial right femur, the left ischium, and fragments; with other specimens known, such as the isolated middle caudal vertebra MPP 248, was discovered in 1997 by Ademir Frare and his 12-year-old nephew Luiz Augusto dos Santos Frare in a field in Cândido Rodrigues. They notified palaeontologist Antônio Celso de Arruda Campos and the holotype was collected between 1997 and 1998 by staff of the Museu de Paleontologia de Monte Alto and it was first mentioned in scientific literature by Santucci and Bertini (2001). They noted that crocodylomorph and theropod teeth were found near the holotype, but no bite marks were present. In 2009, Fernando Novas briefly noted on the holotype, noting its size.

MPMA 12-0001-97 was initially assigned to ''Aeolosaurus'' in 2011, when the species ''Aeolosaurus maximus'' was created by Santucci & De Arruda-Campos. As early as Martinelli ''et al.'' (2011), published shortly before ''Aeolosaurus maximus'' was described, the caudal vertebra of the holotype of ''Aeolosaurus maximus'' was seen as an indeterminate aeolosaurin distinct from ''Aeolosaurus'', with Bandeira ''et al.'' (2016) referring to the species as "''A''"''. maximus'' throughout their paper describing the titanosaurian sauropod '' Austroposeidon magnificus'' due to ''Aeolosaurus maximus'' being sufficiently different from ''Aeolosaurus'' but had not yet been placed within a different genus; and subsequent analyses, such as Silva ''et al.'' (2019) and Hechenleitner ''et al.'' (2020), found that ''Aeolosaurus maximus'' did not belong in the ''Aeolosaurus'' genus and so the new genus ''Arrudatitan'' was erected in 2021 by Silva ''et al.''.

Description

''Arrudatitan'' grew up to when fully grown, based on the size of the holotype. Novas, F. E. (2009). ''The Age of Dinosaurs in South America''. Indiana University Press, Bloomington and Indianapolis, Indiana. The femur length of ''Arrudatitan'' is .

Classification

The species ''Aeolosaurus maximus'' was named by Santucci and De Arruda-Campos in 2011 for titanosaur remains recovered in the Adamantina Formation of Brazil. However, subsequent cladistic analyses, such as those by Silva ''et al.'' in 2019 and Hechenleitner ''et al.'' in 2020 have considered ''A. maximus'' to be outside ''Aeolosaurus'', the former analysis finding it to be sister to Rinconsauria and the latter finding it to be closely related to a clade consisting of '' Punatitan'' and the other two ''Aeolosaurus'' species. In light of this, Silva ''et al.'' transferred it to the new genus ''Arrudatitan'', after Brazilian paleontologist Antonio Celso de Arruda Campos.

A cladogram of the phylogenetic analysis performed by Silva ''et al.'', 2021 is shown below:

References

{{Taxonbar, from=Q22104075

Titanosauria
Dinosaur genera
Maastrichtian dinosaurs
Adamantina Formation
Dinosaurs of Brazil
Fossil taxa described in 2021