Abstract: Creaceous Research sept. Ismar de Souza Carvalho, Leonardo dos Santos Avilla, and Leonardo Salgado 2003

A new genus and species of an Aptian–Albian sauropod from the Itapecuru Formation, northern Brazil, Amazonsaurus maranhensis, is described. It is known from an incomplete, but diagnostic postcranial skeleton. The new taxon possesses several autapomorphies, such as the anterior caudal vertebrae with lateral laminae formed by the coalescence of the spinoprezygapophyseal and postzygodiapophyseal laminae and, to a lesser extent, of the postzygodiapophyseal laminae. It exhibits many synapomorphies supporting its inclusion in the Diplodocoidea. These include high caudal neural arches and anterior caudal neural arches with spinoprezygapophyseal laminae on the lateral aspect of the neural spine.This record is consistent with previous hypotheses on the existence of a community of Afro-South American dinosaurs.

Etymology: Amazonsaurus = "For the type-locality which is part of the Brazilian Legal Amazon region, plus _sauros_, Greek for lizard, reptile." marahensis = "From the Brazilian state of Maranhao." (Carvalho et al. 2003, 699)

Holotype: MN 4558-V (dorsal neural spine), UFRJ-DG 58-R/9 (dorsal neural spine), MN 4559-V (dorsal centrum), MN s/n-V (dorsal centrum), neural spine of anterior caudal vertebra (UFRJ-DG 58-R/7), one mid caudal vertebra (MN 4555-V), one mid-posterior caudal vertebra (MN 4560-V), one posterior caudal vertebra (MN 4556-V), one posterior caudal vertebra (UFRJ-DG 58-R/10), four cehvrons (UFRJ-DG 58-R/2 through [...] 58-R/5), four more chevrons (MN 4564-V), ilium (UFRJ0-DG 58-R/1), partial pubis (MN s/n-V), and three ribs (MN 4562-V).