A possible brachiosaurid (Dinosauria, Sauropoda) from the mid-Cretaceous of northeastern China

Abstract

Brachiosauridae is a lineage of titanosauriform sauropods that includes some of the most iconic non-avian dinosaurs. Undisputed brachiosaurid fossils are known from the Late Jurassic through the Early Cretaceous of North America, Africa, and Europe, but proposed occurrences outside this range have proven controversial. Despite occasional suggestions that brachiosaurids dispersed into Asia, to date no fossils have provided convincing evidence for a pan-Laurasian distribution for the clade, and the failure to discover brachiosaurid fossils in the well-sampled sauropod-bearing horizons of the Early Cretaceous of Asia has been taken to evidence their genuine absence from the continent. Here we report on an isolated sauropod maxilla from the middle Cretaceous (Albian–Cenomanian) Longjing Formation of the Yanji basin of northeast China. Although the specimen preserves limited morphological information, it exhibits axially twisted dentition, a shared derived trait otherwise known only in brachiosaurids. Referral of the specimen to the Brachiosauridae receives support from phylogenetic analysis under both equal and implied weights parsimony, providing the most convincing evidence to date that brachiosaurids dispersed into Asia at some point in their evolutionary history. Inclusion in our phylogenetic analyses of an isolated sauropod dentary from the same site, for which an association with the maxilla is possible but uncertain, does not substantively alter these results. We consider several paleobiogeographic scenarios that could account for the occurrence of a middle Cretaceous Asian brachiosaurid, including dispersal from either North America or Europe during the Early Cretaceous. The identification of a brachiosaurid in the Longshan fauna, and the paleobiogeographic histories that could account for its presence there, are hypotheses that can be tested with continued study and excavation of fossils from the Longjing Formation.

Sauropod dinosaur teeth from the lower Upper Cretaceous Winton Formation of Queensland, Australia and the global record of early titanosauriforms

“…The slightly younger (late Albian) Chinese titanosauriform Borealosaurus preserves a single tooth that is too worn for meaningful comparison [416]. The Albian-Cenomanian Longjing Formation has recently produced twisted teeth evincing the presence of a brachiosaurid, possibly implying mid-Cretaceous sauropod interchange between North America and Asia [417]. Many narrow-crowned teeth (SI often greater than 5.0) attributed to titanosaurs have been recovered in Uzbekistan from uppermost Albian/lower Cenomanian deposits, as well as the middle-upper Turonian Bissekty Formation [93,418,419].…”

New macronarian from the Middle Jurassic of Chongqing, China: phylogenetic and biogeographic implications for neosauropod dinosaur evolution

“…[78,107], and this study). Besides them, phylogenetic analyses support the Middle Jurassic African sauropod Atlasaurus as a ‘basal’-most member of either Diplodocoidea or macronarian (see also: [80,108,109]), whereas some previous studies have recovered it outside of Neosauropoda [110,111]. Ferganasaurus , from the Callovian Balabansai Formation of Kyrgyzstan, was described as a neosauropod [112], but subsequent analysis suggests it was positioned outside the Neosauropoda clade [113].…”