A new basal sauropod from the pre-Toarcian Jurassic of South Africa: evidence of niche-partitioning at the sauropodomorph─sauropod boundary?

摘要: The early evolution of sauropod dinosaurs remains poorly understood, with a paucity unequivocal taxa known from the first twenty million years Jurassic. Recently, Early Jurassic South Africa has yielded an assemblage dental and post-cranial displaying more apomorphic character suite than any other similarly aged sauropodomorph. These are interpreted as new species basal recovered cladistically sister taxon to Vulcanodon +more derived Sauropoda, underscoring its importance for our understanding this pivotal period evolution. Key changes in dentition, axial skeleton forelimb suggest genuine functional distinction occurring at sauropodiform-sauropod boundary. With reference these changes, we propose scenario which interdependent refinements locomotory feeding apparatus occurred tandem with, or were effected by, restrictions amount vertical forage initially available earliest sauropods. hypothesized instance niche-partitioning between sauropodan higher-browsing non-sauropodan sauropodomorphs may partially explain rarity true sauropods rocks Jurassic, while having added corollary couching origins Sauropoda terms ecologically delimited ‘event’.