Blair W Mcphee & Jonah N Choiniere (2017)
The osteology of Pulanesaura eocollum: implications for the inclusivity of Sauropoda (Dinosauria).
Zoological Journal of the Linnean Society, zlx074 (advance online publication)
We present the complete osteology of the putative basal sauropod Pulanesaura eocollum. Current phylogenetic hypotheses suggest that Pulanesaura is the sister taxon of Vulcanodon + other sauropods, a position supported primarily by derived features of its axial skeleton and forelimb. A question of nontrivial importance is therefore the relative position of Pulanesaura with respect to current higher taxonomic groupings within Sauropodomorpha. The most recently proposed cladistic definition of Sauropoda (the most inclusive clade not including Melanorosaurus) places Pulanesaura as an unambiguous sauropod, whereas another commonly cited definition (the least inclusive clade containing Vulcanodon and Saltasaurus) suggests it is the most proximate sauropod outgroup. In addition to the issues pertaining to the validity of Melanorosaurus, we highlight a suite of features that can be shown to unambiguously and exclusively co-occur at the base of Sauropoda sensu the latter definition, arguing in favour of its continued use. As a corollary to this interpretation, we suggest that, instead of being simple diagnostic artefacts, (complex) apomorphies remain valid signifiers of notable phylogenetic loci whose contribution to our current classificatory schemes remains underexploited.