A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)

• DOI: 10.7717/peerj.857
• Publication Date: 2015-04-07T07:02:42Z
• Authors: Emanuel Tschopp; Octávio Mateus; Roger B.J. Benson
• Keywords: Cladogram; Sauropoda; Phylogenetic nomenclature; Morphological Analysis; Taxonomic rank

Diplodocidae are among the best known sauropod dinosaurs. Several species were described in late 1800s or early 1900s from Morrison Formation of North America. Since then, numerous additional specimens recovered USA, Tanzania, Portugal, and Argentina, as well possibly Spain, England, Georgia, Zimbabwe, Asia. To date, clade includes about 12 to 15 nominal species, some them with questionable taxonomic status (e.g., ‘Diplodocus’ hayi Dyslocosaurus polyonychius), ranging age Late Jurassic Early Cretaceous. However, intrageneric relationships iconic, multi-species genera Apatosaurus Diplodocus still poorly known. The way resolve this issue is a specimen-based phylogenetic analysis, which has been previously implemented for Apatosaurus, but here performed first time entire Diplodocidae.The analysis 81 operational units, 49 belong Diplodocidae. set OTUs all name-bearing type proposed Diplodocidae, alongside relatively complete referred specimens, increase amount anatomically overlapping material. Non-diplodocid outgroups selected test affinities potential diplodocid that have subsequently suggested outside clade. scored 477 morphological characters, representing one most extensive analyses Character states figured tables given case numerical characters.The resulting cladogram recovers classical arrangement relationships. Two approaches used reproducibility our delimitation genera. This resulted proposal included well-known like generically distinct. Of particular note famous genus Brontosaurus considered valid by quantitative approach. Furthermore, “Diplodocus” represents unique genus, will herein be called Galeamopus gen. nov. On other hand, these imply synonymization “Dinheirosaurus” Portugal Supersaurus. Our use specimen-, rather than species-based approach increases knowledge intraspecific variation diplodocids, study demonstrates how valuable tool taxonomy, potentially paleontology taxonomy whole.