Redescription of the dorsal vertebrae of the mamenchisaurid sauropod Xinjiangtitan shanshanesis Wu et al. 2013

Abstract

ABSTRACT The dorsal vertebrae of Xinjiangtitan shanshanesis (SSV12001) from the Late Jurassic Qigu Formation of Xinjiang Uygur Autonomous Region, China, are redescribed based on the further exposure and preparation of the holotype. As a mamenchisaurid sauropod dinosaur, Xinjiangtitan shanshanesis displays a unique combination of autapomorphic and plesiomorphic features, such as the presences of both lateral spinopostzygapophyseal laminae (L.SPOL) and medial spinopostzygapophyseal lamina (M.SPOL) in dorsal vertebrae and a shallow intralaminar fossa (SPOL-F) between the L.SPOL and M.SPOL; anterior spinodiapophyseal laminae (A.SPDL), posterior spinodiapophyseal laminae (P.SPDL) and middle spinodiapophyseal lamina (M.SPDL) in dorsals 3–5; bifurcated anterior and middle dorsal neural spines with the median tubercle and the triangular lateral processes. Phylogenetic analysis and morphological comparison show that Xinjiangtitan shanshanesis probably shares a close relationship with Hudiesaurus and Mamenchisaurus and provide new information for future taxonomic revision of the mamenchisaurids.