Open AccessPostcranial osteology of Beipiaosaurus inexpectus (Theropoda: Therizinosauria)
Author(s) -
Chenghong Liao,
Lindsay E. Zanno,
Shiying Wang,
Xing Xu
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0257913
Subject(s) - postcrania , osteology , holotype , anatomy , autapomorphy , taxon , yixian formation , biology , theropoda , paleontology , geology , zoology , taxonomy (biology) , phylogenetics , biochemistry , mesozoic , structural basin , gene
Beipiaosaurus inexpectus , from the Lower Cretaceous Yixian Formation (Sihetun locality, near Beipiao), Liaoning, China, is a key taxon for understanding the early evolution of therizinosaurians. Since initial publication in 1999, only the cranial elements of this taxon have been described in detail. Here we present a detailed description of the postcranial skeletal anatomy of the holotype specimen of B . inexpectus , including two never before described dorsal vertebrae from the anterior half of the series. Based on these observations, and comparisons with the postcranial skeleton of therizinosaurian taxa named since the most recent diagnosis, we revised the diagnostic features for B . inexpectus adding three new possible autapomorphies (PII-3 shorter than PIII-4, subequal length of the pre- and postacetabular portions of the ilium, and equidimensional pubic peduncle of ilium). Additionally, we also propose three possible synapomorphies for more inclusive taxa (Therizinosauroidea and Therizinosauridae) and discuss implications for evolutionary trends within Therizinosauria. The newly acquired data from the postcranial osteology of the holotype specimen of B . inexpectus sheds light on our understanding of postcranial skeletal evolution and identification of therizinosaurians.