Abstract
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.
Highlights
Therizinosaurus were a rare and bizarre clade of maniraptoran dinosaurs
Skeletal remains have been discovered from Cretaceous strata of Asia and North America [4,5,6,7,8], Eshanosaurus deguchiianus from the Lufeng Formation, Yunnan, China might represent an Early Jurassic therizinosaurian [9, 10]
A detailed description of the postcranial skeleton of the specimen is needed to further understand this important taxon. We present such a description of the postcranial skeletal osteology of the holotype specimen (IVPP V11559) in order to fill in new anatomical information on this key taxon and shed light on the evolution of the postcranial skeleton within Therizinosauria
Summary
Therizinosaurus were a rare and bizarre clade of maniraptoran dinosaurs. Late-branching taxa possessed characteristic features such as a rostrally endentulous snout, dentary with a lateral shelf, small tightly packed lanceolate teeth, diminutive skulls, elongate neck, extremely broad and opisthopubic pelvis, shortened tibia, and tetradactyl pes [1,2,3]. Skeletal remains have been discovered from Cretaceous strata of Asia and North America [4,5,6,7,8], Eshanosaurus deguchiianus from the Lufeng Formation, Yunnan, China might represent an Early Jurassic therizinosaurian [9, 10]. Beipiaosaurus inexpectus is an early-branching therizinosaurian from the Lower Cretaceous Yixian Formation in Liaoning, China.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
