Postcranial skeletal anatomy of the holotype and referred specimens of Buitreraptor gonzalezorum Makovicky, Apesteguía and Agnolín 2005 (Theropoda, Dromaeosauridae), from the Late Cretaceous of Patagonia

PeerJ

article

Federico A. Gianechini¹  Peter J. Makovicky²  Sebastián Apesteguía³  Ignacio Cerda⁴ 

[1] Instituto Multidisciplinario de Investigaciones Biológicas ,(IMIBIO-SL), CONICET—Universidad Nacional de San Luis;Section of Earth Sciences, Integrative Research Center;CONICET, Fundación de Historia Natural ‘Félix de Azara’, CEBBAD, Universidad Maimónides;CONICET, Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro

关键词: Patagonia;    Late Cretaceous;    Paraves;    Dromaeosauridae;    Unenlagiinae;    Osteology;    Paleohistology;    Buitreraptor gonzalezorum;   

DOI  :  10.7717/peerj.4558

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Here we provide a detailed description of the postcranial skeleton of the holotype and referred specimens of Buitreraptor gonzalezorum. This taxon was recovered as an unenlagiine dromaeosaurid in several recent phylogenetic studies and is the best represented Gondwanan dromaeosaurid discovered to date. It was preliminarily described in a brief article, but a detailed account of its osteology is emerging in recent works. The holotype is the most complete specimen yet found, so an exhaustive description of it provides much valuable anatomical information. The holotype and referred specimens preserve the axial skeleton, pectoral and pelvic girdles, and both fore- and hindlimbs. Diagnostic postcranial characters of this taxon include: anterior cervical centra exceeding the posterior limit of neural arch; eighth and ninth cervical vertebral centra with lateroventral tubercles; pneumatic foramina only in anteriormost dorsals; middle and posterior caudal centra with a complex of shallow ridges on lateral surfaces; pneumatic furcula with two pneumatic foramina on the ventral surface; scapular blade transversely expanded at mid-length; well-projected flexor process on distal end of the humerus; dorsal rim of the ilium laterally everted; and concave dorsal rim of the postacetabular iliac blade. A paleohistological study of limb bones shows that the holotype represents an earlier ontogenetic stage than one of the referred specimens (MPCA 238), which correlates with the fusion of the last sacral vertebra to the rest of the sacrum in MPCA 238. A revised phylogenetic analysis recovered Buitreraptor as an unenlagiine dromaeosaurid, in agreement with previous works. The phylogenetic implications of the unenlagiine synapomorphies and other characters, such as the specialized pedal digit II and the distal ginglymus on metatarsal II, are discussed within the evolutionary framework of Paraves.

【 授权许可】

CC BY