[D] Linheraptor exquisitus [sG] [T]
Xu, Choiniere, Pittman, Tan, Q., Xiao, Li, Tan, L., Clarck, Norell, Hone & Sullivan 2010
Cretaceous Late Campanian
Saurischia Theropoda Tetanurae Coelurosauria Dromaeosauridae
Wulansuhai Formation, Bayan Madahu, “The Gate” locality, China
A dromaeosaurid theropod from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia. Linheraptor exquisitus gen. et sp. nov., is based on an exceptionally well-preserved, nearly complete skeleton. This specimen represents the fifth dromaeosaurid taxon recovered from the Upper Cretaceous Djadokhta Formation and its laterally equivalent strata, which include the Wulansuhai Formation, and adds to the known diversity of Late Cretaceous dromaeosaurids.
Linheraptor exquisitus closely resembles the recently reported Tsaagan mangas. Uniquely among dromaeosaurids, the two taxa share a large, anteriorly located maxillary fenestra and a contact between the jugal and the squamosal that excludes the postorbital from the infratemporal fenestra. These features suggest a sister-taxon relationship between L. exquisitus and T. mangas , which indicates the presence of a unique dromaeosaurid lineage in the Late Cretaceous of Asia. A number of cranial and dental features seen in L. exquisitus and T. mangas, and particularly some postcranial features of L. exquisitus, suggest that these two taxa are probably intermediate in systematic position between known basal and derived dromaeosaurids. The discovery of Linheraptor exquisitus is thus important for understanding the evolution of some salient features seen in the derived dromaeosaurids.
IVPP V 16923, an articulated, nearly complete skeleton.
The generic name refers to the animal’s status as a predatory dinosaur (‘raptor’) from Linhe, Nei Mongol, China (area of origin); the specific name refers to the exceptional preservation of the holotype specimen.
Locality and Horizon
Bayan Mandahu, “The Gate” locality, Wulansuhai Formation, Campanian, Upper Cretaceous (Jerzykiewicz et al. 1993).
Dromaeosaurid that can be distinguished from other known dromaeosaurid taxa by the presence of the following autapomorphies: greatly enlarged maxillary fenestra sub-equal in size to external naris; several large foramina on lateral surface of jugal. Differs from other known dromaeosaurids except Tsaagan in the following features: large and anteriorly located maxillary fenestra; lacrimal lacking lateral flange over descending process and with relatively broad medial lamina; sharp angle between anterior and ascending processes of quadratojugal; contact between jugal and squamosal that excludes postorbital from infratemporal fenestra.
Differs from Tsaagan in the following features: absence of osseous inner wall partly blocking antorbital fenestra; sharply rimmed ventral margin of antorbital fossa; considerably smaller angle between frontal and jugal processes of postorbital; anteroventrally curved postorbital process of squamosal; considerably shorter quadratojugal process of squamosal; dorsoventrally shorter lateral flange of quadrate; less curved and less posteriorly inclined quadrate shaft; paroccipital process more laterally oriented; angular more extended posteriorly towards glenoid fossa; considerably deeper posterior end of mandible such that glenoid fossa is approximately level with tooth row; pneumatic foramen present on axis vertebra.