A probable baryonychine (Theropoda: Spinosauridae) tooth from the Upper Cretaceous of Henan Province, China
David W. E. HONE, XU Xing, WANG De-you
Abstract A single large theropod tooth was recovered from the middle Upper Cretaceous Majiacun Formation, Henan Province, China. The morphology of the tooth strongly suggests that it belongs to a baryonychine spinosaurid theropod based on the following features: long, conical tooth with a sub-circular cross-section, slight recurvature along the length of the tooth and numerous fine denticles on both anterior and posterior carinae. This tooth therefore may represent the first record of the baryonychines in Asia, and the first in the Late Cretaceous. This suggests that the baryonychines were more widely distributed both geographically and temporally than previously thought. Based on the gross morphology and inferred ecology of spinosaurids as a whole, we note that these animals are surprisingly rare in the fossil record compared to other theropod clades. This suggests that in life they may have been genuinely rare animals, perhaps as a result of their extreme morphological specialisation.
Key words Asia, theropod, dinosaur, spinosaurid, ecology