Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids.
Tyrannosauroids are one of the last and the most successful large-bodied predatory dinosaur groups, but their early history remains poorly understood. Here we report a new basal tyrannosauroid from the Early Cretaceous Yixian Formation of western Liaoning, China, which is small and gracile and has relatively long arms with three-fingered hands. The new taxon is the earliest known unquestionable tyrannosauroid found so far. It shows a mosaic of characters, including a derived cranial structure resembling that of derived tyrannosauroids and a primitive postcranial skeleton similar to basal coelurosaurians. One of the specimens also preserves a filamentous integumentary covering similar to that of other coelurosaurian theropods from western Liaoning. This provides the first direct fossil evidence that tyrannosauroids had protofeathers.
Xu
Xing
X
Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China. xu@amnh.org
Norell
Mark A
MA
Kuang
Xuewen
X
Wang
Xiaolin
X
Zhao
Qi
Q
Jia
Chengkai
C
D000818:Animals; D002681:China; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000145:classification*; D005241:Feathers / Q000033:anatomy & histology*; D005580:Fossils; D034582:Integumentary System / Q000033:anatomy & histology; D012863:Skeleton; D012886:Skull / Q000033:anatomy & histology