ceratopsians Sauropelta Anchiceratops ceratopsids forelimbs callitrichines titanosaurs Psocomorpha dromaeosaurids Cotylorhynchus Gorgosaurus fenestrae antechinuses artiodactyls Shelmalier Lectin Like snout lemurs chordates Thescelosaurus Microraptor beak maxilla dentition adapids Daspletosaurus ungulates Yinlong Eotyrannus Deinonychus xylothemelia rakers dromaeosaurid viperids Kentrosaurus apomorphies basal skydisk