A new species of Tenontosaurus (Dinosauria: Ornithopoda) from the Early Cretaceous of Texas

ABSTRACT

Two articulated skeletons of an ornithopod dinosaur from the Early Cretaceous of Texas form the basis for description of a new species of Tenontosaurus. The new ornithopod, Tenontosaurus dossi sp. nov., is a sister species to Tenontosaurus tilletti Ostrom found in Montana and Wyoming. Specimens of the new species are temporally older than those of T. tilletti, and in most cases of unequivocal polarity they are more primitive. The Texas species is clearly the most primitive iguanodontian, and thus shares many primitive characters with the weakly supported clade Hypsilophodontidae. The specimens from Texas represent unscavenged carcasses entombed in a brackish-water lagoonal or estuarine sands.