[D] Othnielia rex [T]
Jurassic Late Kimmeridgian Tithonian
Ornithischia Ornithopoda Hypsilophodontidae
Morrison Formation, Colorado, Utah, Wyoming, US
Othnielia (Galton, 1977) > Othnielia rex (Marsh, 1877) = Nanosaurus rex (Marsh, 1877) >> Laosaurus gracilis (Marsh, 1878)
2 partial skeletons, postcranial elements, teeth.
Brill and Carrpeter (2001) desribed a baby ornithopod (DMNH 21716) which they refer to Othnielia rex The specimen was discovered by Mike Williams in the earlt to middle 1990\\\'s, in five maroob sanstone blocks, preserved in part and counterpart slabs, in the Late Jurassic, Morrison Formation of Garden Park, Colorado, nicknamed \\\"Mike\\\'s baby\\\".
The skeleton includes a femur, humerus, partial tibia and fibula, (articulated) five caudal cervical, at least five anterior dorsal, and four sacral vertebrae, caudal vertebrae, two phalanges, several ribs and paired fromtals with a postorbital of semingly a single individual. Comparison with YPM 1882, (an adult O. rex) made the authors deduced that DMNH 21716 was about one-third the length of the former, or about 750 mm.
Laosaurus consors (Marsh,1894) closely resembles Hypsilophodon in the structure of the postcranial skeleton (Galton and Jensen, 1973; as Nanosaurus rex but little about its skull is presently known. It differs from Hypsilophodon in the greater depth of the cleft between the greater and lesser trochanters of the femur and in the more proximal position of the obturator process on the ischium.