Monday 8 July 2013

A new species of Ankylosaurid Dinosaur from the Late Cretaceous of Montana.

The Ankylosaurids were large armored Dinosaurs from the Cretaceous of Europe, Asia and North America. Their bodies were encased in heavy armor forming an effective shell and they had large bony clubs on the ends of their tails. They are believed to have been entirely herbivorous, and had beak-like mouths, occasionally with residual teeth.

In a preliminary paper published on the journal Acta Palaeontologica Polonica's website on 4 February 2013, Paul Penkalski of The Geology Museum in Madison Wisconsin describes a new species of Ankylosaurid from the Late Cretaceous Two Medicine Formation of northern Montana.

The new Dinosaur is named Oohkotokia horneri, where 'Oohkotokia' means 'child of stone' in latinized Blackfoot and 'horneri' honours Jack Horner, a distinguished palaeontologist and expert on the Dinosaurs of Montana. The species is described from two partial skulls, a partial pelvis, some forelimb and hindlimb elements and an osteoderm (bony plate formed within the skin).

Skull of Oohkotokia horneri in dorsal view with interpretive drawing. Penkalski (2013).

Skull of Oohkotokia horneri in ventral (A₁) and lateral (A₃) views with interpretive drawings (A₂ & A₄). Scale bar is 10 cm. Penkalski (2013).

Postcranial material of Oohkotokia horneri. (A) Partial cervical vertebra; well-preserved fourth or fifth free caudal in (B) distal and (C) left lateral view; (D) lateral plate in two views; (E) conical osteoderm; (F) oval, low-keeled osteoderm in external view; (G) partial scapula; (H) stereo pair of two osteoderms; (I) opposite (=cranial) view of conical osteoderm shown in (H); (J) ribbed subconical osteoderm. Scale bar is 10 cm. Penkalski (2013).

Sacrum (or sacra) associated with Oohkotokia horneri. (A) Presacral rod(?) in ventral view; (B) dorsosacral(?) centra in dorsal (left) and ventral views; (C) posterior sacrals with reattached ?s3 rib in ventral view; (D–F) sacral ribs in cranial view; (G) fused neural arches in ventral and dorsal views; (H) nodosaurid sacral fragment. Scale bars in centimeters. Penkalski (2013).

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