Sunday 9 June 2013

A new species of Ceratopsid Dinosaur from the Late Cretaceous of southern Alberta.

Ceratopsid Dinosaurs were a speciose group of large, herbivorous Dinosaurs from the Late Cretaceous of Asia and North America. They were large, quadruped Dinosaurs with distinctive neck-frills and horns, and many vertebrate paleaontologists have speculated that the large number of species may have been the result of sexual selection, as in many modern Mammals. The group do not show any great ecological diversity, but each species has a distinctive arrangement of horns and frill-ornaments; if this is a result of sexual selection it is likely that the males and females of many species have been described separately.

In a paper published in the Canadian Journal of Earth Science on 23 November 2013, Michael Ryan of the Department of Vertebrate Paleontology at Cleveland Museum of Natural History, David Evans of the Department of Natural History at the Royal Ontario Museum and the Department of Ecology and Evolutionary Biology at the University of Toronto, and Kieran Shepherd of Earth Sciences at the Canadian Museum of Nature, describe a new species of Ceratopsid Dinosaur from the Late Cretaceous of southern Alberta.

The new species is named Xenoceratops foremostensis, meaning 'The Alien Ceratopsid from the Foremost Formation'; it is the first Ceratopsid ever found in the Foremost Formation, as well as being (by a small margin) the oldest Ceratopsid ever found in Canada. Xenoceratops foremostensis is described from fragmentary material from at least three individuals, all of which is derived from the skull; the post cranial anatomy of the species is unknown.

Material from the first specimen of Xenoceratops foremostensis. (A) Right P2 process. (B–D) Partial midline, left posterior, and lateral ramus: (B) posterior (ventral surface up, specimen rotated around the long axis of the P3 spike); (C) dorsal; and (D) ventral views. (E, F) Anteriormost left lateral ramus with contact for squamosal: (E) dorsal and (F) ventral views. P#, parietal process No.; PF, parietal fenestra; EP, epiparietal. Scale bar 5 cm. Ryan et al. (2012).

Material from the second specimen of Xenoceratops foremostensis. (A) Posterior, (B) dorsal, and (C) ventral views; (D) close-up of open suture for P3. P#, parietal process No.; P# sut, epiparietal sutural surface. Scale bar 10 cm. Ryan et al. (2012).

Material from the third specimen of Xenoceratops foremostensis. (A) Dorsal and (B) ventral views. P#, parietal process No. Scale bar 10 cm. Ryan et al. (2012).

Reconstructions of Centrosaurinae parietals. (A) Xenoceratops foremostensis; (B) Centrosaurus apertus; (C) Styracosaurus albertensis; (D) Achelousaurus horneri; (E) Albertaceratops nesmoi; (F) Pachyrhinosaurus lakustai; (G) Einiosaurus procurvicornus(H) Diabloceratops eatoniRyan et al. (2012).

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