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The cervical vertebrae of the Late Cretaceous abelisaurid dinosaur Carnotaurus sastrei

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Mendez A. H.

Acta Palaeontologica Polonica

2014

tom 59

nr 3

The cervical vertebral series of Carnotaurus sastrei from Argentina is described in detail, and compared with Majungasaurus crenatissimus from Madagascar, both Late Cretaceous (Maastrichtian) in age. Notable differences in the morphology of the cervical vertebrae, especially in the shape and development of the epipophysis and the neural spines, are observed between these two genera. These differences show a neck much more robust in Carnotaurus than in Majungasaurus, may be linked to the evolution of the clade in relation to the divergence time since the two genera shared a common ancestor, and functionally may relate to the feeding function associated to the extreme reduction of the forelimbs.

Ontogenetic changes in the craniomandibular skeleton of the abelisaurid dinosaur Majungasaurus crenatissimus from the Late Cretaceous of Madagascar

100%

Ratsimbaholison N. O., Felice R. N., O’Connor P. M.

Acta Palaeontologica Polonica

2016

tom 61

nr 2

Abelisaurid theropods were one of the most diverse groups of predatory dinosaurs in Gondwana during the Cretaceous. The group is characterized by a tall, wide skull and robust cervical region. This morphology is thought to have facilitated specialized feeding behaviors such as prolonged contact with prey. The Late Cretaceous abelisaurid Majungasaurus crenatissimus typifies this abelisaurid cranial morphotype. Recent fossil discoveries of this species include a partial growth series that allows for the first time an investigation of ontogenetic variation in cranial morphology in a representative abelisaurid. Herein we examine growth trajectories in the shape of individual cranial bones and articulated skulls of Majungasaurus using geometric morphometrics. Several major changes in skull shape were observed through ontogeny, including an increase in the height of the jugal, postorbital, and quadratojugal, an increase in the extent of the contacts between bones, and a decrease in the circumference of the orbit. The skull transitions from relatively short in the smallest individual to tall and robust in large adults, as is seen in other theropods. Such morphological change during ontogeny would likely have resulted in different biomechanical properties and feeding behaviors between small and large individuals. These findings provide a post-hatching developmental framework for understanding the evolution of the distinctive tall skull morphology seen in abelisaurids and other large-sized theropod dinosaurs.

Ograniczanie wyników

2 Acta Palaeontologica Polonica

1 Felice R. N.

1 Mendez A. H.

1 O’Connor P. M.

1 Ratsimbaholison N. O.

1 2016

1 2014

Wyniki wyszukiwania

The cervical vertebrae of the Late Cretaceous abelisaurid dinosaur Carnotaurus sastrei

Ontogenetic changes in the craniomandibular skeleton of the abelisaurid dinosaur Majungasaurus crenatissimus from the Late Cretaceous of Madagascar