Common Language Summary
A dramatic look into the head of a unique predatory dinosaur. A combination of exceptional fossil preservation and high-tech 3D imaging allows a remarkably detailed investigation of the skull of Majungasaurus , a medium-sized theropod dinosaur collected from 68-million-year-old rocks in northwestern Madagascar. Majungasaurus was formerly known as Majungatholus . The fossil skull bones are well preserved, undistorted, and disarticulated, allowing them to be examined from all sides. Also, many of the bones were subjected to CT scanning and advanced computer visualization, which not only permitted a view of the interior structure of the bones but also allowed the reconstruction of a number of soft-tissue features, such as blood vessels, nerves, air sinuses, and aspects of brain and inner ear structure. This unusually rich source of information reveals a lot about the fleshy head of Majungasaurus and not just its bony skull . The skin of the head was thickened in areas and so tightly adhered to the underlying bone that much of the bone surface is extremely roughened (in fact, this rugosity probably reflects ossification of the deepest layers of the dermis). The bones along the top of the skull (nasal, lacrimals, frontals) are not only roughened, but also bear evidence that they may have sported ornamenting scales or hornlike structures. At the same time, these bones are basically hollow, being filled in life with large paranasal air sinuses. The brain cavity, as well as the brain within, was quite small and simple. Indeed, Majungasaurus was not a clever animal, but rather a powerful one. Its skull structure indicates large jaw muscles, a powerful bite, and a sturdy skull and neck structure, such that Majungasaurus was perhaps capable of dispatching its prey using the unusual technique of biting-and-holding (perhaps even suffocating its prey), followed by forceful extraction of large chunks of flesh.

Sampson, S. D. and L. M. Witmer. 2007. Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Memoirs of the Society of Vertebrate Paleontology 8, Journal of Vertebrate Paleontology 27(Supplement to 2):32–102.

This project was funded by grants from the National Science Foundation .