Malawisaurus

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Malawisaurus

Malawisaurus (Malawi-sore-us) was a sauropod dinosaur that lived in what is now Malawi (Africa) during the Early Cretaceous (about 120 million years ago). It belongs to a group of sauropods called titanosaurs, which were similar to more familiar sauropods like Apatosaurus and Diplodocus, but had even smaller heads, and very long, whip-like tails. Unlike Apatosaurus and Diplodocus, which became extinct at the end of the Jurassic (about 145 million years ago), titanosaurs survived in many parts of the world until the end Cretaceous extinction event (about 66 million years ago).


Genus and Species

Classification: Sauropoda, Titanosauria

Genus: Malawisaurus, after its country of origin

Species: M. dixeyi, after F. Dixey, who collected the first bones of Malawisaurus


Characteristics

Malawisaurus is small for a sauropod, but still would have been among the largest animals in its habitat. Its small skull had very large nostrils and a blunt snout, much like the American sauropod Camarasaurus. The vertebrae in the middle portion of its tail are elongate, contributing to the great length of the tail. Like other titanosaurs (but not other groups of sauropod), Malawisaurus had bony ossicles, called osteoderms, embedded in the skin.


Size

Length: 16 meters (52 feet)

Weight: 10 tons


Behavior

Study of bonebeds (layers of rock containing the scattered bones of many individuals) and trackways (fossilized footprints) indicate that sauropods formed herds. This was almost certainly true of Malawisaurus as well. Interestingly, at least some sauropod species form herds segregated by size, with large and small animals separating to form their own herds. There is a huge difference in size between a baby and an adult sauropod, and so they had very different diets. It made sense for the large and small animals to split up and go out in search of their own meals.


History of Discovery

Malawisaurus was collected in the early part of the 20th century, and described but the famous South African paleontologist Sidney Haughton in 1928. He named it Gigantosaurus dixeyi, but the genus Gigantosaurus was later shown, for technical reasons, to be unavailable, so it was renamed Malawisaurus by Louis Jacobs and colleagues in 1993.


Paleoenvironment

Malawisaurus was a herbivore, using its long neck to move its head to its vegetarian meal. At one time, it was thought that sauropods were too big and heavy to have supported themselves on land, and so took to the water to float their great bulk. We now know that they were primarily terrestrial, but they do seem to have preferred coastal areas, and fossil footprints show that they did occasionally venture into shallow water, perhaps to access food, or even to cool off.


References

Haughton, S.H. 1928. On some reptilian remains form the Dinosaur Beds of Nyasaland. Transaction of the Royal Society of South Africa 16:67-75.
Jacobs, L.L., Winkler, D.A., Downs, W.R., and Gomani, E.M. 1993. New material of an Early Cretaceous titanosaurid sauropod dinosaur from Malawi Palaeontology 36:523-534.
Paul, Gregory S. (2010) The Princeton Field Guide to Dinosaurs.