R is for Rapetosaurus

One sauropod deserves another. After briefly profiling the as-yet-little-known Qiaowanlong last week, it’s only natural to follow up with Rapetosaurus krausei – another recently-named Mesozoic herbivore that altered our understanding of the forms some sauropod lineages took.

Paleontologists Kristina Curry Rogers and Catherine Forster named Rapetosaurus in 2001. As the researchers dubbed the dinosaur in the paper’s title, the sauropod was among “the last of the dinosaur titans.” At somewhere between 66 and 70 million years old, Rapetosaurus roamed Madagascar during what we can look back at and call the waning days of the Cretaceous. And the record of this dinosaur is particularly rich among its kind – scattered remains of multiple individuals, including articulated specimens, have been found within a ten square kilometers of Madagascar’s Cretaceous exposures.

Among the various sauropod lineages, Curry Rogers and Forster concluded, Rapetosaurus belonged to the titanosaur branch. This widespread group of long-necked leaf-munchers included some of the largest dinosaurs of all time, including the 100 foot plus Argentinosaurus, although adult Rapetosaurus stretched a more modest 50 feet or so. And unlike other titanosaurs, Rapetosaurus had a peculiar skull that superficially resembled those of diplodocid dinosaurs such as Apatosaurus and Diplodocus itself.

In a 2004 follow-up focused on the head of Rapetosaurus, Curry Rogers and Forster drew from two partial skulls to fill out the dinosaur’s anatomy and compare the sauropod to other titanosaurs. While closely-related dinosaur had relatively deep, stocky skulls, Rapetosaurus had a longer, more slender cranium with the nasal opening up between the eyes. Not all titanosaurs followed the same anatomical rules. Given the number of titanosaurs paleontologists have named, and how few skulls have been found, there may have been even more skeletal diversity than we presently understand. Despite being some of the largest and most impressive dinosaurs, titanosaurs are still prehistoric enigmas.

Previous entries in the Dinosaur Alphabet series:

Q is for Qiaowanlong

P is for Pelecanimimus

O is for Ojoceratops

N is for Nqwebasaurus

M is for Montanoceratops

L is for Leaellynasaura

K is for Kileskus

J is for Juravenator

A-I at Dinosaur Tracking.

References:

Curry Rogers, K., Forster, C. 2001. The last of the dinosaur titans: a new sauropod from Madagascar. Nature. 412: 530-534

Curry Rogers, K., Forster, C. 2004. The skull of Rapetosaurus krausei (Sauropoda: Titanosauria) form the Late Cretaceous of MadagascarThe skull of Rapetosaurus krausei (Sauropoda: Titanosauria) form the Late Cretaceous of MadagascarThe skull of Rapetosaurus krausei (Sauropoda: Titanosauria) form the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology. 24, 1: 121-144

Curry Rogers, K. 2009. The postcranial osteology of Rapetosaurus krausei (Sauropoda: Titanosauria) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology. 29, 4: 1046-1086