Rapetosaurus

Rapetosaurus was a medium-sized titanosaur sauropod discovered in the Late Cretaceous Maevarano Formation of north-western Madagascar. Reaching about fifteen metres in length, it inhabited an island ecosystem subject to severe seasonal droughts. The discovery of Rapetosaurus was a landmark moment in sauropod palaeontology: an exquisitely preserved juvenile skeleton was found associated with a complete skull, resolving decades of debate by conclusively proving that slender-snouted, peg-toothed nemegtosaurids were genuine titanosaurs. In addition, osteoderms found in the quarry suggest that Rapetosaurus bore large bony armour plates along its body. These osteoderms may have served as mineral reservoirs to help survive recurrent dry seasons as well as providing protection against apex predators like the abelisaurid Majungasaurus.

Its discovery definitively proved that nemegtosaurid-type skulls belonged to titanosaurs rather than surviving diplodocoids.

Where and when

Rapetosaurus lived in the Late Cretaceous, from 70 to 66 million years ago (Maastrichtian age). Its remains come from Madagascar, in the Maevarano Formation.

The numbers

Length 15 m (estimates run from 14 to 15 m). Mass about 9.8 t. Hip height about 3 m. That is 8.5 human-lengths, or 1.29 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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