Achillobator (Matt Martyniuk).


Achillobator (combination Greek/Mongolian for "Achilles warrior"); pronounced ah-KILL-oh-bate-ore


Plains of central Asia

Historical Period:

Late Cretaceous (95-85 million years ago)

Size and Weight:

About 20 feet long and 500-1,000 pounds



Distinguishing Characteristics:

Large size; huge claws on feet; odd alignment of hips


About Achillobator

As far as paleontologists can tell, Achillobator (the name, "Achilles warrior," refers both to this dinosaur's large size and to the large Achilles tendons it must have had in its feet) was a raptor, and thus in the same family as Deinonychus and Velociraptor.

However, Achillobator does appear to have possessed some quirky anatomical features (mainly concerning the alignment of its hips) that differentiated it from its more famous cousins, which has led some experts to speculate that it may represent an entirely new type of dinosaur. (One other possibility is that Achillobator is a "chimera": that is, it was reconstructed from the remains of two unrelated dinosaur genera that happened to be buried in the same location.)

Like other raptors of the Cretaceous period, Achillobator is often depicted as sporting a coat of feathers, underlining its close evolutionary relationship with modern birds. However, this is based not any solid fossil evidence, but the presumed featheriness of small theropod dinosaurs at some stage during their life cycles. In any case, at up to 20 feet long from head to tail and 500 to 1,000 pounds, Achillobator was one of the largest raptors of the Mesozoic Era, exceeded only in size by the truly gigantic Utahraptor (which lived halfway around the world, in early Cretaceous North America) and making the much smaller Velociraptor seem like a chicken by comparison.