Achillesaurus

Achillesaurus is named after the Greek hero Achilles, because its ankle bones were fused together like Achilles' famous tendon.2

It lived about 85 to 83 million years ago during the Santonian stage of the Late Cretaceous.1

Achillesaurus was a relatively large alvarezsaurid, bigger than its close relative Alvarezsaurus.2

Its fossils were found in the Bajo de la Carpa Formation in Argentina, which was a dry, sandy environment.52

Unlike some Asian alvarezsaurids, Achillesaurus did not have a highly reduced fibula or a special foot structure called arctometatarsalian.2

Scientists are not sure exactly where Achillesaurus fits in the alvarezsaur family tree, because it shares features with both South American and Asian species.2