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Welcome to Achillesaurus

Name Definition

Achilles’s lizard

Name Given By

Martinelli & Vera, 2007

Location

Bajo de la Carpa Formation in Rio Negro Province, Argentina

Classification

Dinosauria, Saurischia, Theropoda, Maniraptora, Alvarezsauridae

Size

Size is unavailable

Temporal Range

Santonian stage of the late Cretaceous epoch, about 85 million years ago

Ecological niche

small insectivore

Species/Sub Species

A. manazzonei

Diet

Achillesaurus, like many other alvarezsaurs, would have been adapted to an insectivorous lifestyle

Introduction

Achillesaurus is a genus of alvarezsaurid theropods that lived in Argentina during the Late Cretaceous. Achillesaurus is named after Achilles and his famous weak heel despite his exceptional powers, which is diagnostic in Achillesaurus's heel as well. Achillesaurus is currently identified as a relatively large and basal alvarezsaur while also being contemporary to Alvarezsaurus. The genus is based on a partial skeleton, sacral vertebrae, 4 caudal (tail) vertebrae, a portion of the left femur (thighbone), a tibia (shinbone), 1 foot, and an ilium. The describers of the genus, Agustín Martinelli and Ezequiel Vera, made a phylogenetic analysis on Achillesaurus and identified it as an alvarezsaurid as well as an uncertain relationship with the contemporary Alvarezsaurus and  other more advanced alvarezsaurids. In 2012, others argued that Achillesaurus may be a junior synonym of Alvarezsaurus since they think it is evident due to the fact that they are both from the same formation and are not significantly different. Achillesaurus lived with other South American paleofauna including the snake necked turtle Lomalatachelys, the snake Dinilysia, a myriad of crocodilians which occupy different ecological niches, 4 genera of titanosaurs, the ceratosaurians Viavenator and Velocisaurus (not to be confused with Velociraptor), the apex predator and megaraptoran Tratayenia, its contemporary relative  Alvarezsaurus, the oldest flightless bird Patagopteryx, and the basal ornithopod Mahuidacursor.