| Achillesaurus | |
|---|---|
 | |
| Illustration | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Genus: | †Achillesaurus |
| Species: | †A. manazzonei |
| Binomial name | |
| †Achillesaurus manazzonei Martinelli & Vera 2007 | |
Achillesaurus is agenus ofalvarezsauridtheropoddinosaur from theSantonian-aged (Late Cretaceous)Bajo de la Carpa Formation ofRio Negro,Argentina. It contains one species,Achillesaurus manazzonei.
The holotype specimen ofAchillesaurus,MACN-PV-RN 1116, was discovered in 1995 by a team of theMuseo Argentino de Ciencias Naturales “Bernardino Rivadavia” led byDr. José F. Bonaparte. It was found in thePaso Córdova Locality,Río Negro Province, northernPatagonia, where the Santonian-aged Bajo de la Carpa Formation outcrops.[1]
Its genus name was chosen in reference toAchilles'heel, because diagnostic features are found there for these animals, while the species name honors Professor Rafael Manazzone, an amateur paleontologist whose knowledge of Patagonian fossils and localities assisted the researchers on their field trips.[1]
The genus was a relatively large,basal alvarezsaurid, and a contemporary ofAlvarezsaurus. It is only known from MACN-PV-RN 1116, a partialskeleton including asacralvertebra, four tail vertebrae, part of the leftthighbone,shin and foot, and the leftilium. Agustín Martinelli and Ezequiel Vera, who described the specimen, performed aphylogenetic analysis and found their new genus to be an alvarezsaurid with an unresolved relationship toAlvarezsaurus and morederived alvarezsaurids.[1]
However, Makovicky, Apesteguía & Gianechini (2012) argued thatAchillesaurus might actually be ajunior synonym ofAlvarezsaurus, which, according to the authors, "is known from the same formation and from which it [i.e.Achillesaurus] differs trivially."[2]
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