Aniksosaurus darwini gen. et sp. nov., a new coelurosaurian theropod from the Early Late Cretaceous of Central Patagonia, Argentina

• Autores: Rubén Martínez, Fernando E. Novas
• Localización: Revista del Museo Argentino de Ciencias Naturales, ISSN-e 1853-0400, ISSN 1514-5158, Vol. 8, Nº. 2, 2006, págs. 243-259
• Idioma: español
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• Resumen

  • The theropod dinosaur Aniksosaurus darwini gen. et sp. nov. has been recovered from the UpperCretaceous, Bajo Barreal Formation, of Central Patagonia. Aniksosaurus darwini gen. et sp. nov. was a smalltetanurine, approximately 2 meters long. Aniksosaurus exhibits several unique traits (e.g., cranial cervical vertebraewith dorsoventrally deep neural arches, provided with a pair of cavities at their cranial surfaces; neuralcanal wide; cranial caudals with ventral sagittal keel, and transverse processes triangular-shaped in dorsalview; manual ungual phalanges robust; ilium with extremely expanded brevis shelf; femur with deep notch forM. Iliotrochantericus; metatarsal and digit IV of pes transversely narrow). Available postcranial bones ofAniksosaurus exhibit derived features of Coelurosauria (e.g., ilium with well developed cuppedicus fossa; femurwith anterior trochanter proximally projected, almost reaching the level of the articular head; greater trochantercraniocaudally expanded; femoral head rectangular-shaped in cranial aspect; and fibular shaftcraniocaudally narrow), as well as characteristics suggesting that the new Patagonian taxon is more derivedthan some basal coelurosaurians such as compsognathids, Ornitholestes, and coelurids. Comparisons withmaniraptoriforms (a clade including Ornithomimosauria, Tyrannosauridae, Oviraptorosauria, Alvarezsauridaeand Paraves) support that Aniksosaurus is less derived than these theropods. In sum, Aniksosaurus is hereconsidered as a Late Cretaceous survivor of a basal coelurosaurian radiation.