Unquillosaurus

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Unquillosaurus
Temporal range: Late Cretaceous, 75 Ma
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Dromaeosauridae
Subfamily: Unenlagiinae
Genus: Unquillosaurus
Powell, 1979
Species: U. ceibalii
Binomial name
Unquillosaurus ceibalii
Powell, 1979

Unquillosaurus (meaning "Unquillo river lizard") is a genus of maniraptoran dinosaur from the late Cretaceous Period, discovered in Argentina. Known only from a single fossilized pubis (a pelvic bone), its total body length may have reached 2-3 meters (6-10 ft).[1]

The type species Unquillosaurus ceibalii was described by Jaime Eduardo Powell in 1979. The generic name is derived from the river Unquillo. The specific name refers to the town El Ceibal.[2]

The holotype, PVL 3670-11, was found at Arroyo-Morterito in the Los Blanquitos Formation dating from the Campanian. It consists of a left pubis, 514 millimetres (1.686 ft) long. The specimen was re-studied by Fernando Novas and Federico Agnolin in 2004, who concluded that the orientation of the pubis had been misinterpreted: it pointed backwards, as was shown by the fossil still being attached to a displaced part of the pubic peduncle of the ilium.[3]

Powell originally assigned Unquillosaurus to the Carnosauria,[2] in 1986.[4] Novas and Agnolin in 2004 concluded from the opisthopubic pelvic anatomy that Unquillosaurus was part of the Maniraptora or at least Maniraptoriformes, and likely closely related to either the Avialae or the bird-like Alvarezsauridae; perhaps it was itself a bird, a basal member of the Metornithes.[3] In 2006 however, Novas stated that Unquillosaurus probably belonged to the maniraptoran clade Dromaeosauridae.[5]

See also[edit]

References[edit]

  1. ^ HyperWorks Reference Software (1999), "The Dinosaur Encyclopedia: Unquillosaurus", viewed December 07, 2012.
  2. ^ a b Powell, J.E. (1979). "Sobre una asociación de dinosaurios y otras evidencias de vertebrados del Cretácico Superior de la región de La Candelaria, Prov. de Salta, Argentina" ["On a dinosaur association and other evidinces of Upper Cretaceous vertebrates from the La Candelaria region, Salta Province, Argentina."] Ameghiniana, 16(1-2): 191-204. (In Spanish: English translation by Matthew Carrano, SUNY at Stony Brook, 8/99).
  3. ^ a b Novas and Agnolin, (2004). "Unquillosaurus ceibalii Powell, a giant maniraptoran (Dinosauria, Theropoda) from the Late Cretaceous of Argentina." Rev. Mus. Argentino Cienc. Nat., n.s. 6(1): 61-66.
  4. ^ Powell, J.E., 1986. Revision de los titanosauridos de America del Sur Argentina. Universidad Nacional de Tucuman, Argentina
  5. ^ R.D. Martínez and F.E. Novas, 2006, "Aniksosaurus darwini gen. et sp. nov., a new coelurosaurian theropod from the early Late Cretaceous of central Patagonia, Argentina", Revista del Museo Argentino de Ciencias Naturales, nuevo serie 8(2): 243-259