Temporal range: Late Triassic, 208 Ma
Fraser et al., 2002
Fraser et al., 2002
Agnosphitys (//; "unknown begetter"; sometimes mistakenly called Agnostiphys or Agnosphytis) is a genus of dinosaur from the Late Triassic of Avon, England. It contains only one species, the type species A. cromhallensis. Its remains include an ilium, maxilla, astragalus and humerus, which date variously from the Norian and Rhaetian stages of the Late Triassic.
The type species, Agnosphitys cromhallensis, was described by Fraser, Padian, Walkden and Davis in 2002. The fossils, consisting of a partial skeleton including referred material, were found in Avon, England.
The remains of Agnosphitys defied precise classification in the original description; the describers placed it outside Dinosauria using the definition of Dinosauria outlined by Padian and May (1995) and provided (on p. 80) the following diagnosis: "Well-defined brevis fossa on the ilium; semi-perforate acetabulum; `kidney-shaped' antitrochanter; well-developed posterior portion of the iliac blade; two sacral vertebrae; subrectangular deltopectoral crest that is 33 per cent of the length of the humerus; astragalus with a distinct ascending process and a prominent depression immediately posterior to the ascending process; in dorsal aspect an acute anteromedial corner on the astragalus."
Despite the paucity of known fossils, Agnosphitys has been included in two phylogenetic analyses analyzing primitive dinosaur relationships. Yates (2007) recovered the genus as a theropod, whereas Ezcurra (2010) recovered it as a member of Guaibasauridae. More recently, Agnosphitys has been considered a silesaurid based on an as-yet-unpublished description of Asilisaurus.
- Fraser, Padian, Walkden and Davis, 2002. Basal dinosauriform remains from Britain and the diagnosis of the Dinosauria. Palaeontology. 45(1), 79-95.
- Nesbitt, Sidor, Irmis, Stocker, Angielczyk, and Smith, 2015. THE ANATOMY OF ASILISAURUS KONGWE (DINOSAURIFORMES: SILESAURIDAE) AND CLOSELY-RELATED TAXA PROVIDES NEW INSIGHTS INTO THE ANATOMICAL AND CHRONOLOGICAL EVOLUTION OF DINOSAURIFORMS. Journal of Vertebrate Paleontology 35 (Supplement):187A-188A.
- Langer, 2004. Basal Saurischia. In Weishampel, Dodson and Osmolska. The Dinosauria Second Edition. University of California Press. 861 pp.
- Yates, 2007. Solving a dinosaurian puzzle: the identity of Aliwalia rex Galton. Historical Biology. 19(1), 93-123.
- Ezcurra, 2010. A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: A reassessment of dinosaur origin and phylogeny. Journal of Systematic Palaeontology. 8(3), 371-425.
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