| Agnosphitys | |
|---|---|
 | |
| Referred left maxilla | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria (?) |
| Clade: | †Ornithischia (?) |
| Family: | †Silesauridae (?) |
| Genus: | †Agnosphitys Fraseret al., 2002 |
| Species: | †A. cromhallensis |
| Binomial name | |
| †Agnosphitys cromhallensis Fraseret al., 2002 | |
Agnosphitys (/ˌæɡnoʊsˈfaɪtɪs/; "unknown begetter"; sometimes mistakenly calledAgnostiphys orAgnosphytis) is agenus ofdinosauriform that lived during the LateTriassic. It contains only one species, thetype speciesA. cromhallensis. Its remains include anilium,maxilla,astragalus andhumerus, which date variously from theNorian andRhaetian stages of theLate Triassic, or possibly as late as theHettangian stage of theEarly Jurassic.[1] The fissure fill at Avon, of whichAgnosphitys was probably recovered from, was a sinkhole formed by the dissolution ofLower Carboniferouslimestones.
The type species,Agnosphitys cromhallensis, was described byNicholas Fraser,Kevin Padian, Gordon Walkden and A. L. M Davis in early 2002.[2] The fossils consist of two specimens. The holotype consists of a single isolated left ilium, while the second specimen consists of a partial skeleton including a left maxilla, a humerus and a leftastragalus, were found in theMagnesian Conglomerate ofAvon,England.[3]
The remains ofAgnosphitys defied precise classification in the original description; the describers placed it outsideDinosauria 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-perforateacetabulum; `kidney-shaped' antitrochanter; well-developed posterior portion of the iliac blade; twosacral 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."[2]
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,[4] whereas Ezcurra (2010) recovered it as a member ofGuaibasauridae.[5] More recently,Agnosphitys has been considered asilesaurid based on an as-yet-unpublished description ofAsilisaurus.[6]
A large phylogenetic analysis of early dinosaurs anddinosauromorphs carried out by Matthew Baron,David Norman and Paul Barrett (2017) recoveredAgnosphitys as a member of the cladeSilesauridae.[7]
