Fossils have been reported from the Lower Jurassic of Grimmen (Lower Toarcian, Germany) and the Middle Jurassic of Daohugou (China), which display a mixture of characters associated with Orussoidea and with basal Apocrita, thus it is impossibly to classify these specimens which one of these clades.
Toarcian |
The first remains of Dorygnathus, isolated bones and jaw fragments from the Schwarzjura, the Posidonia Shale dating from the Toarcian, were discovered near Banz, Bavaria and in 1830 described by Carl Theodori as Ornithocephalus banthensis, the specific name referring to Banz.
The specific name is derived from the name of geologist Werner Ernst, who found the fossil, holotype SGWG 85, in the summer of 1963 at a loampit near Grimmen, in strata dating from the Toarcian.
Gravisauria split off in the Early Jurassic, around the Pliensbachian and Toarcian, 183 million years ago, and Aquesbi thought that this was part of a much larger revolution in the fauna, which includes the disappearance of Prosauropoda, Coelophysoidea and basal Thyreophora, which they attributed to a worldwide mass extinction.
It is known from the holotype and only specimen, MMUM LL 8004, an almost complete, three-dimensionally preservedand and articulated skeleton, found from the Hildoceras bifrons Zone (181.2–180.7 Ma) of the Alum Shale Member, Whitby Mudstone Formation, dating to early Toarcian stage.
The holotype, which lacked an inventory number, was apparently found in the famous Posidonia Shale, marine strata dating from the middle Toarcian, as can be established from the presence of the snail Coelodiscus in the matrix rock containing the only partially prepared bones.
The first European examples (Trigonia costata Parkinson) turn up in the Lower Jurassic (Toarcian) of Sherborne, Dorset and Gundershofen, Switzerland.