The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 184.2 Ma and 174.7 ±0.8 Ma. It follows the Pliensbachian and is followed by the Aalenian.
Stephanoceras is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian. It is the type genus of the family Stephanoceratidae.
Arietites is a genus of massive, giant evolute, psiloceratacean ammonites in the family Arietitidae in which whorls are subquadrate and transversely ribbed and low keels in triplicate, separated by a pair of longitudinal grooves, run along the venter. Fossils are known world wide from the lower Sinemurian stage of the Lower Jurassic. Safari Ltd made an Arietites bucklandi figurine in 2014.
Arnioceras is an extinct genus of large, evolute, discoidal ammonite from the Lower Jurassic. The shell is normally coiled so that all whorls are exposed. Sides bear strong sharp ribs that are straight until reaching the ventrolateral edge where they swing forward and fade. The rim (venter) is keeled and free of grooves.
Berniceras is an extinct ammonite genus from the order Ammonitida that lived during the early Oxfordian stage of the Late Jurassic. Berniceras is included in the ammonite family, Oppeliidae.
Otoites is the type genus of the ammonite family Otoitidae that live during the Middle Jurassic.
Oecoptychius is an extinct genus of fossil ammonite cephalopods. The species lived during the Middle Jurassic.
Normannites is a strongly ribbed evolute Middle Jurassic genus of ammonite included in the stephanoceratoid family Stephanoceratidae.
Haplopleuroceras is a Middle Jurassic ammonite and likely member of the Hildoceratacean family Sonniniidae with which it shares the same sort of ribbing.
Psiloceras is an extinct genus of ammonite. Psiloceras is among the earliest known Jurassic ammonites, and the appearance of the earliest Psiloceras species form the definition for the base of the Jurassic. Unlike most earlier ammonites, which had complex shell shapes and ornamentation, Psiloceras had a smooth shell.
Distichoceras is a member of the Haploceratacean family, Oppeliidae, and type genus for the subfamily Distichoceratinae, found in upper Middle and lower Upper Jurassic sediments in Europe, Algeria, India, and Madagascar. The shell is essentially evolute and compressed with the outer flanks converging on a narrow, keeled venter; inner flanks which may be feebly ribbed, are separated from outer by a shallow spiral groove or band. Ribs on outer flanks end on or are looped to tall clavi that line the venter, standing above the keel.
Hecticoceras is an ammonite genus belonging to the haploceratoid family Oppeliidae, that lived during the Middle and Late Jurassic, from the Callovian. Hecticoceras may be seen as a series of some nine subgenera, beginning with the lower Callovian H. (Hecticoceras) and H. (Hecticoceratoides) and ending with the lower Oxfordian H. (Pseudobrightia) and H. (Eochetoceras). Hecticocerassensu lato and Prohecticoceras from the underlying Bathonian form the oppeliid subfamily, Hecticoceratinae.
Calliphylloceras is an ammonite belonging to the Phylloceratidae.
Lytoceras is an ammonite genus that was extant during most of the Jurassic and Cretaceous periods, and is the type genus for the family Lytoceratidae. These cephalopods were fast-moving nektonic carnivores.
Hildoceras bifrons is an extinct species of ammonite in the family Hildoceratidae. It dates from about 175 million years ago in the Early Jurassic when it was both widespread and common. Fossils have been found in North Africa and Europe, including several regions of England.
Harpoceras is an extinct genus of ammonite belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during the Toarcian age from the Falciferum zone to the Commune subzone of the Bifrons zone. They were fast-moving nektonic carnivores.
Ochetoceras is a genus of ammonites, belonging to the Oppeliidae, that lived during the Late Jurassic from the early Oxfordian to the early Tithonian, and type for the subfamily Ochetoceratinae.
Hammatoceras is a genus of ammonites belonging to the family Hammatoceratidae which lived during the Toarcian stage of the Early/Lower Jurassic between about 184 and 175 million year ago.
Cleviceras is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during Toarcian and possibly even uppermost Pliensbachian age. Sometimes, it is considered to be a synonym of Eleganticeras.
Parahildaites is genus of ammonites that lived during the lower Toarcian stage of early Jurassic, during Bifrons zone. It differs from Hildaites and Hildoceras by having smooth shell after reaching 4 cm in diameter. There is no spiral groove and on early whorls, there can be sigmoidal ribs or striae. Strong keel is bordered by flat areas or slight sulci. Its fossils were found in Saudi Arabia and Madagascar.
