The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 190.8 ± 1.5 Ma and 182.7 ± 1.5 Ma. The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian.
Temnodontosaurus is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ago (Hettangian-Toarcian) in what is now Western Europe and Chile. They lived in the deeper areas of the open ocean. University of Bristol paleontologist Jeremy Martin described the genus Temnodontosaurus as "one of the most ecologically disparate genera of ichthyosaurs".
Rhomaleosaurus is an extinct genus of Early Jurassic rhomaleosaurid pliosauroid known from Northamptonshire and from Yorkshire of the United Kingdom. It was first named by Harry Seeley in 1874 and the type species is Rhomaleosaurus cramptoni. It was one of the earliest large marine reptile predators which hunted in the seas of Mesozoic era. Its length was about 7 m (23 ft) long. Like other pliosaurs, Rhomaleosaurus fed on ichthyosaurs, ammonites and other plesiosaurs.
Harpoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had involute and compressed shells with strong keels. Keel might be rarely missing, but this is considered to be an abnormality. This has been observed both in Cleviceras and Harpoceras and called as genus Monestieria, which is now known to be invalid. Another example is Pseudolioceras, whose unkeeled specimen was used as type for description of invalid genus Praehaploceras. Oxyconic forms of this subfamily does not have any keel. Ribs were single, but in some genera also bifurcating with shapes from sigmoidal to falcate. Sometimes, shell can have only striate ribs or is smooth. Tubercules are rare. Dimorphism is known in some genera and it is observable mostly in size. Macrochons can be 4, to 6 times larger than microconchs. As an example, macroconchs of Pseudolioceras are more than 150mm in diameter, while adult microconchs are only 35-50mm. There are big size differences even within dimorphs. Specimens ca be 2, or sometimes even 3 times bigger than other specimens of same dimorph.
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.
Tokurites is a monospecific genus of ammonite that lived during the Toarcian stage of early Jurassic, ammonite zone of Zugodactylites braunianus. Its shell has ribs, which cross the ventral part of the shell creating pricky tubercules there. By these tubercules, it differs from any other member of Dactylioceratidae. This genus is closely related to genus Reynesoceras. The genus is based on the single specimen with diameter of 15 mm and thus consist from only one species Tokurites inopinatus. This is the only specimen that has been found in the Asian part of Russia.
Prodactylioceras is genus of ammonite that lived during the Pliensbachian stage of early Jurassic. It has evolved from Reynesocoeloceras, but maybe not directly, but through Bettoniceras. Its fossils were found in Europe, Asia and North America.
Porpoceras is genus of ammonite that lived during the early and middle Toarcian stage of early Jurassic. Members of this genus existed from uppermost part of the Harpoceras serpentinum zone to the Haugia variabilis zone. Their fossils were found in Europe, Asia, North America and South America.
Reynesoceras is genus of ammonites that lived during the upper Pliensbachian stage of early Jurassic. It has evolved from Prodactylioceras, or Cetonoceras. Dactylioceras (Eodactylites) has probably evolved from this genus. Aveyroniceras is a name for macroconchs of this genus. Their fossils were found in Europe, northern Africa, Asia, North America and South America.
Septimaniceras is genus of ammonites that has probably evolved from Peronoceras and lived during the middle Toarcian stage of early Jurassic. Members of this genus existed from Bifrons Subzone to lower part of Variabilis Subzone. Their fossils were found in France, Hungary and probably also in Austria.
Collina is genus of ammonite that lived during lower to upper Toarcian stage of early Jurassic. Members of this genus existed from Braunianus Subzone to Variabilis Zone. Their fossils were found in Europe, Asia, North America and South America. It has evolved from Mesodactylites.
Catacoeloceras is a genus of ammonite that lived during middle to late Toarcian stage of early Jurassic. Members of this genus existed from Bifrons Subzone of Bifrons Zone to Variabilis Zone. Their fossils were found in Europe, northern Africa, Asia, North America and South America. It has evolved from Peronoceras, or Porpoceras.
Nodicoeloceras is genus of ammonite that lived during early to middle Toarcian stage of early Jurassic. Members of this genus existed from Exaratum Subzone of Falciferum Zone to Commune subzone of Bifrons Zone. Their fossils were found in Europe, northern Africa, Asia, North America and South America. It has probably evolved from Dactylioceras (Orthodactylites) or Kedonoceras and gave rise to Mesodactylites.
Transicoeloceras, which is sometimes considered to be a synonym of Catacoeloceras is genus of ammonite that lived during Toarcian stage of early Jurassic. Their fossils were found in Hungary, Italy, France, southern Spain and South America. It has evolved from Mesodactylites.
Telodactylites, which is sometimes considered to be a synonym of Porpoceras is genus of ammonite that lived during Toarcian stage of early Jurassic. Their fossils were found in Europe, northern Africa and South America. It has probably evolved from Mesodactylites.
Microdactylites, which is sometimes considered to be a synonym of Dactylioceras, is genus of ammonite that lived during early to middle Toarcian stage of early Jurassic. Their fossils were found in England, France, Italy, Germany and Hungary. Species belonging to this genus were microconchs of Dactylioceras.
Mucrodactylites, which is sometimes considered to be a synonym of Collina, is genus of ammonite that lived during middle to late Toarcian stage of early Jurassic. Their fossils were found in Europe, northern Africa and South America. Species belonging to this genus were probably microconchs of Catacoeloceras. As macroconch of M. mucronatus is considered to be Catacoeloceras raquinianum.
Orthildaites is a genus of ammonites that lived during the lower Toarcian stage of early Jurassic, during Falciferum subzone.
The Marne di Monte Serrone is a geological formation in Italy, dating to roughly between 181 and 178 million years ago, and covering the early and middle Toarcian stage of the Jurassic Period of central Italy. It is the regional equivalent to the Toarcian units of Spain such as the Turmiel Formation, units in Montenegro, such as the Budoš Limestone and units like the Wazzant Formation and the Azilal Formation of Morocco.
