Mucrodactylites

Mucrodactylites, which is sometimes considered to be a synonym of Collina, is genus of ammonite that lived during middle to late Toarcian stage (Bifrons Subzone to lower Variabilis ammonite Zone) 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.

Description
Ammonites belonging to this genus have small, evolute and compressed shells with suboval to subquadrate whorl section. Primary ribs are strong, simple and bifurcating. Secondary ribs are projected.