The subfamily Reynesocoeloceratinae comprises early Jurassic

ammonite Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...

genera that lived during Pliensbachian stage. These dactylioceratids existed from Ibex ammonite zone and died out in Spinatum zone. They have evolved from '' Metaderoceras'' and gave rise to subfamily

Dactylioceratinae The subfamily Dactylioceratinae comprises early Jurassic ammonite genera that lived during Upper Pliensbachian to Upper Toarcian stage. These dactylioceratids existed from Margaritatus ammonite Zone, when they have evolved from Reynesocoeloc ...

Description

Ammonites with depressed, cadicone, or even evolute, serpenticone shells. Tubercules might be present. Ribs can be both single, or bifurcating. Some members of this subfamily show size dimorphism. They differs from Dactylioceratinae by suture. While Reynesocoeloceratinae has on dorsal side of external lobe two major secondary lobes, this is not so in Dactylioceratinae, as there is external saddle not divided, while lateral lobe is strongly trifid.

Taxonomy

*Reynesocoeloceratinae Dommergues, 1986 **''

Reynesocoeloceras ''Reynesocoeloceras'' is genus of ammonite that lived during the lower Pliensbachian stage of early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) ...

'' Géczy, 1976 **''

Bettoniceras ''Bettoniceras'' is genus of ammonite that lived during the Pliensbachian stage of the early Jurassic. It evolved from '' Reynesocoeloceras'' in Davoei ammonite zone and died out during Margaritatus zone. It is possible that ''Prodactylioceras ...

'' Wiedenmayer, 1977 **''

Prodactylioceras ''Prodactylioceras'' is genus of ammonite that lived during the Pliensbachian stage of early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the e ...

'' Spath, 1923 **''

Cetonoceras ''Cetonoceras'' is genus of ammonite that lived during the upper Pliensbachian stage of early Jurassic. Fossils of this genus were found in Italy, France, Spain, Portugal, Hungary and Austria.Géczy, B., Meister, C. 1998. Les ammonites du Domé ...

'' Wiedenmayer, 1977

References

Dactylioceratidae Pliensbachian life Pliensbachian first appearances Pliensbachian extinctions {{ammonitina-stub