''Transicoeloceras'', which is sometimes considered to be a synonym of ''
Catacoeloceras
''Catacoeloceras'' is a genus of ammonite that lived during Middle Toarcian stage of early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earl ...
''
[M. K. Howarth 2013. Treatise on Invertebrate Paleontology, Part L, Revised, Volume 3B, Chapter 4: Psiloceratoidea, Eoderoceratoidea, Hildoceratoidea.] is genus of
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) ...
that lived during
Toarcian
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 (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
stage (Bifrons to lower Gradatus ammonite Zones) of
early Jurassic. Their fossils were found in Hungary, Italy, France, southern Spain and South America. It has evolved from ''
Mesodactylites
''Mesodactylites'', which is sometimes considered to be a synonym of '' Nodicoeloceras''M. K. Howarth 2013. Treatise on Invertebrate Paleontology, Part L, Revised, Volume 3B, Chapter 4: Psiloceratoidea, Eoderoceratoidea, Hildoceratoidea. is genus ...
''.
[
]
Description
Ammonites belonging to this genus have small shells. Coiling is involute to sphaerocone. Rounded subtrapezoid whorl section has maximum width at the shoulder. Umbilicus is deep and venter is broad and convex. Fine ribs were simple, or bifurcating and also had tubercules.[Kovács, Z. (2014). Toarcian Dactylioceratidae (Ammonitina) from the Gerecse Mts (Hungary). Hantkeniana, 9, 45-77.]
References
Ammonitida
Toarcian life
Early Jurassic ammonites of Europe
Ammonites of South America
Ammonite genera
{{Ammonite-stub