''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 of
ammonite that lived during early to middle
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 (Serpentinum to Bifrons ammonite Zones) of
early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...
. Their fossils were found in southern and central Europe and northern Africa. It has evolved from ''Nodicoeloceras''.
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Description
Ammonites belonging to this genus have small to medium-sized shells. Coiling is cadicone to moderately evolute. Subcircular whorl section has convex flanks and rounded venter. Ribs can be simple or bifurcating. On ventrolateral position, there are tubercules, mostly on phragmocone
The phragmocone is the chambered portion of the shell of a cephalopod. It is divided by septa into camerae.
In most nautiloids and ammonoids, the phragmocone is a long, straight, curved, or coiled structure, in which the camarae are linked by a ...
.[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 Africa
Ammonite genera
{{Ammonite-stub