''Flabellisphinctes'' is small, evolute

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) ...

genus from the upper Middle Jurassic ( Callovian) that lived between 160 and 154 Ma ago. ''Flabellisphinctes'' is included in the subfamily Grossouviinae which is part of the Perisphinctidae. The shell is around 5 cm (abt. 2in) in diameter, with close spaced radial ribs on the inner whorls. Outer whorls with ribs widely spaced, coming off the umbilical shoulder and flattening about mid flank, but dividing near the ventrolateral shoulder into well defined ribs that cross the venter with a kink mid way. Whorl section, suboval compressed with a narrowly arched rim.

References

Jurassic ammonites Ammonitida genera Fossils of France Callovian life {{ammonite-stub