Aulacosphinctoides

Aulacosphinctoides is an extinct ammonoid cephalopod that lived during the Late Jurassic (Late Kimmeridgian to early Tithonian), included in the ammonitid family Perisphinctidae.
The shell of "Aulacosphinctoides" is evolute, whorls broadly rounded, ribs sigmoid that mostly bifurcate, but often trifurcate, Lappets present. Closely resembles "Torquantisphinctes", differing in having more rounded or depressed whorls and more sigmoid and frequently triplicate ribbing.
The genus "Aulacosphinctoides" has been found in Somalia, northern India, Japan, Argentina, Mexico, New Zealand, and Madagascar.