Cleistosphinctes

Cleistosphinctes is an extinct cephalopod genus from the ammonite order that lived during the Middle Jurassic.^[1]

Cleistosphinctes Temporal range: Bajocian[1] PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Ammonoidea
Order:	Ammonitida
Superfamily:	Perisphinctoidea
Family:	Perisphinctidae
Genus:	Cleistosphinctes

Cleistosphinctes, named by Arkell, 1953, and included in the family Perisphinctidae and superfamily Perisphinctaceae, is small, compressed, evolute, with long secondary ribs and very large asymmetric spatulate lappets that embrace the sides of the preceding whorl.