Collina (ammonite)

Collina is genus of ammonite that lived during lower to upper Toarcian stage of early Jurassic. Members of this genus existed from Braunianus Subzone to Variabilis Zone. Their fossils were found in Europe, Asia, North America and South America.^[1] It has evolved from Mesodactylites.^[2]

Collina Temporal range: Toarcian PreꞒ Ꞓ O S D C P T J K Pg N [1]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	†Ammonoidea
Order:	†Ammonitida
Family:	†Dactylioceratidae
Subfamily:	†Dactylioceratinae
Genus:	†Collina Hyatt, 1867
Type species
Collina gemma Buckman, 1927
Species
C. gemma Buckman, 1927 C. kampemorpha Kottek, 1966
Synonyms
Mucrodactylites Buckman, 1927 Collinites Bonarelli, 1899

Description

Whorl section is angular quadrate. Distant ribs can be bifurcating or trifurcating on the place of high ventrolateral tubercules. Secondary ribs are bent strongly forward and raised in the middle part of the venter. Size dimorphism is present in the case of this genus.^[1]