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Temporal range: Medium Jurassic, 171.6–168.4 Ma
Lytoceratidae - Nannolytoceras tripartitum.JPG
Fossil shells of Nannolytoceras tripartitum from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Lytoceratida
Suborder: Lytoceratina
Family: Nannolytoceratidae
Genus: Nannolytoceras
Buckman 1905

Nannolytoceras is an extinct genus of lytoceratid ammonite, family Lytoceratidae, with a stratigraphic range extending from the Bajocian age to Bathonian age (Medium Jurassic).[2]


Shells of Nannolytoceras species reach a diameter of about 46–75 millimetres (1.8–3.0 in).[3][4] The shell is evolute, smooth, tubular to compressed, with a variable number of more or less regularly spaced deep constrictions.[4] The very thin ribs crossing the ventral region are barely visible. Umbilicus is relatively large. The suture line is of ammonitic type.[5] These cephalopods were fast-moving nektonic carnivores.[1]


Fossils of species within this genus have been found in the Jurassic rocks of Italy and Spain.[1]