Nannolytoceras Explained

Nannolytoceras is an extinct genus of lytoceratid ammonite, family Lytoceratidae, with a stratigraphic range extending from the Bajocian age to Bathonian age (Medium Jurassic).^[1]

Description

Shells of Nannolytoceras species reach a diameter of about 46-.^{[2] [3]} The shell is evolute, smooth, tubular to compressed, with a variable number of more or less regularly spaced deep constrictions.^[3] The very thin ribs crossing the ventral region are barely visible. Umbilicus is relatively large. The suture line is of ammonitic type.^[4] These cephalopods were fast-moving nektonic carnivores.^[5]

Distribution

Fossils of species within this genus have been found in the Jurassic rocks of Italy, Spain,^[5] Slovakia,^[6] and France.^[7]

Notes and References

1. Sepkoski . Jack . A compendium of fossil marine animal genera (Cephalopoda entry) . Bulletins of American Paleontology . 363 . 1–560 . 2002 . 2017-10-18.
2. http://jsdammonites.fr/381.html Ammonites Nannolytoceras - Nannolytoceras tripartitum
3. http://www.ammonites.fr/Fiches/0620.htm Ammonites.fr
4. http://www.redjaen.es/francis/?m=c&o=29577 Redjaen
5. http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=15222&is_real_user=1 Paleobiology Database - Nannolytoceras
6. Schlögl Ján (2001). Sedimentológia a biostratigrafia červených hľuznatých vápencov čorštýnskeho súvrstvia ("Ammonitico Rosso") v pieninskom bradlovom pásme.
7. Pavia. Giulio. Fernández-López. Sixto. Mangold. Charles. 2008-07-01. Ammonoid succession at the Bajocian-Bathonian transition in the Bas Auran area, Digne District, South-East France. Rivista Italiana di Paleontologia e Stratigrafia. 114. 287–311.. 10.13130/2039-4942/5903.