Nanno (genus)

Nanno in cephalopod paleontology, as commonly used, refers to endocerids in which the siphuncle swells to fill the entire apex of the shell, leaving septa and camerae to begin a few centimeters forward, having a morphologic rather than a taxonomic connotation.

The term is based on the genus Nanno, named by Clarke in 1894 for the apical end of an endocerid from the Trenton Limestone of New York state that has the basic description, possibly the senior synonym for Proterovaginoceras . As a valid genus, Nanno is included in the Endoceratidae but the nanno type apex may be found in other families.