''Nanno'' is an extinct genus of

Endocerid Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian ...

, named by Clarke in 1894 for the

apical Apical means "pertaining to an apex". It may refer to: *Apical ancestor, refers to the last common ancestor of an entire group, such as a species (biology) or a clan (anthropology) *Apical (anatomy), an anatomical term of location for features loc ...

end of an

endocerid Endocerida is an extinct nautiloid order, a group of cephalopods from the Lower Paleozoic with cone-like deposits in their siphuncle. Endocerida was a diverse group of cephalopods that lived from the Early Ordovician possibly to the Late Silurian ...

from the Trenton Limestone of New York state that has the basic description of the nanno type (where the

siphuncle The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ...

swells to fill the entire apex of the shell, leaving septa and camerae to begin a few centimeters forward). It is possibly the senior

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

for ''

Proterovaginoceras ''Proterovaginoceras'' (Ancient Greek for "earlier shield horn") is a medium to large sized endocerid (endocone-bearing orthoconic nautiliod) from the Early and Middle Ordovician included in the family Endoceratidae Endoceratidae is a family ...

'' . As a valid genus, ''Nanno'' is included in the

Endoceratidae Endoceratidae is a family of large to very large straight shelled nautiloid cephalopods belonging to the order Endocerida that lived during the Middle and Late Ordovician. They include the largest known Paleozoic invertebrates, represented by '' ...

but the nanno type apex may be found in other families.

References

* Clarke, J. M. (1897)
The Lower Silurian Cephalopoda of Minnesota
In: E.O. Ulrich, J. M. Clarke, W. H. Scofield & N. H. Winchell ''The Geology of Minnesota. Vol. III, Part II, of the final report. Paleontology.'' Harrison & Smith, Minneapolis. pp. 761–812. * Flower, R. H. (1955). Status of Endoceroid Classification. Journal of Paleontology, Vol.20, no.5 May 1955,p. 329__. Abstract and Intro

* Teichert, C, (1964). Endoceratoidea; Treatise on Invertebrate Paleontology, part K. Geol Soc of America and Univ. Kansas Press. Prehistoric nautiloid genera Fossil taxa described in 1894 {{paleo-Nautiloidea-stub