''Chazyoceras'' ("Horn of the

Chazyan The Chazy Reef Formation is a mid-Ordovician limestone deposit in northeastern North America. It consists of some of the oldest reef systems built by a community of organisms rather than the deposit of a limited range of similar organisms, such ...

") is a moderately large

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 ...

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 '' ...

with a ''

Nanno Nanno (german: Nain, Ladin: ''Nan'') was a ''comune'' (municipality) in Trentino in the northern Italian region Trentino-Alto Adige/Südtirol, located about north of Trento. As of 31 December 2004, it had a population of 623 and an area of .All ...

'' type apex and a ventral siphuncle with a holochoanitic (where "holo" is entire, and "choan" refers to its funnel-shaped opening) wall, characteristic of the family. The siphuncle swelling at the apex is subtriangular in longitudinal profile. The endocones are of medium length. ''Chazyoceras'' was named by

Rousseau Flower Rousseau Hayner Flower (1913–1988) was an extremely prolific 20th century paleontologist, known for his eccentric personality. Career Although trained as an entomologist, and a specialist in dragonflies and orthopterans, Flower began stud ...

in 1958. The genotype is ''Chazyoceras valcourense'' which came from the Middle Chazyan (Lower Middle

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

) of Valcour Island on

Lake Champlain Lake Champlain ( ; french: Lac Champlain) is a natural freshwater lake in North America. It mostly lies between the US states of New York and Vermont, but also extends north into the Canada, Canadian province of Quebec. The New York portion of t ...

. ''Chazyoceras'' resembles ''

Perkinsoceras ''Perkinsoceras''is an endocerid genus from the Middle Ordovician (Chazyan) of Champlain Valley established by Flower in 1976, which he added to his Allotrioceratidae based on certain similarities to ''Williamsoceras'' and '' Cacheoceras'' which ...

'' which Flower included in the Allotrioceratidae - a family which Flower named and included in the Endocerida based on the strange fossil, ''

Allotrioceras ''Allotrioceras'' is a tubular fossil from the Middle Ordovician of the state of New York, collected by Rousseau H. Flower; included by him in the Endocerida and placed in a new family, the Allotrioceratidae. ''Allotrioceras'' is characterized ...

'' Both ''Chazyoceras'' and ''Perkinsoceras'' types are housed in the paleontology collection at th
New Mexico Museum and Natural History and Science
in Albuquerque, where they were transferred from Flower's collection at the New Mexico Bureau of Mines in Socorro.

References

* Flower, R. H 1958. Some Chazyan and Mohawkian Endoceratida, Jour Paleon V 32, N.2, pp 433–458, May 1858. * Flower, R.H 1976 Some Whiterock and Chazy Endooceroids, Memoir 28, Part II, New Mexico Bureau of Mines and Mineral Resources, Socorro, New Mexico * Teichert, Curt 1964. Endoceratoidea; Treatise on Invertebrate Paleontology, Part K Mollusca 3; Geol Soc of America and University of Kansas Press {{Taxonbar, from=Q5088692 Prehistoric nautiloid genera Taxa named by Rousseau H. Flower