Chazyoceras is a moderately large endocerid included in the Endoceratidae

Endoceratidae

The 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...

 with a Nanno type apex and a ventral siphuncle

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 Spirula...

 with a holochoanitic wall, characteristic of the family. The siphuncle swelling at the apex is subtriangular in longitudinal profile. Endocones are of medium length.

Chazyoceras was named by Rousseau Flower in 1958. The genotype is Chazyoceras valcourense which came from the middle Chazyan (lower middle Ordovician) of Valcour Island on Lake Champlain

Lake Champlain

Lake Champlain is a natural, freshwater lake in North America, located mainly within the borders of the United States but partially situated across the Canada—United States border in the Canadian province of Quebec.The New York portion of the Champlain Valley includes the eastern portions of...

. Chazyoceras resembles Perkinsoceras

Perkinsoceras

Perkinsocerasis an endocerid genus from the Middle Ordovician of Champlain Valley established by Flower in 1976, which he added to his Allotrioceratidae based on certain similarities to Williamsoceras and Cacheoceras which had been added previously.Perkinsoceras is characterized by a large ventral...

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

Allotrioceras

Allotrioceras is a tubular fossil from the middle Chazyan of New York state, collected by Rousseau H. Flower and included by him in the Endocerida and placed in a new family, the Allotrioceratidae...

Both Chazyoceras and Perkinsoceras types are housed in the paleontology collection at the New Mexico Museum and Natural History and Science in Albuquerque New Mexico

New Mexico

New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

. where they were transferred from Rousseau Flower's collection at the New Mexico Bureau of Mines in Socorro, New Mexico

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