''Garryoceras'' is an extinct genus, probably from the actively mobile carnivorous

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

order

Orthocerida Orthocerida is an order of extinct Orthoceratoid cephalopods also known as the Michelinocerida that lived from the Early Ordovician () possibly to the Late Triassic (). A fossil found in the Caucasus suggests they may even have survived until ...

, that lived in what would be North America during the Late Ordovician, from 460.5—443.7

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, existing for approximately .

Taxonomy

''Garryoceras'' was named by

Foerste Foerste is a surname. Notable people with the surname include: * August Foerste (1862–1936), American geologist, science teacher, and paleontologist * Maxime Foerste (born 1991), German actress See also * Renata Forste, American sociologi ...

(1925) and was assigned to the Orthocerida by Teichert et al. (1964) ''Garryoceras'' was listed in the

Endocerida 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 Silu ...

by Sepkoski (2002).

Morphology

The shells of ''Garryoceras'' are depressed

orthocone An orthocone is an unusually long straight shell of a nautiloid cephalopod.; During the 18th and 19th centuries, all shells of this type were named ''Orthoceras'', creating a wastebasket taxon, but it is now known that many groups of nautiloids d ...

s (height less than width), described as having a flattened dorsum and more narrowly rounded venter,Sweet 1964, Garryoceras K2590-K260 in Nautiloidea-Orthocerida, Treatise on Invertebrate Paleontology Part K, Teichert and Moore (eds), Geological Society of America and University of Kansas press. in other words boatlike. Camerae are short. Sutures form broad, shallow dorsal lobes and slope toward the apex going from the dorsum to the venter. The sipuncle is small, subcylindrical, and close to the venter. Internal details are unknown.

Fossil distribution

Fossil distribution is exclusive to the Putnam Highland, Canada.

References

{{Taxonbar, from=Q5524265 Cephalopod genera Ordovician cephalopods of North America Paleozoic life of the Northwest Territories