''Rhabdiferoceras'' is an extinct genus of

orthocerid Orthocerida, from Ancient Greek ὀρθός (''orthós''), meaning "straight", and κέρας (''kéras''), meaning "horn", also known as the Michelinocerida, is an order of extinct orthoceratoid cephalopods that lived from the Early Ordovician ...

s belonging to the

Baltoceratidae Baltoceratidae is an extinct family of orthoconic cephalopods belonging to the subclass Nautiloidea endemic to what would be Asia, Australia, Europe, North America, and South America during the Ordovician living from about 480–460 mya, exist ...

that lived in what would be

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

during the Cassinian Stage at the end of the Early

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

, existing for approximately two million years from about 474 -472 mya.

Taxonomy

''Rhabdiferoceras'' was named by Flower (1964). Its type is ''Rhabdiferoceras annuliferum''. It was assigned to ''

'' by Flower (1964) and Hook and Flower (1977).R. H. Flower. 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda). State Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Memoir 12:234S. C. Hook and R. H. Flower. 1977. Late Canadian (Zones J, K) cephalopod faunas from Southwestern United States. New Mexico Bureau of Mines and Mineral Resources 32:1-56

Morphology

''Rhabdiferoceras'' is a rod-bearing baltoceratid with undulations on the dorsal side of the ventral siphuncular rod that correspond to the segments of the siphuncle. Septal necks are very short, connecting rings are layered and are slightly expanded and gently convex from the outside. The genotype, ''Rhadiferoceras annuliferum'' Flower is known only from sectioning a limestone block, presumed to be of Cassinian age from the Pogonip Group from the northern end of the Ely Springs Range, Nevada. The siphuncle is rather large, in proportion, and slightly removed from the venter, considered a baltoceratid aspect. We can only guess at what the animal may have been like or as to its habits. As an orthocerid it may have had 8 or 10 long arms or tentacles projecting from its head, as found in modern

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

belemnite Belemnitida (or belemnites) is an extinct order (biology), order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous (And possibly the Eocene). Unlike squid, belemnites had an internal skeleton that made up the cone ...

s, and indicated for Upper Ordovician '' Orthonybyoceras'' and Silurian ''

Michelinoceras ''Michelinoceras'' is the oldest known genus of the Michelinocerida, more commonly known as the Orthocerida, characterized by long, slender, nearly cylindrical orthocones with a circular cross section, long camerae, very long body chambers, and a ...

''.

References

{{Taxonbar, from=Q7319959 Prehistoric cephalopod genera Ordovician cephalopods of North America Orthocerida