Campbelloceras

Taxobox
fossil_range = L Ordovician
name = Campbelloceras


regnum = Animalia
phylum = Mollusca
classis = Cephalopoda
subclassis = Nautiloidea
ordo = Tarphycerida
familia = Tarpyceratidae
genus = " Campbelloceras "
genus_authority = Ulrich and Foerste, 1936

Campbelloceras: a tarphyceratid with a circular whorl section, only slightly impressed, and a siphuncle that is close to the venter in all growth stages. Differs from "Tarphyceras" in that the rate of expansion is greater, the siphuncle is proportionally largers, and a impression is shallower. "Campbelloceras" is known from the L Ord (U Canad) of North America where it is wide spread.

"Campbelloceras" may have given rise to the barrandeocerid "Plectoceras" (Plectoceratidae) through simplification of the connecting rings, and to "Tarphyceras" through tighter coiling, development of a deeper impression, and reduction in the size of the siphuncle.

"Campbelloceras" can be conceivably derived from "Estonioceras" (Estonioceratidae). The cross section of "Campbelloceras" and that of the outer whorl of "Estonioceras" are similar, except for "Campbelloceras" being slightly impressed. Both have propotionally large siphuncles, near the venter.

"Campbelloceras" was named by Ulrich and Foerste in 1936.

Refs

*Flower,R.H 1984; Bodeiceras A New Mohawkian Oxycone, with revision of the Older Barrandeocerida and Discussion of the Status of the Order; Journal of Paleontology V 58, no.6 , pp1372-1379, Nov 1984
*Furnish and Glenister 1964; Nautiloidea - Tarphycerida;K355 in the Treatise on Invertebrate Paleontology Vol K; Teichert and Moore, (eds) GSA and U of Kansas Press 1964