Halloceras
Encyclopedia
Halloceras is a gyroconic rotoceratid
from the Lower Devonian
of North America, with a subtriangular whorl section, narrow dorsum (on the inner side), divergent flanks, and broad, rounded venter (on the outer side), frills at various growth points, suture with shallow ventral and lateral lobes, and a small siphuncle near the venter.
Halloceras was named by Hyatt in 1884. The type us Halloceras undulatum.
Rutoceratidae
The Rutoceratidae are the prototypical nautilids, derived probably from either the Brevicoceratidae or Acleistoceratidae of the Oncocerida early in the Devonian...
from the Lower Devonian
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
of North America, with a subtriangular whorl section, narrow dorsum (on the inner side), divergent flanks, and broad, rounded venter (on the outer side), frills at various growth points, suture with shallow ventral and lateral lobes, and a small siphuncle near the venter.
Halloceras was named by Hyatt in 1884. The type us Halloceras undulatum.