Laumontoceras
Encyclopedia
Laumonttoceras is a genus in oncocerid family Jovellaniidae
from the lower Devonian
of Europe characterized by uncompressed, moderately expanding, orthocones with a central siphuncle composed of cylindrical segments that are slightly contracted at the septal openings and which contain discrete, discontinuous actinosphonate deposits.
Laumontoceras differs from Jovellania
, also from the lower Devonian of Europe, primarily in having a central rather than a subventral siphuncle, as in Jovellania.
Jovellaniidae
Jovellaniidae was established as a family within the Oncocerida to include genera characterized by longiconic orthocones and cyrtocones with a subtriangular to depressed cross-section in which the ventral side is typically angular or more acutely rounded than the dorsal side, and in which the...
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 Europe characterized by uncompressed, moderately expanding, orthocones with a central siphuncle composed of cylindrical segments that are slightly contracted at the septal openings and which contain discrete, discontinuous actinosphonate deposits.
Laumontoceras differs from Jovellania
Jovellania
Jovellania is an extinct prehistoric nautiloid genus from the order Oncocerida known from the Lower Devonian of Europe . Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera.Jovellania was named...
, also from the lower Devonian of Europe, primarily in having a central rather than a subventral siphuncle, as in Jovellania.
References
- Sweet, W. C. 1964. Nautiloidea- Orthocerida. Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ of Kansas Press. Teichert & Moore, (eds)