Pentameroceras

Pentameroceras
Temporal range: M Silurian
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Nautiloidea
Order: Oncocerida
Family: Trimeroceratidae
Genus: Pentameroceras
Hyatt, 1884

Pentameroceras is a straight to slightly exogastric breviconic oncocerid from the middle Silurian of North America and Europe belonging to the Trimeroceratidae.

This nautiloid cephalopod produced a straight to slightly exogastric shell with a variable cross section that is generally circular, in which septa are close spaced and transverse, the body chamber is inflated. The aperture, which is constricted, consists of a narrow, vertical slit-like opening extending from the ventral hyponomic sinus to a dorsal sinus and two pairs of lateral sinuses that diverge in the upper portion. Siphuncles in the Trimeroceratidae are slender and empty.

References

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