Oxygonioceras is a genus in the Oncocerid family, Brevicoceratidae, from the Middle Silurian of North America and Europe.
| Oxygonioceras Temporal range: M Silurian
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | †Oncocerida |
| Family: | †Brevicoceratidae |
| Genus: | †Oxygonioceras Foerste, 1925 |
Oxygonioceras, named by Foeste, 1925, has a loosely coiled, dextrally torticonic shell with a rounded dorsum on the inside of the spiral and an angular or subangular venter on the outside; suture with broad lateral lobes and ventral siphuncle with expanded, nummuloidal segments.
Although also torticonically gyroconic—having an out of plane open spiral - Oxygonioceras differs from Naedyceras and closely related genera in that the siphuncle segments are empty, rather than being actinosiphonate.
See also
editReferences
edit- Sweet. W. C. 1964. Nautiloidea-Oncocerida; Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ Kansas press, R.C. Moore (Ed)