Kingdom Animalia Class Cephalopoda Order Tarphycerida | Phylum Mollusca Subclass Nautiloidea Rank Family | |
Similar Tarphycerida, Ophioceras, Discosorida, Nautiloid, Nautilida | ||
The Ophidioceratidae are a family of closely coiled tarphycerids, represented solely by the Upper Silurian genus, Ophioceras, characterized by an evolute shell with narrow, subrounded, annulated whorls and a subcentral siphuncle composed of thin connecting rings that show no evidence of layering. The mature body chamber is strongly divergent and is the longest proportionally of any tarphycerid. The aperture has a deep hyponomic sinus and ocular sinuses, and so resembles some lituitids.
The Ophidioceratidae seem to have their origin in the Trocholitidae, possibly in Graftonoceras.
References
Ophidioceratidae Wikipedia(Text) CC BY-SA