Estonioceratidae
| Estonioceratidae Temporal range: L Ordovician | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | Nautiloidea |
| Order: | Tarphycerida |
| Family: | Estonioceratidae Hyatt in Zittel, 1900 |
The Estonioceratidae is a family of loosely coiled tarphycerids in which the inner side of the whorls, which forms the dorsum, is rounded or flat with no impression; and in which the siphuncle, composed of thick tubular segments, is located ventrally. The Estonioceratidae seem to form a link between the ancestral Bassleroceratidae and the more tightly coiled Tarphyceratidae.
References
- Flower, R. H. 1976. Ordovician Cephalopod Faunas and Their Role in Correlation in The Ordovician System: proceedings of a Palaeontological Association symposium, Sept 1974.
- Furnish, W. M, and Glenister, Brian F. 1964. Nautiloidea – Tarphycerida; Treatise on Invertebrate Paleontology, Part K, Geol. Soc. of America, Teichert and Moore (eds.)