Chidleyenoceras is a Middle Ordovician tarphyceroid with a closely coiled, evolute shell; whorl section subquadrate, widest just above a broadly rounded venter; dorsum with a broad shallow impression; sutures moderately spaced, weakly sinuous; siphuncle large, subventral, apparently orthochoantitic[clarification needed] with tubular segments.
| Chidleyenoceras Temporal range: Middle Ordovician
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| Genus: | Chidleyenoceras Shimizu & Obata, 1935
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The tubular, subventral siphuncle separates Chidleyenoceras from the Apsidoceratidae (Sweet, 1964) where it had been included and puts it well into the Plectoceratidae (Flower, 1984).
References edit
- Flower, (1984). Bodeiceras; a New Mohawkian Oxycone, with Revision of the Older Barrandeocerida and Discussion of the Status of the Order. Journal of Paleontology v. 58, no.6, pp 1372–1379, Nov. 1984.
- Walter C Sweet, 1964 Nautiloidea-Barrandeocerida; Treatise on Invertebrate Paleontology Part K Mollusca 3. Geological Society of America and University of Kansas Press.