Protocycloceras Hyatt 1900

• Main Authors: Kröger, Björn, Pohle, Alexander
• Format: Text
• Language: unknown
• Published: Zenodo 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Cephalopoda; Tetrabranchia; Protocycloceratidae; Protocycloceras; Hyatt; Ny Friesland; Spitsbergen
• Online Access: https://dx.doi.org/10.5281/zenodo.5793548; https://zenodo.org/record/5793548

Genus Protocycloceras Hyatt, 1900 Type species Orthoceras lamarcki Billings, 1859, from the Fort Cassin Formation (Floian Stage), Township of Godmanchester, Huntingdon County, southwest Quebec; by original designation. Diagnosis Nearly straight, annulated longicones with circular or subcircular cross section and straight sutures; camerae narrow, about 6–7 over a length similar to conch cross section; siphuncle located between center and ventral conch margin; siphuncular segments concave; septal necks short, loxochoanitic to orthochoanitic; connecting ring comparatively thick; siphuncular deposits wedge out adorally at steep angle to ventral side; diaphragms in apical portions of siphuncle; epi-and hyposeptal cameral deposits more strongly developed on ventral side (adopted from Kröger & Landing 2009). Remarks The genus Protocycloceras is type genus for the Protocycloceratidae Kobayashi, 1935. Based on the cladistic analysis (below) this family is abandoned. The genus clusters consistently with other members of the Troedsonellida, such as Buttsoceras (see below). The close relationship between the two genera is also suggested by the combination of diaphragms and endosiphuncular linings, which is unknown in any other genus. : Published as part of Kröger, Björn & Pohle, Alexander, 2021, Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities, pp. 1-102 in European Journal of Taxonomy 783 (1) on pages 52-53, DOI: 10.5852/ejt.2021.783.1601, http://zenodo.org/record/5793422 : {"references": ["Billings E. 1859. Fossils of the calciferous sandrock, including those of a deposit of White Limestone at Mingan, supposed to belong to the formation. Canadian Naturalist and Geologist, Proceedings of the Society of Natural History Montreal 4: 345 - 367.", "Kroger B. & Landing E. 2009. Cephalopods and paleoenvironments of the Fort Cassin Formation (Upper Lower Ordovician), eastern New York and adjacent Vermont. Journal of Paleontology 83: 664 - 693. https: // doi. org / 10.1666 / 08 - 181.1"]}