Cyptendoceratidae Zhuravleva, 1994

Kröger, Björn & Pohle, Alexander, 2021, Early-Middle Ordovician cephalopods from Ny Friesland, Spitsbergen - a pelagic fauna with Laurentian affinities, European Journal of Taxonomy 783 (1), pp. 1-102 : 44

Family Cyptendoceratidae Zhuravleva, 1994

Emended diagnosis

Straight longicones with siphuncle marginal or submarginal, relatively wide with concave or convexoconcave segments; septal necks short, loxochoanitic to orthochoanitic; connecting rings relatively thick; endosiphuncular deposits form thick ventral rod which merges adapically into a complete siphuncular filling, diaphragms unknown; cameral deposits epi- and hyposeptal, concentrated on prosiphuncular side.

Remarks

The diagnosis of the Cyptendoceratidae largely follows Zhuravleva (1994), but is more restricted following the emendation of the Baltoceratidae by Kröger et al. (2007), in which rod-bearing smooth longicones with tubular siphuncles, such as Rangeroceras Hook & Flower, 1977 , Rhabdiferoceras Flower, 1964 and Veneficoceras Hook & Flower, 1977 , are now included within the Baltoceratidae . The family now contains rod-bearing smooth and annulated forms with concave siphuncular segments and includes four genera: Cyptendoceras Ulrich & Foerste, 1936 , Amsleroceras Hook & Flower, 1977 , Catoraphiceras Ulrich & Foerste, 1936 , and Hemichoanella Teichert & Glenister, 1954 .