Animalia

Cyptendoceratid gen. et sp. indet.

Figs 9C, 31A–B, 32B

Specimen FMNH-P30431, from Profilstranda section, adjacent to Hinlopenstretet, Spitsbergen, from bed PO 131, 128 m above base of Olenidsletta Member, V2 b trilobite zone, Blackhillsian, Floian.

The specimen is a 20 mm long, nearly tubular fragment of a phragmocone with a circular conch cross section, 20 mm in diameter. Eight chambers occur in the length of the fragment and the sutures are straight and directly transverse. The conch surface is poorly preserved but was apparently smooth. The chambers are internally imploded and crushed, preserving only a small part of the siphuncle. This is 7 mm in diameter and positioned between the conch center and conch margin at a distance of ca 4 mm from the conch margin. The septal necks are orthochoanitic and 0.7 mm long, where the septal distance is 3 mm. The connecting ring is relatively thin compared to the septa and septal necks and concave on the dorsal side (the side directed toward the conch center), but convex on the ventral side.

The combination of a large, eccentric, but not marginal siphuncle with relatively narrowly spaced septa, partly concave connecting rings and short orthochoanitic septal necks are arguments to place this specimen in the Cyptendoceratidae. A combination of ventrally expanded and dorsally contracted siphuncular segments is not known from other cyptendoceratids. However, the limited information available from this species, based on a single relatively small fragment, does not allow for a better determination.