Kiaeroceras sp. C

Kröger, Björn, 2025, The Lyckholm acme of cephalopods - Review of the late Katian (Vormsi-Pirgu regional stages) Ordovician cephalopods of Estonia, European Journal of Taxonomy 978, pp. 1-169 : 111-112

Kiaeroceras sp. C

Fig. 35E, G

Material examined

ESTONIA • 1 spec.; Niibi hillock ; Moe Formation , Pirgu Regional Stage; GIT 225-997 .

Description

The specimen is a nearly complete mold of a mature body chamber with height, width, and length of 53 mm, 44 mm and 75 mm, respectively (CHI = 1.11). The conch is straight and tubular. The conch cross section is oval compressed with a relatively narrow, drop-shaped margin on the prosiphuncular side. The peristome is nearly straight and a very shallow (5 mm) hyponomic sinus occurs on the prosiphuncular side. The siphuncle is nearly marginal with a septal foramen ca 8 mm in diameter, located ca 3 mm from the conch margin (RSH = 0.15, RSP = 0.16).

Comparison

This specimen differs from K. ormsoense sp. nov., to which it is otherwise similar, in having a compressed conch cross section and a longer, perfectly tubular body chamber (RBL = 1.4 as compared with RBL ca 1 in K. (?) ormsoense ).

Figures

Fig. 35 (preceding page). Oncoceratidae Hyatt, 1884 and Cyrtogomphoceratidae Flower, 1940 of the Vormsi–Pirgu regional stages, Estonia. A–B. Kiaeroceras sp. B, specimen GIT 878-161, from Saxby shore, Vormsi Island, Vormsi Regional Stage. A. View of the prosiphuncular side. B. Lateral view. C–D. Richardsonoceras priscum (Eichwald, 1860) comb. nov. from Kõrgessaare quarry, Hiiuma Island, Vormsi Regional Stage. C. Specimen GIT 426-608, lateral view. D. Specimen GIT 426-607, view of the prosiphuncular side. E, G. Kiaeroceras sp. C, specimen GIT 225-997, from Niibi hillock, Pirgu Regional Stage. E. Lateral view. G. Adapical view. F, H. Kiaeroceras (?) ormsoense sp. nov., holotype GIT 878-63, from Saxby shore (N), Vormsi Island, Vormsi Regional Stage. F. Adapical view. H. Lateral view. I. Kiaeroceras urgense sp. nov., holotype TUG 103-75, from Urge quarry, Vormsi Regional Stage. J. Kiaeroceras (?) cf. ormsoense, specimen TUG 1680-20, from Saxby shore (N), Vormsi Island, Vormsi Regional Stage. Scale bar = 20 mm, same scale in all figures.