Charactoceras? sp., Foerste, 1924

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 : 57

Charactoceras? sp.

Fig. 22B

Material examined

ESTONIA • 1 spec.; Paope quarry; Kõrgessaare Formation , Vormsi Regional Stage; TUG 1006-13 .

Description

The specimen is a ca 120° long fragment of a body chamber with a broad elliptical whorl cross section. The dorsal part of the whorl is not preserved. The fragment has a shallow annulations, which run nearly directly transverse over the umbilical margin, ca 19–20 annulations occur per volution. A shallow U-shaped hyponomic sinus is apparent both from faint growth lines preserved on the mold and the shape of the annulations. The preserved part of the conch has a maximum diameter of 52 mm, and the diameter of the preceding whorl is 33 mm (WER = 2.48); at its adoral end the whorl width is 18 mm and the corresponding whorl height is 16 mm (WWI = 1.13).

Remarks

The conch shape and ornamentation of this fragmentary specimen is similar to annulated species of Charactoceras , such as C. kallholnense Frye, 1982 or C. suecicum Frye, 1982 , However, the siphuncle including the septal foramen are not preserved, making a genus determination uncertain, and the fragmentary character of this specimen does not permit species level determination.

Figures

Fig. 22.Charactoceras Foerste, 1924from thePirguRegional Stage, Estonia.A. Charactocerasestonicum Strand, 1934, specimen GIT 878-229, from Vohilaid shore (E), Vohilaid Island. B. Charactoceras? sp., specimen TUG 1006-13, from Paope quarry. C. Charactoceras sp. A, specimen GIT 878-215, from Hosholm shore (tower), Vormsi Island. D. Charactoceras sp. B, specimen GIT 878-222, from Hosholm shore (tower), Vormsi Island. E. Same specimen as in C, dorsal view. Scale bar = 10 mm, same scale in A–E.