Kiaeroceras sp. A

Kiaeroceras sp. A

Fig. 40A, D View Fig

Material examined

ESTONIA • 1 spec.; Hiumaa Island, Kõrgessaare quarry ; Kõrgessaare Formation , Vormsi Regional Stage; TUG 895-69 .

Description

The specimen is a fragment of a mature body chamber and phragmocone. The conch height and width at the base of the body chamber are 41 mm and 37 mm, respectively (CHI = 1.1). The conch is nearly straight. The conch cross section is elliptical. The length of the body chamber is not fully preserved, it was longer than 37 mm. In lateral view, margins of the body chamber are slightly convex; the body chamber reaches its greatest height of 42 mm ca 23 mm from the base. At the base of the body chamber, a ca 3 mm thin band of oncomyarian muscle scars is preserved. Five chambers of the phragmocone are preserved, indicating a low angle of expansion, which cannot be measured because of the incomplete preservation. Septal crowding of the adoral-most septa indicates maturity of the specimen. The sutures form very shallow lateral lobes. The siphuncle is located close to the conch margin and expands between the septal foramens toward a width of ca 5 mm. The width of the septal foramen is ca 4 mm where the conch height is 38 mm (RSH = 0.11, RSS = 1.25), and the septal distance is 5 mm (RCL = 0.13, SCR = 1).

Remarks

This fragment differs from K. kaebliki sp. nov. in its larger in adult size, and less compressed, more equally rounded conch cross section.