Kiaeroceras (?) cf. ormsoense

Fig. 35J

Material examined

ESTONIA • 1 spec.; Vormsi Island, Saxby shore (N); Kõrgessaare Formation, Vormsi Regional Stage; TUG 1680-20 .

Description

Specimen TUG 1680-20 is a slightly endogastrically curved fragment of a mature body chamber and four chambers of the phragmocone. The conch surface is apparently smooth. At the base of the body chamber the conch height is 47 mm. The body chamber is 52 mm long, with parts of the peristome preserved. In lateral view, the dorsal and ventral margins of the body chamber are straight. The preserved part of the phragmocone is 20 mm long and increases in height from 43 mm to 47 mm (angle of expansion = 11°). At its adapical end, the conch width is 40 mm (CHI = 1.08). There, the conch cross section is elliptically rounded. The sutures are directly transverse and 6 mm apart where the conch height is 45 mm (RCL = 0.13)

Remarks

The specimen is similar in conch shape, suture spacing, suture shape and siphuncular shape and position to K. (?) ormsoense sp. nov. but differs from this species in angle of expansion and mature size. More material is needed to evaluate the interspecific variability in mature size among specimens of K. (?) ormsoense in order to establish a new species for the two specimens described above.