Cingulochitina dreyenensis VERNIERS , 1999

Morávek, Radek, 2009, Lower Wenlock Chitinozoa From The Bykoš Locality (Silurian, Prague Basin, Barrandian Area, Czech Republic), Acta Musei Nationalis Pragae Series B 65 (1 - 2), pp. 37-60 : 40-41

Cingulochitina dreyenensis VERNIERS, 1999

Pl. 2, figs. 2-4, 7; pl. 7, figs. 6-9.

1979 Linochitina sp. C ; Verniers et Rickards, p. 157, pl. 1, figs. 11-12.

1979 Linochitina sp. D ; Verniers et Rickards, p. 157, pl. 1, figs. 13-14.

1981 Linochitina sp. C ; Verniers, p. 171, pl. 2, fig. 20.

1981 Linochitina sp. D ; Verniers, p. 171, pl. 2, fig. 25.

1982 Linochitina sp. C ; Verniers, p. 24-25, pl. 6, fig. 125; pl. 7, figs. 170-182.

1982 Linochitina sp. D ; Verniers, p. 25-26, pl. 6, fig. 123; pl. 7, figs. 183-190.

1992 Belonechitina ? sp.; Dufka, p. 119, pl. 3, fig. 4.

1995 Cingulochitina sp. C ; Grahn, fig. 6K.

cf. 1995 Cingulochitina sp. B ; Dufka, p. 142, pl. 1, fig. 6.

1999 Cingulochitina dreyenensis VERNIERS , p. 372, pl. 1, fig. 7.

D e s c r i p t i o n: Cingulochitina with trapezoid or ovoid shaped chamber. The neck is short and tapering. The flanks are straight to convex, rarely concave. The shoulders are indistinct. The maximal diameter of the vesicle is on or in vicinity of the basal edge. The basal edge is sharp to round. The base is flat to convex. A short mucron is present. The cingulum does not change the curvature of the basal edge, it is developed as a ridge, folding or thickening of the wall. The surface is smooth. Vesicles twins are often observed.

D i s c u s s i o n: Cingulochitina dreyenensis is very closely related to C. pitetensis. It is not possible to distinguish these two species by biometry. C. pitetensis posseses a flared neck, more pronounced shoulders and flexure. The maximal width of vesicle is greater than in C. dreyenensis .

Cingulochitina sp. B described by Dufka (1995) is longer and wider than C. dreyenensis . But the shape of vesicle is similar.

O c c u r r e n c e: Mehaigne area, Brabant massif,

Belgium (Verniers; 1981, 1982, 1999): late Llandovery to early Wenlock, Member MB3C to MB4.

Ithon East, Ithon West and Trecoed, Builth Wells district, Wales, UK ( Verniers, 1999): lower Wenlock to middle

Wenlock (graptolite biozone C. centrifugus and M. dubius).