Streptochetus Cossmann 1889

Streptochetus? sp. B

Figs 30 P–Q

Material. A single nearly complete external mould. MGUH 33254 consists of the protoconch and initial six teleoconch whorls collected south of Højerup, Stevns Klint.

Occurrence. The Cerithium Limestone Member south of Højerup, Stevns Klint.

Description. Protoconch obtusely conical, consisting of two smooth whorls with distinct sutural angle; initial whorl small, not inflated.

Teleoconch high-spired, consisting of moderately convex whorls; whorls low, their height corresponding to nearly half their width. Narrow suture located in distinct angle between succeeding whorls, and bordered by weak subsutural collar. Aperture unknown.

Teleoconch sculpture dominated by around 10 strong, rounded transverse ribs partly aligned from whorl to whorl. Ribs giving the whorls a more convex outline. Interstices more or less equal in width to ribs. Spiral riblets strong and sharp, numbering around six. Transverse ribs fading out at transition to base, which is dominated by close lying spiral riblets, becoming gradually finer towards canal.

Measurements. Specimen, MGUH 33254 is more than 6.5 mm high and 2.6 mm wide, consisting of the protoconch and initial six teleoconch whorls. Exposed part of protoconch is 0.6 mm wide and 0.4 mm high.

Remarks. Streptochetus? sp. B differs from Streptochetus sp. A described above from the same beds by the more opisthocline transverse ribs and the weak subsutural collar.