Gattenpleura concava (Vöhringer, 1960) comb. nov.

Figs 10C, 89–90; Tables 87–88

Gattendorfia concava Vöhringer, 1960: 157, pl. 5 fig. 2, text-fig. 32.

Gattendorfia concava – Korn 1994: 74, text-figs 65d, 66k, 67f. — Kullmann 2000: text-fig. 4l; 2009: text-fig. 3.6c. — Korn & Weyer 2003: 100, pl. 2 figs 16–17.

Diagnosis

Species of Gattenpleura with a conch reaching 30 mm diameter. Conch at 15 mm dm thickly discoidal, subinvolute (ww/dm ~0.48; uw/dm ~0.22). Whorl profile at 15 mm dm weakly compressed (ww/wh ~0.95); coiling rate low (WER ~1.70). Venter rounded, umbilical margin raised and narrowly rounded, accompanied by a dorsolateral spiral groove. Growth lines very fine, narrow-standing, with convex course. With shallow constrictions on the shell surface; with weak internal shell thickenings. Suture line with narrowly lanceolate external lobe and V-shaped adventive lobe.

Material examined

Holotype

GERMANY • Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 4; Vöhringer Coll.; illustrated by Vöhringer (1960: pl. 5 fig. 2) and Korn (1994: text-fig. 65d); re-illustrated here in Fig. 89; GPIT-PV-63926.

Paratype

GERMANY • Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 4; Vöhringer Coll.; GPIT-PV-63920 .

Additional material

GERMANY • 1 specimen; Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 3c; Vöhringer Coll.; MB.C.31175 • 1 specimen; Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 3e; Vöhringer Coll.; MB.C.31176 • 1 specimen; Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 3a; Weyer 1993–1994 Coll.; MB.C.31177 • 1 specimen; Rhenish Mountains, Oese, old quarry; Hangenberg Limestone, bed 28; Weyer & Korn 2000 Coll.; MB.C.5260.1.

Description

Holotype GPIT-PV-63926 is a moderately well-preserved specimen with 19 mm conch diameter (Fig. 89). The conch is thinly discoidal and involute (ww/dm ~0.42; uw/dm ~0.10) with a moderate coiling rate (WER = 1.75). The whorl profile is characteristic with a slightly raised umbilical margin, which is accompanied on the flank by a shallow spiral groove; the venter is broadly rounded. The shell ornament consists of delicate growth lines with convex course.

The sectioned paratype GPIT-PV-63920 provides a view into the conch ontogeny between 2.5 and 18 mm diameter (Fig. 90A). In this interval, the whorl profile changes from originally crescent-shaped to circular to slightly compressed. The dorsolateral groove is formed at about 12 mm conch diameter. The suture line of the paratype has a lanceolate external lobe, inverted U-shaped ventrolateral saddle and a V-shaped adventive lobe with slightly convex flanks (Fig. 90B).

Remarks

Gattenpleura concava differs from the other species of the genus by the lack of radial folds.