Weyerella reticulum (Vöhringer, 1960)

Figs 8C, 94–95; Tables 91–92

Gattendorfia reticulum Vöhringer, 1960: 156, pl. 5 fig. 3, text-fig. 31.

Gattendorfia reticulum – Korn 1992b: 17, pl. 2 figs 34–35; 1994: 74, text-figs 65h, 67g, 68b. — Schönlaub et al. 1992: pl. 5 figs 34–35. — Korn & Weyer 2003: 100, pl. 2 fig. 5.

Diagnosis

Species of Weyerella with a conch reaching 25 mm diameter. Conch at 15 mm dm thickly discoidal, subevolute (ww/dm ~0.45; uw/dm ~0.42). Whorl profile at 15 mm dm weakly depressed (ww/wh ~1.30); coiling rate low (WER ~1.65). Venter broadly rounded, umbilical margin narrowly rounded. Growth lines coarse, wide-standing, with convex course; ventral sinus very deep. The combination of growth lines with spiral lines cause a reticulate ornament. Without constrictions on the shell surface; without internal shell thickenings. Suture line with narrowly lanceolate, pouched external lobe and very narrow, lanceolate adventive lobe.

Material examined

Holotype

GERMANY • Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 6; Vöhringer Coll.; illustrated by Vöhringer (1960: pl. 5 fig. 3) and Korn (1994: text-fig. 65h); re-illustrated here in Fig. 94; GPIT-PV-63974.

Paratypes

GERMANY • 4 specimens; Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 5; Vöhringer Coll.; GPIT-PV-63975–GPIT-PV-63976, GPIT-PV-63979, GPIT-PV-63991 .

Additional material

GERMANY • 1 specimen; Rhenish Mountains, Hasselbachtal; Hangenberg Limestone, bed 62A; Weyer 1993–1994 Coll.; MB.C.5242.1 .

Description

Holotype GPIT-PV-63974 has almost 15 mm conch diameter and is well-preserved and covered with shell remains (Fig. 94). The conch is discoidal and subevolute (ww/dm = 0.46; uw/dm = 0.43) with weakly depressed, continuously rounded whorl profile. The shell surface shows a combination of coarse growth lines, which are directed backwards already on the umbilical wall and flank and form a deep and broad ventral sinus, and spiral lines, which are less prominent than the growth lines. Shell constrictions are not present.

The suture line of paratype GPIT-PV-63975 is characterised by very narrow lobes (Fig. 95B). The external lobe is lanceolate and weakly pouched; next to it follows the weakly asymmetrical ventrolateral saddle and then the symmetrical, lanceolate adventive lobe, which has almost the same shape as the external lobe.

The sectioned paratype GPIT-PV-63991 shows only the whorl up to 5.5 mm conch diameter (Fig. 95A). The whorl profile is always crescent-shaped with a slowly decreasing ww/wh ratio from about 2.00 at 2 mm conch diameter to about 1.70 at 5.5 mm dm (Fig. 95E).

Remarks

Weyerella reticulum is easily distinguished from the other species of the genus by its reticulate ornament.