Gattenpleura concava ( Vöhringer, 1960 ) Korn & Weyer, 2023

Korn, Dieter & Weyer, Dieter, 2023, The ammonoids from the Gattendorfia Limestone of Oberrödinghausen (Early Carboniferous; Rhenish Mountains, Germany), European Journal of Taxonomy 882, pp. 1-230 : 150-152

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.

Figures

Fig. 10. Early Tournaisian representative ammonoids from the Oese section, all Weyer & Korn 2000 Coll. A. Paragattendorfia sp., specimen MB.C.5262.8 from bed 22. B. Stockumites sp., specimen MB.C.5262.9 from bed 22. C. Gattenpleura concava (Vöhringer, 1960), specimen MB.C.5260.1 from bed 28. D. Weyerella molaris (Vöhringer, 1960), specimen MB.C.5260.2 from bed 28. E. Kazakhstania evoluta (Vöhringer, 1960), specimen MB.C.5258.1 from bed 30. F. Paprothites dorsoplanus (Schmidt, 1924), specimen MB.C.5262.1 from bed 22. Scale bar units= 1 mm.

Fig. 89. Gattenpleura concava (Vöhringer, 1960), holotype GPIT-PV-63926 Vöhringer Coll.) from the Oberrödinghausen railway cutting, bed 4. Scale bar units=1 mm.

Fig. 90. Gattenpleura concava (Vöhringer, 1960) from the Oberrödinghausen railway cutting. A. Cross section of paratype GPIT-PV-63920 from bed 2. B. Suture line of paratype GPIT-PV-63920 from bed 2, at dm =14.5 mm, ww =7.5 mm, wh=6.6 mm.C –E. Ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh) and whorl expansion rate (WER). Scale bar units = 1 mm.