Eocanites planus (Schindewolf, 1926)

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 : 209-210

Eocanites planus (Schindewolf, 1926)

Fig. 127 ; Table 123

Protocanites planus Schindewolf, 1926: 105 .

Protocanites planus planus – Vöhringer 1960: 174, pl. 6 fig. 3, text-fig. 49.

Eocanites planus – Korn 1994: 82, text-figs 73f, 74b.

Diagnosis

Species of the genus Eocanites with a conch reaching 50 mm diameter. Conch at 30 mm dm subevolute (uw/dm ~0.42) with weakly compressed whorl profile (ww/wh ~0.75) and broadly rounded venter. Ornament with very fine, rursiradiate, concavo-convex growth lines with moderately deep ventral sinus. Without ribs. Suture line with parallel-sided external lobe and lanceolate adventive lobe.

Material examined

Neotype

GERMANY • Rhenish Mountains, Oberrödinghausen , railway cutting ; Hangenberg Limestone , bed 1 ; Vöhringer Coll.; illustrated by Vöhringer (1960: pl. 6 fig. 3) and Korn (1994: text-fig. 73f); re-illustrated here in Fig. 127A ; GPIT-PV- 64009 .

Additional material

GERMANY • 1 specimen; Rhenish Mountains , Oberrödinghausen , railway cutting ; Hangenberg Limestone , loose material; Vöhringer Coll.; GPIT-PV- 63990 .

Description

Neotype GPIT-PV-64009 is a shell-covered specimen of 40 mm conch diameter embedded in a limestone block ( Fig. 127A ). The conch is extremely discoidal and subevolute (ww/dm = 0.23; uw/dm = 0.43) with a compressed oval whorl profile (ww/wh = 0.70) and a high coiling rate (WER = 2.04). The shell surface appears to be smooth.

The suture line of specimen GPIT-PV-63990 shows a parallel-walled external lobe, a symmetrically rounded ventrolateral saddle and a lanceolate adventive lobe with parallel flanks ( Fig. 127B ).

Remarks

A type specimen was not selected when Schindewolf (1926b) described the species Eocanites planus ; obviously no later author has determined a lectotype. In his monograph, Vöhringer (1960) also did not give any information on a type of the species. For this reason, a neotype from the Vöhringer Collection from the type locality is proposed here.

Eocanites planus differs from the other species of the genus from Central Europe in the narrower umbilicus and the higher coiling rate (WER exceeding 2.05); the uw/dm ratio is less than 0.45 in E. planus but 0.50 or more and the whorl expansion rate is below 2.00 in the other species.

Figures

Fig. 127. Eocanites planus (Schindewolf, 1926) from the Oberrödinghausen railway cutting. A. Lateral view and dorsal reconstruction of neotype GPIT-PV-64009 (Vöhringer Coll.) from bed 1. B. Suture line of specimen GPIT-PV-63990 (Vöhringer Coll.) from an unknown bed, at ww = 6.2 mm, wh =7.0 mm. Scale bar units= 1 mm.