Rodingites, 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 : 187-189

Genus Rodingites gen. nov.

urn:lsid:zoobank.org:act:37306BE3-F3E7-4834-BB63-B092BAA43545

Type species

Pseudarietites planissimus Vöhringer, 1960: 165 .

Genus diagnosis

Genus of the subfamily Pseudarietitinae with a compressed whorl profile with acute venter and an attached ventral keel. Sculpture with simple ribs or folds.

Etymology

Named after the town of Oberrödinghausen.

Genus composition

Pseudarietites planissimus Vöhringer, 1960 ; Protocanites carinatus Vöhringer, 1960 .

Remarks

The new genus is separated from Pseudarietites because of its widely umbilicate conch and the compressed whorl cross section with acute venter that bears an attached keel.

Rodingites planissimus ( Vöhringer, 1960) gen. et comb. nov.

Fig. 115A ; Table 110

Pseudarietites planissimus Vöhringer, 1960: 165 , pl. 6 fig. 13, text-fig. 42.

Pseudarietites planissimus – Weyer 1965: 449, pl. 8 fig. 3. — Korn 1994: 78, text-figs 70j, 72d; 2006: text-fig. 4g. — Sprey 2002, pl. 4 fig. 4.

Diagnosis

Species of Rodingites gen. nov. with a conch reaching 50 mm diameter. Conch at 40 mm dm extremely discoidal, evolute (ww/dm ~0.17; uw/dm ~0.50). Whorl profile at 40 mm dm weakly depressed (ww/wh ~0.65); coiling rate low (WER ~1.70). Venter acute with keel, umbilical margin rounded. Sculpture on the flank 50 sharp ribs with concave course.

Material examined

Holotype

GERMANY • Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 3a; Vöhringer Coll.; illustrated by Vöhringer (1960: pl. 6 fig. 13), Korn (1994: text-fig. 70j), Sprey (2002: pl. 4 fig. 4) and Korn (2006: text-fig. 4g); re-illustrated here in Fig. 115A ; GPIT-PV-63962.

Description

Holotype GPIT-PV-63962 is a rather complete specimen with 43 mm conch diameter and allows the study of the last two and a half whorls ( Fig. 115A ). It is a very evolute, extremely discoidal conch (ww/ dm = 0.17; uw/dm = 0.53) with a galeate whorl profile. The venter is characterised by an attached keel. The last one and a half whorls bear rounded ribs, which start on the inner half of the flank, but only become very distinct in the ventrolateral area. These ribs start at a conch diameter of about 16 mm as ventrolateral nodes. The last half whorl possesses 25 of these ribs, the spacing of which becomes increasingly smaller. They have a concave course across the flank and are truncated by the ventral keel.

Remarks

Because of the extremely discoidal conch shape, the very wide umbilicus and the dense ribbing, Rodingites planissimus gen. et comb. nov. cannot be confused with any other ammonoid species from the early Tournaisian. The most similar species is Rodingites carinatus gen. et comb. nov., but it possesses no ribs, but only flat radial folds.

Rodingites carinatus ( Vöhringer, 1960) gen. et comb. nov.

Fig. 115B ; Table 111

Protocanites carinatus Vöhringer, 1960: 170 , pl. 6 fig. 7, text-figs 47, 50.

Protocanites (Eocanites) carinatus – Weyer 1965: 458, pl. 8 figs 6–7.

Pseudarietites carinatus – Korn 1994: 77, text-figs 70f, 72e.

Diagnosis

Species of Rodingites gen. nov. with a conch reaching 30 mm diameter. Conch at 25 mm dm extremely discoidal, subevolute (ww/dm ~0.22; uw/dm ~0.44). Whorl profile at 25 mm dm weakly depressed (ww/ wh ~0.70); coiling rate low (WER ~1.70). Venter acute with raised keel, umbilical margin rounded. Sculpture with very shallow, rounded folds with nearly linear course.

Material examined

Holotype

GERMANY • Rhenish Mountains, Oberrödinghausen, railway cutting; Hangenberg Limestone, bed 3b; Vöhringer Coll.; illustrated by Vöhringer (1960: pl. 6 fig. 7) and Korn (1994: text-fig. 70f); re-illustrated here in Fig. 115B ; GPIT-PV-64011.

Description

Holotype GPIT-PV-64011 is a specimen with 24 mm diameter embedded in a piece of limestone. The conch shows the last five whorls ( Fig. 115B ). The outer appearance is serpenticonic with a largely smooth shell surface. The conch is very slender and evolute (ww/dm = 0.22; uw/dm = 0.45) with a galeate whorl profile, which tapers sharply at the venter and has an attached, crest-like shell keel. On the last whorl, radial concave folds appear on the flank; they are most evident on the outer half of the flank. Some spiral lines are formed on the middle of the flank.

Remarks

Rodingites carinatus gen. et comb. nov. has the most prominent keel of all ammonoid species known so far from the early Tournaisian. The species is distinguished from Rodingites planissimus gen. et comb. nov. by the absence of the coarse ribs, which in Rodingites carinatus are only developed as very low folds.

Figures

Fig. 115. Pseudarietitinae from the Oberrödinghausen railway cutting, all Vöhringer Coll. A. Rodingites planissimus (Vöhringer, 1960), holotype GPIT-PV-63962 from bed 3a. B. Rodingites carinatus (Vöhringer, 1960), holotype GPIT-PV-64011 from bed 3b. C. Pseudarietites serratus Vöhringer, 1960, holotype GPIT-PV-63964 from bed 1. Scale bar units =1 mm.