Paralytoceras crispum ( Tietze, 1870 )

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 : 190-191

Paralytoceras crispum ( Tietze, 1870)

Fig. 116A

Clymenia crispa Tietze, 1869: 36 [nomen nudum].

Clymenia crispa – Tietze 1870: 135, pl. 16 fig. 12.

Sporadoceras (Paralytoceras) crispum – Frech 1902: 83, pl. 3 fig. 14.

Paralytoceras crispum – Schindewolf 1923: 397, text-fig. 11e. — Weyer 1965: 452, pl. 6 figs 2–4, text-fig. 2. — Dzik 1997: 109, text-fig. 29h. — Kullmann 2009: text-fig. 5.3.

Pseudarietites crispus – Ruan 1981: 92, pl. 22 figs 20–21.

Diagnosis

Species of Paralytoceras with conch reaching 60 mm diameter. Conch at 35 mm dm extremely discoidal, subevolute (ww/dm ~0.30, uw/dm ~0.40). Whorl profile at 35mm dm weakly compressed (ww/wh ~0.80); coiling rate moderate (WER ~1.95). Venter narrowly rounded with separate keel, umbilical margin rounded. Ornament with about 100 sharp, crenulated riblets with concave course on half a volution.

Material examined

Holotype

POLAND • Silesia, Dzikowiec ( Ebersdorf ); Gattendorfia Limestone ; Tietze Coll.; illustrated by Tietze (1870: pl. 16 fig. 12), Frech (1902: pl. 3 fig. 14), Weyer (1965: pl. 6 fig. 2), Dzik (1997: text-fig. 29h) and Kullmann (2009: text-fig. 5.3); MB.C.4692 .

Additional material

GERMANY • 1 specimen; Rhenish Mountains , Oberrödinghausen , railway cutting ; Hangenberg Limestone; Schmidt 1921 Coll .; BGR X1280 • 1 specimen; Rhenish Mountains , Oberrödinghausen, railway cutting ; Hangenberg Limestone, bed 2; Vöhringer Coll.; MB.C.31223 • 1 specimen; Rhenish Mountains , Oberrödinghausen , railway cutting ; Hangenberg Limestone, bed 3c1; Weyer 1993–1994 Coll.; MB.C.31224 .

Description

Specimen MB.C.31223 was found in the unpublished parts of the Vöhringer collection; this so far unrecognised specimen is figured here ( Fig. 116A ). It is a fragment of a specimen with an original whorl height of about 14 mm. Its whorl profile is depressed with sinuous flanks slowly approaching the acute venter. The specimen shows sharp riblets, which originate from densely spaced collar-like structures. They extend in a shallow curve in forward direction across the flanks and end at the raised ventral keel. Near the venter, the riblets have a width of 0.6 mm, similar or identical with the width of the interspaces between the riblets. The entire flank bears spiral lines; these are much weaker than the riblets and occur between as well as on top of the riblets.

Remarks

Paralytoceras crispum differs from the other species of the genus in the wider umbilicus.

Figures

Fig. 116. Paralytoceras from the Oberrödinghausen railway cutting. A. Paralytoceras crispum (Tietze, 1870), specimen MB.C.31223 (Vöhringer Coll.) from bed 2. B. Paralytoceras sp. 1, specimen MB.C.31225 (Weyer 1993–1994 Coll.) from bed 3d1.C. Paralytoceras (?) sp. 2, specimen MB.C.31227 (Weyer 1993–1994 Coll.) from bed 3d1b. Scale bar units =1 mm.