Curtoceras meyeri, Aubrechtová & Korn, 2025

Aubrechtová, Martina & Korn, Dieter, 2025, The coiled Middle Ordovician cephalopod genera Trocholites and Curtoceras (Tarphyceratida) from Baltoscandia and north-central Europe, European Journal of Taxonomy 982, pp. 1-78 : 69-70

publication ID	https://doi.org/10.5852/ejt.2025.982.2843
publication LSID	lsid:zoobank.org:pub:00EDB7C3-98B6-4FF6-93C3-2B2DCF8FA3A9
DOI	https://doi.org/10.5281/zenodo.15096440
persistent identifier	https://treatment.plazi.org/id/03AD87B1-DD4D-4223-311B-9E3D95A7FC2C
treatment provided by	Plazi
scientific name	Curtoceras meyeri
status	sp. nov.

Treatment

Curtoceras meyeri sp. nov.

urn:lsid:zoobank.org:act:69962EDA-B814-4DA9-84FA-8592B6E57609

Fig. 36 View Fig ; Table 24 View Table 24

Diagnosis

Species of the genus Curtoceras with an adult conch exceeding 40 mm in diameter. At 40 mm diameter, the conch is discoidal (CWI ~ 0.45) and subevolute (UWI ~ 0.45) with high coiling rate (WER ~ 2.20); whorl profile with rounded flanks and venter, weakly depressed (WWI ~ 1.35) and weakly embracing (IZR = 0.05). Shell surface with lirae. Phragmocone chambers short (RCL ~ 0.10). Suture line almost straight or with a very shallow lateral lobe and a ventral saddle. Siphuncle subdorsal (RSP ~ 0.85) and narrow (RSH ~ 0.15).

Etymology

Named after Günter Meyer (Bernau), who donated a well-preserved Curtoceras specimen to be studied herein.

Type material

Holotype

GERMANY • unspecified locality in northern Germany ; ?Lasnamägi Regional Stage ; illustrated in Fig. 36A View Fig ; MB.C. 11550 .

Description

Holotype MB.C.11550 ( Fig. 36A View Fig ) is a subadult conch with 41 mm diameter and has almost three whorls preserved; the body chamber is missing. In the last half whorl, the conch is discoidal ( CWI = 0.46) and subevolute ( UWI = 0.44); the coiling rate is high ( WER = 2.20). The whorl profile has broadly rounded flanks and venter; it is weakly depressed ( WWI = 1.35) and weakly embracing ( IZR = 0.04) ( Fig. 36B View Fig ). The shell ornament is preserved only in a small area on the venter, where it consists of lirae that extend into a ventral sinus. The phragmocone chambers are short ( RCL = 0.11). The suture line is almost straight or possesses a very shallow lateral lobe; however, on the venter of at least the last whorl, the suture line extends into a progressively pronounced saddle. The siphuncle is subdorsal in position ( RSP = 0.85) and about 0.16 in relative diameter ( RSH).

Remarks

Curtoceras meyeri sp. nov. differs from other species of Curtoceras in the increasingly pronounced external saddle of the suture line starting with the third whorl, combined with the comparably high WWI and comparatively short phragmocone chambers.