Trocholites luna, Aubrechtová & Korn, 2025

Trocholites luna sp. nov.

urn:lsid:zoobank.org:act:0E391219-F3BE-44A3-8ECB-42526225CF54

Fig. 21 View Fig ; Table 12 View Table 12

Diagnosis

Species of the genus Trocholites with an adult conch diameter of about 50 mm. Conch in the last whorl thinly discoidal (CWI ~ 0.38) and evolute (UWI ~ 0.52) with low coiling rate (WER ~ 1.60). Whorl profile moderately depressed (WWI ~ 1.55) with rounded flanks and slightly flattened venter, weakly embracing (IZR ~ 0.14). Shell ornament with raised lirae or accumulation of lirae in the inner whorls, venter of body chamber with low, regularly spaced annuli and fine lirae. Phragmocone chambers long (RCL ~ 0.38). Suture line straight.

Etymology

From the Latin ‘ luna ʼ (nomen) = ‘the Moonʼ, referring to the shape of the relatively large conch of the holotype.

Type material

Holotype

GERMANY – Brandenburg • Oderberg; Ordovician; 1970; Krueger Coll.; illustrated in Fig. 21 View Fig ; MB.C. 32174

Description

Holotype MB.C.32174 ( Fig. 21 View Fig ) is a specimen partially embedded in the rock matrix. The conch has a diameter of 48 mm and represents the adult growth stage. It is thinly discoidal (CWI = 0.38) and evolute (UWI = 0.52) with a low coiling rate (WER = 1.60). In the last half volution, the whorl profile has continuously rounded flanks and slightly flattened venter; the whorl profile is moderately depressed (WWI = 1.56) and weakly impressed dorsally (IZR = 0.14). The body chamber is longer than half of a volution; the proximity of aperture is indicated by inconspicuous ventral flare. The ornament of the inner whorls consists of sharp raised lirae or accumulations of lirae; the venter of the terminal body chamber has low and equally spaced annuli and fine lirae. The phragmocone chambers are long (RCL = 0.38). The suture line is nearly straight, but extends with a very low saddle across the venter.

Remarks

Trocholites luna sp. nov. is similar to T. vortex sp. nov., but differs in the lower coiling rate (WER = 1.60 vs 1.80), the more slender conch (CWI = 0.38 vs 0.47), the more depressed whorl profile (WWI = 1.56 vs 1.45) and the wider umbilicus (UWI = 0.52 vs 0.45) in the adult growth stage.

The holotype of Trocholites luna sp. nov. is rather similar to the neotype of T. macrostoma with respect to conch width and umbilical width, but differs in the less depressed last whorl (WWI = 1.56 vs 1.72) and the presence of annuli on the venter of the body chamber.

The two specimens of T. vodickai sp. nov. differ from the holotype of T. luna sp. nov. in the smaller adult size (40 mm vs 50 mm); the last whorl in the former is less evolute (UWI ~ 0.46 vs 0.52) and the shell ornament in inner whorls has fine, rursiradiate lirae instead of sharply raised lirae or accumulation of lirae.