Zospeum simplex Inaebnit , Jochum & Neubert, sp. nov.

Inaebnit, Thomas, Jochum, Adrienne, Slapnik, Raijko & Neubert, Eike, 2021, New genetic data reveals a new species of Zospeum in Bosnia (Gastropoda, Ellobioidea, Carychiinae), ZooKeys 1071, pp. 175-193 : 175

Zospeum simplex Inaebnit, Jochum & Neubert, sp. nov.

Figures 1 , 3

Type specimens.

Holotype: NMBE 568060, Jama Dobravljevac, 25.08.2019, leg. R. Slapnik & J. Valentinčič; Paratypes: NMBE 568061-568063; SMF 349425, 4 shells; RSC 3760, 6 shells; Jama Dobravljevac, 25.08.2019, leg. R. Slapnik & J. Valentinčič.

Specimens examined.

NMBE 568054, Špilja Dahna, 03.09.2009, leg. A. Schoenhoffer; NMBE 568055-568058, Jama u kamenolomu, 24.08.2019, leg. R. Slapnik & J. Valentinčič; NMBE 568059, Vranjača, 24.08.2019, leg. R. Slapnik & J. Valentinčič.

Diagnosis.

Shell usually ca. 1.3 mm in height, transparent, conical, peristome thickened, roundish, with a differentiated parietal shield, lamellae not present.

Measurements (n = 9): Shell height: 1.26-1.42 mm (mean: 1.378 ± 0.047 mm); shell width: 0.93-1.04 mm (mean: 0.976 ± 0.035 mm); aperture height: 0.54-0.67 mm (mean: 0.6 ± 0.037); aperture width: 0.54-0.65 mm (mean: 0.601 ± 0.033 mm); number of whorls: 5-5.5.

Description.

Shell conical, translucent when fresh; suture deep; aperture somewhat roundish to reniform; parietal shield clearly differentiated from the rest of the lip, straight and thin; no lamellae present.

Differing from Z. pretneri and Z. tholussum by its broader shell and the differentiated parietal shield; differs from Z. manitaense by the absence of a visible parietalis in the aperture; barely differs from Z. aff. troglobalcanicum morphologically, on average with reduced shell broadness and a slightly deeper suture (see Remarks).

Distribution.

Known from four caves (Jama Dobravljevac, Špilja Dahna, Jama u kamenolomu, Vranjača) in the municipality of Tomislavgrad in Bosnia-Herzegovina.

Etymology.

Named Zospeum simplex (= simple, unsophisticated) due to the lack of any form of shell sculpture or lamellae.

Remarks.

Difficult to separate from Z. troglobalcanicum without genetic data (which is not uncommon in Zospeum ; see Inäbnit et al. 2019). Both species have a nondescript shell without prominent shell sculpture or lamellae within the aperture. Absolon’s (1916) description of Z. troglobalcanicum consisted out of a photograph depicting multiple specimens haphazardly clustered together in various positions and a legend that established the name and type locality. The lack of a written characterisation of the species in the original description and the fact that the specimens in the photograph weren’t depicted in any standardised position makes a characterisation of the species fairly challenging (putative syntype specimen, collected by K. Absolon from the type locality, was only located very recently by AJ in Vienna (NHMW Mol.Coll.Edlauer 32.749) and couldn’t be studied yet). From the photograph in Absolon (1916), the species can be characterised as similar to Z. manitaense in shell shape, without any visible lamella in the aperture and with a comparatively large parietal shield. The larger parietal shield might serve as a distinguishing character between Z. simplex and Z. troglobalcanicum , though the illustration of a topotypic specimen in Bole (1974; fig. 3h) might indicate that this character is variable within the population. The two specimens we preliminarily assigned to Z. troglobalcanicum (Fig. 3 , NMBE 568052; Inäbnit et al. 2019: fig. 7u) only have a small parietal shield. As of now, the shell height:shell width ratio seems to be the most effective way of separating the two specimens from Z. simplex ( Z. simplex : generally higher than 1.3 (one exception); Z. aff. troglobalcanicum : below 1.3), but that might just be due to the low sample sizes. Investigation of the inner aspects of the shells will be presented in a later work.

Figures

Figure 1. Map showing the distribution of the Zospeum pretneri group and the Zospeum alpestre group (except Z. isselianum). Austrian specimens from Kruckenhauser et al. (2019) are labelled as " Z. cf. amoenum ".

Figure 3. Specimens sequenced in this study. Zospeum troglobalcanicum: NMBE 568052 & 568053 (both from Spilja Jezero); Zospeum simplex sp. nov.: NMBE 568054 (Spilja Dahna), NMBE 568055 - 568057 (Jama u kamenolomu), NMBE 568059 (Vranjaca), NMBE 568060 (Holotype, Jama Dobravljevac), NMBE 568061 - 568063 (Paratypes, Jama Dobravljevac)