Zospeum njegusiense Jochum & Ruthensteiner, 2024

Jochum, Adrienne, Michalik, Peter, Inäbnit, Thomas, Kneubühler, Jeannette, Slapnik, Rajko, Vrabec, Marko, Schilthuizen, Menno & Ruthensteiner, Bernhard, 2024, 3 D X-ray microscopy (Micro-CT) and SEM reveal Zospeum troglobalcanicum Absolon, 1916 and allied species from the Western Balkans (Ellobioidea: Carychiidae), European Journal of Taxonomy 926, pp. 1-62 : 47-48

Zospeum njegusiense Jochum & Ruthensteiner sp. nov.

urn:lsid:zoobank.org:act:882B9D99-6028-4DC7-B9A0-82033E474B39

Fig. 17

Diagnosis

Shell conical with 5¼ flatly convex whorls; aperture reniform; penultimate whorl over ½ height of body whorl; columella slender with a distinctly sculpted and broad lamellar band obliquely projecting ca ⅓ beyond the width of the slender columella; a second, barely visible low lamella is present at mid-section of the columella. Suture deep.

Etymology

This species is named after its type locality Njeguši, Montenegro.

Type material

Holotype (SEM sample)

MONTENEGRO • ( Fig. 17A, D ); Njeguši, St John’s cave ; 42.4307° N, 18.8115° E, 915 m a.s.l.; ca - 85 m vertical depth below the cave entrance; 5 Aug. 2021; László Dányi & Nikolett Ujhegyi leg.; NMBE 572639 (ex AJC 2483).

Paratypes (SEM sample)

MONTENEGRO • ( Fig. 17B–C, E ); 2 specs (broken shells); same collection data as for holotype; NMBE 578378 (ex AJC 2483) .

Description

MEASUREMENTS. Holotype: sh: 1.37 mm; sw: 0.96 mm; ah: 0.61 mm; aw: 0.61 mm; 0.63; hlw: 0.88 mm; SA: 68.04 deg.

Shell subfossil, eroded; conical with 5¼ flatly convex whorls; aperture reniform; penultimate whorl over ½ height of body whorl; teleoconch smooth with intermittent impressed striations on the body whorl; suture deep; parietal shield well defined, thick, long, and angular, curved at max. whorl convexity; peristome notch prominent at upper junction with parietal shield; smooth, impressed irregular ribbing behind peristome; columella slender with a distinctly sculpted and broad lamellar band obliquely projecting ca ⅓ beyond the width of the slender columella; a second, barely visible low ripple is present at mid-section of the columella.

Distribution

This species is only known from the type locality, St John’s cave in Njeguši, Montenegro.

Remarks

The species differs from Z. kolbae Jochum, Inäbnit, Kneubühler & Ruthensteiner sp. nov. in its uniformly conical shell form and its narrow, reniform apertural shape. Though the straight and robust columella is reminiscent of that in Z. njunjicae Jochum, Schilthuizen & Ruthensteiner sp. nov., the pronounced configuration of the lamella differentiates significantly from the weak low lamella of that species (as seen in all its Micro-CT perspectives) except perhaps the dorsal view, which is different altogether in bearing a distinctive lamellar bulge and a secondary low lamella above the tortional formation at the base of the columella. Though the shell is eroded, it shares no whorl size dimensions nor body whorl or penultimate whorl shape with the unidentified and unassessed morphospecies, Zospeum sp. 1 (NMBE 577052–577053) ( Fig. 16C–E ) also found in St John’s cave.

Figures

Fig. 17. Z. njegusiense Jochum & Ruthensteiner sp. nov., Scanning Electron Microscopy images. A. Holotype (NMBE 572639), aperture view showing subfossil shell with superficial erosion of shell layer. B. Paratype (NMBE 578378), aperture view showing close up of lamellar band on columella (Fig. C). C. Paratype (NMBE 578378), aperture view showing damaged shell and columella. D. Close up view of holotype (NMBE 572639), showing body whorl with low, irregular growth lines. E. Paratype (NMBE 578378), protoconch.

Fig. 16. Light microscopic images of full-bodied Zospeum Bourguignat, 1856 from Njeguši, St John’s cave. A–B. Zospeum kolbae Jochum, Inäbnit, Kneubühler & Ruthensteiner sp. nov. (NMBE 571122– 571123), individuals assessed by DNA sequencing with sigmoid intestine showing through shells (shells were destroyed post imaging for tissue extraction). A. Holotype (NMBE 571122), shell of aliquot, aperture, and aperture facing left view. B. Paratype (NMBE 571123), shell of aliquot, aperture, and aperture facing left view. C. Undescribed Zospeum sp. 1 (NMBE 577052) showing all perspectives. D–E. Undescribed Zospeum sp. 1 (NMBE 577053/2) showing all perspectives.