Zospeum njunjicae Jochum, Schilthuizen & 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 : 36-38

Zospeum njunjicae Jochum, Schilthuizen & Ruthensteiner sp. nov.

urn:lsid:zoobank.org:act:F762D981-D8FB-4EE7-BB0F-489E3D596A04

Fig. 11 , 22A–B

Diagnosis

The smallest species of southern Balkan Zospeum , ca 1.2 mm, conical with 5 regularly coiled irregularly formed whorls; protoconch askew; peristome heavily callused on basal columellar side with a low, blunt, more or less conspicuous denticle some distance inside; columella centrally aligned, moderately thick, swollen at base; low lamella; well-defined umbilical depression.

Etymology

This species is dedicated to the biospeleologist and collector, Iva Njunjić.

Type material

Holotype

MONTENEGRO • ( Fig. 11C–I ); Virpazar, Gornja Seoca , Golubova pećina ; 42.2093° N, 19.1306° E; 26 Jun. 2018; M. Schilthuizen and I. Njunjić leg.; in cave entrance; NMBE 572617 .

Paratypes

MONTENEGRO • 2 specs; same collection data as for holotype; NMBE 572616 • 2 specs; same collection data as for holotype; SMF 349426 • 2 specs; same collection data as for holotype; NHMWMO-113651 • 3 specs; same collection data as for holotype; TxEx-DU0018 .

Description

MEASUREMENTS. Holotype: sh: 1.271 mm; sw: 0.914 mm; ah: 0.560 mm; aw: 0.578 mm; hlw: 0.811 mm; SA: 69.69 deg. Paratypes (N = 2): sh: 1.214 –1.248 mm; sw: 0.944 –0.947 mm; ah: 0.578 –0.588 mm; aw: 0.507 –0.524 mm; hlw: 0.764 –0.790 mm; SA: 71.38–71.83 deg.; NMBE 572616.

Shell minute, ca 1.2 mm, conical, with 5 regularly coiled convex whorls; transparent when fresh, opaque when older; protoconch leans slightly left (frontal view); aperture reniform; teleoconch sculpture with few irregular and occasional course growth lines, last whorl weakly crossed by radial banding; some weak axial ribbing present immediately behind palatal lip; palatal rim narrowly reflected; peristome thickly callused, notch indentation at upper parietal and palatal junction pronounced, upper palatal side thin and expanded, columellar side oblique and angular with a low, blunt, more or less conspicuous denticle inside; parietal shield thickly callused, long and straight, extending beyond half of height of last whorl; last whorl height about half of shell height ( Fig. 11E ), last whorl tightly coiled and almost disappearing under spire at last ⅓ of coiling (apical view); upper rim of peristome recedes ca 1/6 the width of the penultimate whorl (aperture facing left); columella centrally aligned, moderately thick ( Fig. 11E ), lamella loosely coiled on columella under penultimate whorl; umbilical depression callused, puckered; columellar side of peristome arches high over with curvature of whorl on top of umbilical depression, alignment of last 1/4 whorl is not compact.

Distribution

This species is only known from its type locality cave, Golubova pećina in southwestern Montenegro.

Remarks

This species differs from all others in that it demonstrates the smallest shells of the Southern Balkan region so far. The columella is more robust than that of Z. troglobalcanicum and the lamella comprises a low bulge rather than an incomplete thread atop of the columella directly under the penultimate whorl as in Z. troglobalcanicum . The columella of this species is also unevenly contoured with a few low humps due to the tight twisting of the inner coiling.

Figures

Fig. 11. Zospeum njunjicae Jochum, Schilthuizen & Ruthensteiner sp. nov. A–B. Light microscopic images of paratypes (NMBE 572616) showing aperture and dorsal views. C. Light microscopic images of holotype (NMBE 572617) showing aperture and dorsal views. D–I. 3D visualizations of X-ray micro- CT data of holotype (NMBE 572617). D. Aperture view. E. Aperture facing right view showing well defined lamella. F. Apical view. G. Dorsal view. H. Aperture facing left view. I. Ventral view.

Fig. 22. Sites of localities and collections. A. Site of type locality of Zospeum njunjicae Jochum, Schilthuizen & Ruthensteiner sp. nov., Golubova pećina, Gornja Seoca, Montenegro. Credit: I. Njunjić. B. Collection site within St John’s cave, type locality of Z. kolbae Jochum, Inäbnit, Kneubühler & Ruthensteiner sp. nov. and Z. njegusiense Jochum & Ruthensteiner sp. nov., Njeguši, Montenegro (42.4307° N, 18.8115° E) with speleologist, P. Kunisch. Credit: Péter Lenkei. C. Entrance to Golubova pećina (42.2093° N, 19.1306° E), Gornja Seoca, Montenegro. Credit: I. Njunjić.