Zospeum tortuosum Jochum & Michalik & Inäbnit & Kneubühler & Slapnik & Vrabec & Schilthuizen & Ruthensteiner 2024, sp. nov.
Creators: name: Jochum, Adrienne
name: Michalik, Peter
name: Inäbnit, Thomas
name: Kneubühler, Jeannette
name: Slapnik, Rajko
name: Vrabec, Marko
name: Schilthuizen, Menno
name: Ruthensteiner, Bernhard
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Ellobiida
Ellobiidae
Zospeum
Zospeum tortuosum

description: Zospeum tortuosum Jochum & Ruthensteiner sp. nov.
urn:lsid:zoobank.org:act: BDD1308E-7D4C-447C-8009-E60D76AB38D2
Figs 3B–D, 4G–L
Diagnosis
Shell ca 1.4 mm, conical or elongate-conical with ca 5¼ regularly coiled, slightly shouldered whorls; last coiling of shell twists a fraction beyond the frontal plane ca ⅛ the width of body whorl; columella slanted and not centrally aligned; no lamella; ventral side swollen with columellar side of peristome heavily callused on top of and plugging umbilicus.
Etymology
This species is named after the characteristic ⅛ additional turn of the last whorl. Due to the twisted offcenter alignment of the columella, the last whorl and the aperture are slightly turned to the left.
Type material
Holotype
MONTENEGRO • “Cetinska pećina, Cetinje, vhod; Mtg.” [Cetinska cave, Cetinje, entrance; Montenegro]; [42.3886°N, 18.9208°E]; Sep. 1976; F. Velkovrh leg.; MCSMNH-PMSL-Moll. - FVelkovrh 34099[spm1].
Paratypes
MONTENEGRO • 2 specs; same collection data as for holotype; MCSMNH-PMSL-Moll. - FVelkovrh 34099[spm2-3].
Description
MEASUREMENTS. Holotype: sh: 1.435 mm; sw: 0.944 mm; ah: 0.515 mm; aw: 0.511 mm; hlw: 0.841 mm; SA: 57.93 deg. Paratypes (N = 2): sh: 1.349–1.43 mm; sw: 0.951 –0.972 mm; ah: 0.548 –0.559 mm; aw: 0.575 –0.609 mm; hlw: 0.827 –0.844 mm; SA: 61.20–65.16 deg.
Shell conical, height 1.35–1.44 mm with 5¼ convex whorls. Whorls unevenly formed and slightly shouldered; protoconch bulbous; spire angle narrow; last whorl coils beyond the frontal plane ca ⅛width of body whorl, right side sometimes almost disappears under spire in apical view; aperture reniform, somewhat narrower than high, no aperture dentition, columellar side straight, not oblique, thickly and irregularly callused; peristome notch at upper parietal and palatal junction; parietal callus (shield) thick, long and straight; palatal rim uniformly thickened to halfway the height of peristome, palatal-basal lip thins to a ridgelike edge, reflected; suture moderately deep; teleoconch generally smooth with occasional surface irregularity; last whorl shows occasional, irregular blunt growth lines at suture with penultimate whorl, extending downwards to ca ⅓ the height of the last whorl; weak radial banding on last whorl (seen in fresh individuals); some ribbing and irregular growth lines immediately behind palatal lip; light irregular ribbing on last whorl; height of last whorl greater than half of shell height; upper peristome rim almost flush with left side of penultimate whorl (in aperture facing left view); columella unevenly formed, moderately thick, not centrally aligned, tightly twisted, abapically attenuated, swollen at base; no umbilical depression is present; umbilicus thickly callused at junction of peristome and base of columella, columellar side of peristome positioned on top of callused umbilicus, base swollen with some puckering; alignment of last ¼ whorl compact.
Distribution
This species is only known from its type locality, Cetinska pećina, Cetinje in western Montenegro.
Remarks
The species is most similar in shell form and dimensions to Z. troglobalcanicum. It differs mostly by the extra turning of the final whorl and the associated sideways twisting of the columella. It differs from Z. troglobalcanicum in that it does not bear a conspicuous threadlike lamella on its twisted columella.
Deformed shell (Figs 3E, 5)
A deformed second shell, (MCSMNH-PMSL-Moll.-FVelkovrh 34099[spm4]), similar to that of Zospeum tortuosum Jochum & Ruthensteiner sp. nov. and found in the same lot from Cetinska pećina, is additionally described and considered in chronological context with the image figures of Zospeum tortuosum.
Data of the deformed shell
The species data are: “Cetinska pećina, Cetinje, vhod; Mtg.” [Cetinska cave, Cetinje, entrance; Montenegro]; [42.3886° N, 18.9208° E]; Sept. 1976; F. Velkovrh leg. MCSMNH-PMSL-Moll.- FVelkovrh 34099[spm4].
Measurements of the deformed shell
Shell: sh: 1.396 mm; sw: 0.922 mm; ah: 0.566 mm; aw: 0.590 mm; hlw: 0.836 mm; SA: 60.01 deg.
Description of the deformed shell
Shell conical, height 1.4 mm with 5¼ whorls; transparent. Whorls convex, and slightly shouldered, spire regularly coiled; suture moderately deep; aperture oriform, elliptical ovate, wider than high, interior of aperture heavily callused with wartlike growths on palatal side and in mid parietal region, giving the impression of a wart-like tooth; columellar side of peristome straight and angular; no notch at upper parietal and palatal junction; parietal callus (shield) well defined, narrow, roundish; palatal rim unevenly thin, thickening only at basal-columellar zone; palatal-basal lip thins to a ridgelike edge, narrowly reflected; teleoconch with course irregular growth lines; weak radial banding on penultimate and body whorl; course irregular growth lines present immediately behind palatal-basal lip and extending some distance from peristome rim; height of last whorl greater than half of shell height; upper peristome rim recedes 1 / 5 width of penultimate whorl (in aperture facing left view); columella oblique, moderately thick, not centrally aligned, swollen at base; incomplete callused lamella under penultimate whorl; no umbilical depression; umbilicus thickly callused at junction of peristome and base of columella, columellar side of peristome positioned on top of callused umbilicus, base swollen with some puckering; upper palatal rim not reflected (as seen from umbilical view), alignment of last ¼ whorl compact.
Remarks on the deformed shell
Although this shell has wart-like deformation in the aperture, the elliptical ovate aperture shape and the columella configuration, which is unaffected by the deformation, largely corresponds to that of Z. tortuosum Jochum & Ruthensteiner sp. nov. (MCSMNH-PMSL-Moll.-FVelkovrh 34099[spm1]) from the same cave. Though the aperture shape also resembles that of Z. dubokidoense Jochum & Ruthensteiner sp. nov. (Fig. 7D, 8G), the deformed shell shows narrower and smaller dimensions. Due to the compactness of the last quarter whorl, the straight alignment of the left side of the peristome on top of the umbilical depression and the narrowness of the parietal shield, this shell cannot be unequivocally determined as Z. tortuosum sp. nov.
description: Published as part of 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), pp. 1-62 in European Journal of Taxonomy 926 on pages 24-28, DOI: 10.5852/ejt.2024.926.2469, http://zenodo.org/record/10847806