Zospeum troglobalcanicum Absolon, 1916

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 : 22-24

Zospeum troglobalcanicum Absolon, 1916

Figs 2 , 3A , 4A–F , 7A–C , 8A–F

Zospeum troglobalcanicum – Absolon 1916a: 15: 242 –309. — Absolon 1916b: 33 (48): 586 [Benetina Pećina, a cave above Zatokou Slanskou = Zatoka Slanska?? by Grebci].

Zospeum troglobalcanicum – Maier in Gittenberger 1975: 27.

Zospeum troglobalcanicum – Inäbnit et al. 2019: 160, fig. 7u.

Diagnosis

Shell ca 1.4 mm with conical form, 5¼ regularly coiled irregularly formed whorls, no aperture dentition; peristome with notch at upper parietal and palatal junction, basal columellar side thickly callused entering into shell; columella centrally aligned, moderately thick, swollen at base; internal lamella weak and tightly positioned on the columella directly under penultimate whorl.

Lectotype designation and rationale

We conclude that this shell, bearing the label notation “...lg Absolon” ( Fig. 3A ), is the only known syntype of Z. troglobalcanicum and thus, designate it here as the lectotype. The purpose of this lectotype designation is the fixation of a taxon name to a specific morphology and to stabilize nomenclature.

Type material

Lectotype (here designated)

BOSNIA AND HERZEGOVINA • “Benetina pećina ober Slano Südostherzegovina lg Absolon” [ Benetina pećina above Slano SE Herzegovina leg. Absolon]; [42.8105° N, 17.9142° E]; Absolon leg.; NHMW Mol.Coll. Edlauer 32.749.

Other material examined

MONTENEGRO • 3 specs; Cetinje [Dobrsko Selo], Lipa, Lipska pećina ; [42.3668° N, 18.9531° E]; Jul. 1975; F. Velkovrh leg.; MCSMNH-PMSL-Moll. -FVelkovrh 29603 (CT imaged) • 37 specs; same collection data as for preceding; MCSMNH-PMSL-Moll. - FVelkovrh 29603 .

Description

MEASUREMENTS. MCSMNH-PMSL-Moll.-FVelkovrh 29603 (N = 3): sh: 1.320 –1.428 mm, sw: 0.960 – 1.071 mm; ah: 0.543 –0.630 mm; aw: 0.571 –0.666 mm; hlw: 0.794 –0.879 mm; SA: 60.30–73.45 deg.

Lectotype: sh: 1.398 mm; sw: 1.007 mm; ah: 0.605 mm; aw: 0.640 mm; hlw: 0.886 mm; SA: 67.50 deg.; number of whorls: 5¼.

Shell with average height ca 1.38 mm, conical, with 5¼ convex whorls, regularly coiled, more or less irregularly shouldered, irregularly formed at the junction of the suture and the next whorl; teleoconch sculpture of thick irregular and blunt growth lines, sometimes crossed by weak radial banding (seen in fresh individuals), some distinct axial ribbing present for a short distance immediately behind palatal lip; height of last whorl slightly less than half of shell height; aperture reniform, peristome somewhat wider than high, columellar side oblique and angular with a thickened, long, straight parietal callus (shield), palatal rim unevenly thickened; basal columellar side of peristome slightly oblique and callused, callus extends deep into shell, basal columellar side forms a wall inside shell; degree of notch indentation at upper parietal and palatal junction variable; no aperture dentition; columellar and palatal-basal lip narrowly reflected; with aperture facing left, upper rim of peristome is indented 1 / 5 the width of the penultimate whorl; pronounced umbilical depression; in ventral perspective, the columellar side of the peristome arches over and is positioned to the right of and oblique to the umbilical depression, extending well beyond it, some puckering is present around the depression, alignment of last ¼ whorl not compact; columella centrally aligned, moderately thick, swollen at the base; internal lamella is a weak fold tightly positioned on the columella directly under penultimate whorl.

Distribution

This species is known from two caves within ca 80 km from each other in southern Bosnia and Herzegovina and western Montenegro.

Remarks

The shell of the lectotype bears an angular crack at the suture junction of the penultimate whorl and the body whorl (frontal view), extending almost midway onto the body whorl ( Figs 2 , 4A ). On the dorsal side, a short crack begins at the junction of the suture of the fourth whorl and the penultimate whorl, descending ⅓ the height of the penultimate whorl ( Fig. 4D ).

Absolon (1916a) wrote in his Balkan expedition notes about finding Z. troglobalcanicum and considerations he had in naming this species. These two paragraphs are the only record of a shell description originally written in Czech (translated by M. Leinfelder into German 2019 and by AJ into English). A single photograph of the 13 syntype shells with a short caption of the locality, “Benetina pećina“ was provided in a second publication ( Absolon 1916b).

Original (translated) description of Zospeum troglobalcanicum ( Absolon 1916a) :

“My most interesting find during 1914, was the discovery of the first Balkan Zospeum “troglobalcanicum ” n. sp., which I found in the cave “Benetina Pecina” over the bay of “Slanka” (loc. ca 122 [on Absolon’s map by Grebci], still in Herzegovina). According to Clessin’s keys and Kobelt’s iconography, it would be easy for me to identify my Zospeum , like the other Zospeum , that has absolutely no dentition in its shell, to be ancestral to Z. amoenum . To be sure, I sent a cotype to Herrn Dr. F. Baborov for review and [who] confirmed my find as I expected Zospea to exist in the western Balkan. The fauna in Herzegovina generally has many special characteristics in common with the Croatian-Kranj [Slovenian] region, albeit specifically modified, for example, certain Myriapoda, Stalita, Titanethes, Monolistra, Troglocaris; the border seems to be the Valley of the Neretva.

The collection activity of other colleagues has contributed considerably to this collection (Aspasita Hauffeni, kranj-istrien-croatian Zospea, Auritus erika etc.) and through exchanges, I have received many valuable and unique morphs, some of which I received on loan (Museum Wien, Stuttgart = Clessin type (Vitrelly 4), Croatian Zoological Museum Zagreb, L. Kuščer (Triest), Dr. R. Schröder (Munich) and others. An extensive investigation of all the known material up to now has hereby been undertaken, including Eastern European troglobitic malacofauna. With much help from my wife, I have processed 95 morphs (in literature) using new methods from the microphotographic atlas consisting of about 500 images. This requires a separate and comprehensive report.”

In sync with Absolon’s identification quandary above, H.C. Maier tucked his handwritten considerations into vials of shells at the NHMW via specimen assessment notes, stamped “revid Maier, 1977” ( Figs 3 , 9 , 12–13 , 15 ). We remark that the author of these notes is Heinz Christian Maier, whose unpublished doctoral thesis on Zospeum was realized in 1982 and accessed for this work.

Figures

Fig. 2. 3D visualizations of Micro-CT data of the lectotype of Zospeum troglobalcanicum Absolon, 1916 (NHMW Moll.Coll.Edlauer 32.749) with shell parts and terms indicated. A. Measurements include shell height (sh), shell width (sw), aperture height (ah), aperture width (aw), height of last whorl (hlw) and spire angle (SA). B. Internal view showing columella (co), lamella (la), peristome (pe) and penultimate whorl (pw). C. Apical view showing protoconch (pr), teleoconch (te) and peristome (pe). D. Ventral view showing peristome configuration (pe) parietal shield (ps) and umbilicus (um).

Fig. 3. Light microscopic images of shells from the caves Benetina pećina (SE Bosnia and Herzegovina) and Cetinska pećina (Montenegro) with specimen labels. A. Zospeum troglobalcanicum Absolon, 1916, lectotype (NHMW Moll.Coll.Edlauer 32.749) from Benetina pećina. B–C. Zospeum tortuosum Jochum & Ruthensteiner sp. nov., paratypes (MCSMNH-PMSL-Moll.-FVelkovrh 34099[spm2-3]) from Cetinska pećina. D. Zospeum tortuosum Jochum & Ruthensteiner sp. nov., holotype (MCSMNH- PMSL-Moll.-FVelkovrh 34099[spm1]) from Cetinska pećina. E. Deformed shell (MCSMNH-PMSL- Moll.-FVelkovrh 34099[spm4]) from Cetinska pećina.

Fig. 4. 3D visualizations using Micro-CT data of shells from the caves Benetina pećina (SE Bosnia and Herzegovina) and Cetinska pećina (Montenegro). A–F. Zospeum troglobalcanicum Absolon, 1916, lectotype (NHMW Moll.Coll.Edlauer 32.749). A. Aperture view. B. Aperture facing right view. C. Apical view. D. Dorsal view. E. Aperture facing left view. F. Ventral view showing umbilical depression. G–L. Zospeum tortuosum Jochum & Ruthensteiner sp. nov., holotype (MCSMNH-PMSL- Moll.-FVelkovrh 34099[spm1]). G. Aperture view. H. Aperture facing right view. I. Apical view. J. Dorsal view. K. Aperture facing left view. L. Ventral view showing callused peristome positioned mostly on top of umbilicus.

Fig. 7. Lightmicroscopic images of shells from the caves Lipska pećina and Duboki do (Montenegro) with specimen labels. A–C. Zospeum troglobalcanicum Absolon, 1916 (MCSMNH-PMSL-Moll.-FVelkovrh 29603). D–F. Zospeum dubokidoense Jochum & Ruthensteiner sp. nov. D. Holotype (MCSMNH- PMSL-Moll.-FVelkovrh 30360[spm1]). E–F. Paratypes, Duboki do, Montenegro (MCSMNH-PMSL- Moll.-FVelkovrh 30360[spm2-3]).

Fig. 8. 3D visualizations of Micro-CT data of shells from the caves Lipska pećina and Duboki do (Montenegro). A–F. Zospeum troglobalcanicum Absolon, 1916 (MCSMNH-PMSL-Moll.-FVelkovrh 29603) (Fig. 7A). A. Aperture view. B. Aperture facing right view. C. Apical view. D. Dorsal view. E. Aperture facing left view. F. Ventral view showing reduced umbilical depression. G–L. Zospeum dubokidoense Jochum & Ruthensteiner sp. nov., holotype (MCSMNH-PMSL-Moll.-FVelkovrh 30360[spm1]). G. Aperture view. H. Aperture facing right view. I. Apical view. J. Dorsal view. K. Aperture facing left view. L. Ventral view showing no umbilical depression.

Fig. 9. Zospeum amplioscutum Jochum & Ruthensteiner sp. nov., (NHMW Mol.Coll.Edlauer 19.069) with sample labels. A. Light microscopic images of paratype (NHMW Mol.Coll.Edlauer 19.069), apertural and dorsal views.B. Light microscopic images of holotype (NHMW Mol.Coll.Edlauer 19.069), aperture and dorsal views. C–H. 3D visualizations of X-ray Micro-CT data of holotype (NHMW Mol. Coll.Edlauer 19.069). C. Aperture view. D. Aperture facing right view. E. Apical view. F. Dorsal view. G. Aperture facing left view. H. Ventral view showing coiling projecting high up on shell and peristome oblique to umbilicus.

Fig. 12. Zospeum neuberti Jochum & Ruthensteiner sp. nov. (NHMW Mol.Coll.Edlauer 32006). A–B. Light microscopic images of paratypes showing aperture and dorsal views and collection labels. C. Light microscopic images of holotype showing aperture and dorsal views. D–I. 3D visualizations of Micro-CT data of holotype. D. Aperture view. E. Aperture facing right view showing smooth columella. F. Apical view.G. Dorsal view showing smooth columella. H. Aperture facing left view. I. Ventral view.

Fig. 13. Light microscopic images of Zospeum constrictum Jochum & Ruthensteiner sp. nov. (NHMW Mol.Coll.Edlauer 16.693) and collection labels.A. Holotype, aperture, and dorsal views.B–D. Paratypes, aperture and dorsal views.

Fig. 15. Zospeum biokovoense Jochum & Ruthensteiner sp. nov. (NHMW Mol.Coll.Edlauer 16.390). A–B. Light microscopic images showing aperture and dorsal views and collection labels. A. Juvenile shell. B. Holotype. C–H. 3D visualizations of Micro-CT data of holotype. C. Aperture view showing gnarled deformation of the columella. D. Aperture facing right view showing fat columella and lamella. E. Apical view. F. Dorsal view showing lopsided spire and incomplete lamella on top of fat columella. G. Aperture facing left view. H. Ventral view showing puckered umbilical depression.