Zospeum constrictum 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 : 40-42

Zospeum constrictum Jochum & Ruthensteiner sp. nov.

urn:lsid:zoobank.org:act:350FE557-2298-40E7-A194-737D62B4303E

Figs 13–14

Diagnosis

Shell ca 1.4 mm, conical with 5½ irregularly coiled and partially flattened whorls, with ca ⅔ of the last whorl compressed under the penultimate whorl and expanding again at last quarter as it approaches the aperture; entire peristome widely reflected; peristome notch pronounced; columella centrally aligned, smooth with irregularities; no lamella; last ¼ whorl coils high up shell on ventral side with basal palatal lip almost horizontally aligned.

Etymology

This species is named for the tightly compressed coiling and tightening (constricting) of the last whorl placing it partially underneath the penultimate whorl (seen best from apical perspective).

Type material

Holotype

CROATIA • ( Figs 13A , 14A–F ); “Dalmatien Ostfuss des Biokovogebirge, Grotte bei Turija com. Kuščer” [Dalmatia, eastern foot of the Biokovo mountains , cave by Turija communicated by Kuščer]; [Brikinjava špilja]; [43.3452° N, 17.0971° E]; NHMW Mol.Coll. Edlauer 16.693.

Paratypes

CROATIA • 3 specs ( Figs 13B–D , 14G–L ); same collection data as for holotype; NHMW Mol.Coll. Edlauer 16.693 .

Description

MEASUREMENTS. Holotype: sh: 1.308 mm; sw: 1.051 mm; ah: 0.702 mm; aw: 0.623 mm; hlw: 0.938 mm; SA: 59.24 deg. Paratypes (N = 3): sh: 1.305 –1.537 mm; sw: 0.966 –1.055 mm; ah: 0.620 –0.680 mm; aw: 0.540 –0.689 mm; hlw: 0.769 –0.912 mm; SA: 57.56–76.14 deg.

Shell ca 1.4 mm, conical, with 5½ irregularly coiled convex and partially flattened whorls; opaque; aperture ovate; teleoconch sculpture with intervals of irregular blunt growth lines and weak radial banding; ⅔ of the last whorl compressed under the penultimate whorl and expanding again at last quarter as it approaches the aperture; peristome entirely reflected; aperture higher than wide; peristome thickly callused on parietal shield and on basal columellar side, columellar side roundish and slightly expanded; parietal shield straight with pronounced notch at upper parietal and palatal junction; height of last whorl greater than half of shell height; upper rim of peristome recedes ca 1 / 7 the width of the penultimate whorl (aperture facing left); last part of body whorl widens towards the aperture (aperture facing left) such that the spire appears to be sinking into the body whorl; columella centrally aligned, moderately thick, either smooth with bumpy irregularities and/or with a partial lamella positioned above mid-section of columella; ventral side swollen with shallow umbilical depression; columellar side of peristome positioned directly above umbilical depression with final coiling of last whorl high up shell on ventral side with peristome base almost horizontally aligned due to minimal basal reflection ( Fig. 14F, L ); alignment of last 1 / 5 whorl is not compact.

Distribution

This species is only known from its type locality cave, Brikinjava špilja in the Biokovo mountains of Croatia.

Remarks

This species is most similar to Z. tortuosum Jochum & Ruthensteiner sp. nov., Z. dubokidoense Jochum & Ruthensteiner sp. nov., Z. njunjicae Jochum, Schilthuizen & Ruthensteiner sp. nov. and Z. simplex in that the towering spire projects above the body whorl, causing the body whorl to almost disappear underneath the right side of the penultimate whorl before the aperture when studied in apical view ( Fig. 14C, I ). It differs from these species in that the penultimate whorl extends beyond the upper righthand side of the body whorl such that it disappears under the spire while the last part of coiling extends beyond the shell spire causing the peristome to conspicuously flare out from beneath it. In Z. tortuosum , Z. dubokidoense and Z. simplex , the body whorl and peristome tightly conform to the contour of the shell spire.

Figures

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. 14. 3D visualizations of Micro-CT data of Zospeum constrictum Jochum & Ruthensteiner sp. nov. (NHMW Mol.Coll.Edlauer 16.693). A–F. Holotype. A. Aperture and dorsal views. B. Aperture facing right view. C. Apical view showing upper right side of final whorl tucked underneath spire. D. Dorsal view. E. Aperture facing left view. F. Ventral view. G–L. Paratype (Fig. 13B). G. Aperture view. H. Aperture facing right view. I. Apical view showing upper right side of final whorl tucked underneath spire. J. Dorsal view. K. Aperture facing left view. L. Ventral view.