Zospeum amplioscutum Jochum & Ruthensteiner sp. nov.

urn:lsid:zoobank.org:act: 870FA5D2-6A9A-43AA-A533-B25CFC89A96D

Fig. 9

Diagnosis

Shell ca 1.30–1.36 mm, conical with 5½ irregularly convex whorls; peristome thickly callused on columellar side causing it to project beyond plane of shell (ventral side view); parietal shield well defined, positioned conspicuously high on body whorl and heavily callused; columella slender (aperture facing right) (Fig. 9D) with two weak, incomplete lamellae. Last ¼ of body whorl elongate on ventral side.

Etymology

This species is named after the characteristic, large and heavily callused parietal shield.

Type material

Holotype

CROATIA • (Fig. 9B); “Adria, Insel Brać (Brazza) Bazgova jama, com. Kuščer” [Adriatic, Island of Brać, Jama Bazdovača, communication with Kuščer]; [43.2918° N, 16.6469° E]; NHMW Mol.Coll. Edlauer 19.069.

Paratype

CROATIA • 1 spec. (Fig. 9A); same collection data as for holotype; NHMW Mol.Coll. Edlauer 19.069 .

Description

MEASUREMENTS. Holotype: sh: 1.362 mm; sw: 0.966 mm; ah: 0.631 mm; aw: 0.574 mm; hlw: 0.808 mm; SA: 63.28 deg. Paratype (N = 1): sh: 1.304 mm; sw: 0.940 mm; ah: 0.608 mm; aw: 0.609 mm; hlw: 0.804 mm; SA: 63.53 deg.

Shell conical, height 1.30–1.36 mm with 5½ irregularly convex whorls bearing numerous, course irregular growth lines; aperture lunate-reniform; peristome narrow on upper palatal side, pronounced notch present at upper junction with parietal shield, lower columellar side of peristome rounded and thickly callused, causing it to project beyond plane of shell (aperture facing left), rim narrowly reflected with some low, irregular ribbing behind basal-palatal part; rim recedes ca ⅛ width of penultimate whorl; parietal shield long, angular, thickly callused, extending ⅓ to ½ the height of the body whorl, with a curved edge at point of maximum whorl convexity; columella centrally aligned, slender with hint of two weak incomplete lamellae, the first tightly positioned under the penultimate whorl, the second, a wider band loosely positioned below it, and a slight bulge at base; umbilical region callused with a shallow depression; (ventral view) columellar side of peristome positioned high, arching above and to the right of umbilical depression, alignment of last ¼ whorl elongate, not compact.

Distribution

This species is only known from its type locality, Jama Bazdovača on the Croatian Island of Brać.

Remarks

Though Z. amplioscutum Jochum & Ruthensteiner sp. nov. resembles Z. simplex, the heavily callused parietal shield and the degree of its extension onto the body whorl differs from that of this species. It is smaller, has a wider spire angle and a substantially more textured teleoconch due to the numerous, course irregular growth lines in comparison to that of Z. simplex . Zospeum simplex does not have a second lamella on the columella (aperture facing right) (Fig. 18B) but weak ripples of a potential double one (Fig. 18D) or a stronger, incomplete single one in dorsal view (Fig. 18J). The narrow columella (Fig. 9C–D) and the elongation of the last whorl further beyond the umbilical depression (ventral side) additionally differentiate Z. amplioscutum from Z. simplex .