Zospeum costatum
Creators: name: Lukeneder, Petra
name: Ottner, Franz
name: Harzhauser, Mathias
name: Winkler, Viola
name: Metscher, Brian
name: Ruthensteiner, Bernhard
name: Jochum, Adrienne
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Ellobiida
Ellobiidae
Zospeum
Zospeum costatum

description: Zospeum costatum (Freyer, 1855)
Fig. 5
Carychium costatum Freyer, 1855, Sitzungsber. mathem. - naturw. Cl. kais. Akad. Wiss. Wien, 15 (1): 20, pl. [1] fig. 5 a – c (shell) [Von Herrn Ferd. Schmidt in der Grotte bei Goric ̌ ane unweit des fu ̈ rstbischo ̈ flichen Schlosses Go ̈ rtschach entdeckt (Babja Luknia, near Goric ̌ ane)].
Carychium bidentatum Hauffen, 1856, Verh. zool. - bot. Ges. Wien, Abh., 6: 701, pl. 7 fig. 5 (shell) [„ in der Grotte am Glaven vrh “ (Hauffen leg., 17 exx.)] (Hauffen 1856 b).
Material examined.
Carychium bidentatum Hauffen: imaged syntypes BOKU F 3444 a (Grotte hinter Laak), BOKU 3473 a (Glaven vrh); other syntypes BOKU F 3444 b, BOKU F 3444 d, Cave behind Laak, coll. Bilimek ex Hauffen 1856.
Diagnosis
(Freyer, original from German). Vertically ribbed, bidentate carychid.
Description
(Freyer, original from German). Shell white, spired, overlayed with strongly pronounced vertical ribs. Those of the first four graded whorls are weaker, those of the sixth whorl do not reach the ventral side, hence the ventral side [umbilical zone] (fig. c) is smooth before the aperture; about 1 / 3 the distance beyond the peristome, five ribs extend from the umbilicus nearly fusing together with some obliquely oncoming ribs from the upper part of the whorl as shown in Fig. 5 C. The peristome is flatly bent back, the palatal lip is dented, the left columellar side sinks straight down, flattening at the rounded basal part of the aperture. Aperture shaped like a gourd. The ridge-like denticle nearest the columella [columellaris] reaches to the leftmost side of the parietal shield; the second, shorter ridge-like denticle [parietalis] extends from the parietal side and lies directly across from the shouldered edge of the right apertural lip. Height 2 1 / 8 mm, Width 1 1 / 3 mm.
Measurements.
(BOKU F 3444 from “ Grotte hinter Laak ”, Slovenia): sh = 2.14 mm; sw = 1.09 mm; ah = 0.86 mm; aw = 0.67 mm; hlw = 1.17 mm; SA = 59.08 deg.
Distribution.
(Hauffen Z. costatum) Cave behind Laak, Slovenia.
Enhanced description of Z. costatum based on integrative taxonomic analyses of Inäbnit et al. (2019) and Micro-CT and SEM Data in this work.
Diagnosis. Shell ca. 2 mm, transparent, ribbed, with weak spiral lines, elongate-conical with an auriform and more or less thickened peristome, bearing four apertural barriers, two of which continue on the columella as lamellae.
Description. Shell conical, translucent when fresh; whorls somewhat shouldered, usually stronger than in Z. spelaeum; pronounced, equidistantly-spaced axial ribs present on each whorl, though not always covering an entire whorl; weak spiral striae are usually visible; aperture taller than wide, the upper half of the palatal rim shouldered and expanded; the parietal shield well differentiated from lip, its margin more curved than straight; parietalis well developed in the aperture, extending one whorl into the shell; columellaris visible in aperture, extending 3 ⁄ 4 of a whorl into the shell; palatalis always present; angularis sometimes present. Internally, the base of the columella continually widens from below the point of attachment of the short, oblique lamella, forming a robust base above the umbilicus (Fig. 5 E). The low columellaris increases structural form as it swells up towards the base of the columella (aperture facing right) (Fig. 5 G), reaching its fullest size at half-way its distance on the columella (dorsal perspective) (Fig. 5 F). Visible also in NHMW - MOL- 71847 from Babja luknja, Goric ̌ ane (fig. 5 c 1–3) (Inäbnit et al. 2019).
The Z. costatum shells (BOKU F 3444 a and BOKU 3473 a) show the same lamella to columellar configuration as that seen in NHMW - MOL- 71847 (Inäbnit et al. 2019) as well as the mode and degree of smoothness versus interconnected ribbing described by Freyer (1855) on the body whorl and the ventral side (Fig. 5 J – K, M).
Considering the 10 specimens investigated in Inäbnit et al. (2019) and the two individuals in this study, Z. costatum differs from Z. spelaeum by the generally more expanded shoulder of the upper palatal rim (not visible in the broken shell of BOKU 3473 a from Glaven vrh) and the swollen, wider basal configuration of the columella; differs from Z. lamellatum by its smaller, single lamella and reduced dentition; differs from Z. lautum by the marked presence of ribs and presence of a single lamella; differs from Z. trebicianum by its enhanced degree of ribbing and larger size.
description: Published as part of Lukeneder, Petra, Ottner, Franz, Harzhauser, Mathias, Winkler, Viola, Metscher, Brian, Ruthensteiner, Bernhard & Jochum, Adrienne, 2024, Lost & Found - Rediscovery of H. Hauffen's Carychium material in the Dominik Bilimek Collection, BOKU University, including a contemporary assessment within the genus Zospeum (Gastropoda, Ellobioidea, Carychiinae), pp. 97-116 in Subterranean Biology 49 on pages 97-116, DOI: 10.3897/subtbiol.49.130692