Zospeum spelaeum ( Rossmaessler, 1839 )

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), Subterranean Biology 49, pp. 97-116 : 97-116

Zospeum spelaeum ( Rossmaessler, 1839)

Figs 2 , 3 , 4

Carychium spelaeum Rossmaessler, 1839 , Icon., (1) 2 (1 / 2): 36–37, pl. 49 fig. 661 (shell) [in der Adelsberger Höhle in Krain an Stalaktiten (Postojnska jama, near Postojna)].

Carychium reticulatum Hauffen, 1856 , Verh. zool. - bot. Ges. Wien, Abh., 6: 623–624, pl. 7 fig. 4 (shell) [In der Grotte Bidou sturm (Hauffen leg.; Dobruška jama, near Vodice)].

Zospeum spelaeum : twelve junior synonyms are attributed to Z. spelaeum (see Inäbnit et al. 2019).

Material examined.

Carychium reticulatum Hauffen : imaged syntype BOKU F 3434 b , other syntypes BOKU F 3434 a , BOKU F 3434 j , Cave Bidou sturm [= Dobruška jama], coll. Bilimek ex Hauffen 1856 .

Diagnosis

(Hauffen original from German). “ Distinct vertical and horizontal lines form an entirely complete network pattern unique to this species ”.

Description

(Hauffen original from German). “ Shell with 6 whorls, the last is relatively large; suture moderate; shell glassy and transparent; the sculpture is ribbed with the ribs largest by the suture, between these are often smaller ribs which extend to the middle of the whorl, the long ribs begin in most cases at the third whorl and continue over the cross ribs; near the suture they are closer to each other, in the middle of the whorl [zone of greatest convexity] they are however further apart, these crossed over ribs form a network, hence the name; umbilicus somewhat open at the beginning, however closing rapidly, aperture elongate, peristome rim bent backwards, lipped, dented in on the right side; columella somewhat swollen, on which a small denticle is in the middle, which lies deeper inside the aperture, on the inner parietal side are two denticles, the one nearest the columella is the larger and begins closest to the opening, it is next to the smaller one, which lies deeper in the aperture, bending to the right, this smaller interior denticle is visible in some shells and barely visible in others, the parietal shield shows tiny pitting. Height 2.0– 2.2 mm. Width 1.5 mm. ”

Measurements.

( BOKU F 3434 b from Bidou sturm): sh = 2.14 mm; sw = 1.26 mm; ah = 1.01 mm; aw = 0.84 mm; hlw = 1.43 mm; SA = 58.55 deg.

BOKU F 3429 from Douga jama: sh = 1.96 mm, sw = 1.18 mm; ah = 0.94 mm; aw = 0.78; hlw = 1.29; SA = 59.90 deg.

Distribution

(Hauffen Z. spelaeum ). Caves Bidou sturm (= Dobruška jama) and Douga jama.

Remarks.

Hauffen also recorded this species from a cave behind Laak. Re-investigation of his specimens from that cave herein (Fig. 5 ) revealed that they are not conspecific with Z. spelaeum from Bidou sturm (Figs 2 , 3 ) but rather, with the species Z. costatum ( Freyer, 1855) (see Inäbnit et al. 2019, fig. 5, C 1–3).

Enhanced description of Z. spelaeum based on integrative taxonomic analyses of Inäbnit et al. (2019) and Micro-CT and SEM Data in this work.

Diagnosis. Shell ca. 1.96 mm, transparent, elongate, or elongate-conical with an auriform and more or less thickened peristome, bearing two to three apertural barriers; columella with a single lamella.

Description. Shell conical, often more slender than other species, translucent when fresh; whorl never well rounded [as, for example, in Zospeum frauenfeldii ( Freyer, 1855) ], usually ovate-conic in form; shell surface usually ribbed, but variable, which has been used to differentiate subspecies in the past (present on the whole whorl as in “ Z. s. costatum ”, present on the upper part of the whorl as in (Z. s. schmidtii (fig. 4 f – n) or completely absent as in (Z. s. spelaeum ) (fig. 4 a – e) ( Inäbnit et al. 2019)), but the spectrum of variation within populations is too broad to establish congruence here; aperture taller than wide, the palatal side usually shouldered; the parietal shield well- differentiated from the lip, its shape either convex or straight; parietalis well-developed in the aperture, extending one whorl into the shell; columellaris visible in the aperture, in some cases disappearing within half a whorl into the shell or continuously weakening; a more or less oblique lamella is present above the middle of the short columella; a basal bulge is present just above the umbilicus; angularis in most cases present as a tooth of variable prominence; palatalis usually present. Protoconch covered with pits; interconnected pits on top of the protoconch densely aggregated into rows; pits on the side of the whorl distributed more randomly. Details of the radula and the Z. spelaeum clade within the most recent phylogeny of Zospeum are available in Inäbnit et al. (2019).

The Z. spelaeum shells herein ( BOKU F 3434 b and BOKU F 3429) show a well-formed oblique lamella on a centrally aligned columella, the base of the columella shows a basal, lamella-like bulge in dorsal and aperture facing right views (Figs 3 F – G , 4 H ), forming the more or less pronounced columellaris, which ends deep in the shell and is visible behind the peristome on the columellar side (Figs 3 A, E , 4 D, F ); the robust and well-developed parietalis extends one whorl into the shell, tightly exiting the columellar side of the peristome far up on the parietal shield, ending either before or up to its outermost edge (Fig. 3 A, D ); umbilical depression deep; columellar side of peristome arches over and oblique to umbilical depression on ventral side (Figs 3 D , 4 K ), alignment of last ¼ whorl not compact. Central part of protoconch partially covered with interconnecting pits and singular pits aggregated in rows (Figs 3 I , 4 L ); onset of ribbing begins at suture of second or third whorl and with increased reticulation of the third whorl some distance from the suture. More or less enhanced reticulation begins at the fourth whorl (Fig. 3 H ).

Considering the 148 specimens investigated in Inäbnit et al. (2019) and those of this study, Zospeum spelaeum differs from Z. costatum by a less expanded upper section of the palatal side of the aperture; from Z. lamellatum Bole, 1974 by its greatly reduced external ribbing and number and size of lamellae and apertural barriers; from Z. lautum ( Frauenfeld, 1854) by its usually more slender shell, the presence of ribs, and its bearing a simple inclined lamella versus the more elaborate 3 - tiered lamellar configuration in Z. lautum ; from Z. trebicianum Stossich, 1899 by its larger size.

Distribution. Z. spelaeum is known from the region of Ljubljana, Slovenia westwards to the Brenta River in Italy, the region of Trieste, Italy, the island of Cres, and eastwards where the Sava River enters the Julian Alps and from the Vrlovka cave in the northeastern part of Croatia (see also De Mattia 2003).

Figures

Figure 2. Light microscopic images of Hauffen’s specimens of Carychium reticulatum var. bidentatum Hauffen, 1856 (syn. Z. spelaeum Rossmaessler, 1839) BOKU F 3434 from the type locality cave, Bidou sturm in Slovenia A – D Shell specimen BOKU F 3434 b in apertural view (A), dorsal view (B), apical view (C), umbilical view (D) E – H shell specimen BOKU F 3434 a in apertural view (E), dorsal view (F), apical view (G), umbilical view (H) I – L Shell specimen BOKU F 3434 j in apertural view (I), dorsal view (J), apical view (K), umbilical view (L). Scale bars: 1 mm.

Figure 3. Hauffen’s specimens of Carychium reticulatum Hauffen, 1856 from the type locality, Bidou sturm in Slovenia. Inventory number BOKU F 3434 A – G 3 D visualizations of Micro-CT data of specimen BOKU F 3434 b showing the columellar apparatus; apertural view (A, E), dorsal view (B, F), apical view (C), umbilical view (D), lateral view (G) H – J scanning Electron Microscopy images of shell F 3434 j (apical view) I detail of H showing protoconch J reticulated sculpture of Zospeum reticulatum Hauffen, 1856 K broken shell of specimen BOKU F 3434 d in dorsal view exhibiting collumellar apparatus L collection label of BOKU F 3434. Scale bars: 1 mm (A, B, C, D, E, F, G); 100 µm (H, I, J); 1 cm (L).

Figure 4. Hauffen’s specimens of Carychium ” reticulatum var. bidentatum Hauffen, 1856 (syn. Z. spelaeum Rossmaessler, 1839) from Glaven verh (Slovenia) and from Douga jama cave (Slovenia) A, B light microscopic images of broken shell BOKU F 3473 a from Glaven verh showing apertural view (A), apical view (B) C collection label of broken shell BOKU F 3473 a D – K specimens of BOKU F 3429 from Douga jama (Slovenia) D, E light microscopic images of specimen BOKU F 3429 a showing apertural view (D), dorsal view (E) F – K 3 D visualizations of Micro-CT data of specimen BOKU F 3429 b; apertural view (F), apertural view showing columellar apparatus (G), dorsal view showing columellar apparatus (H), lateral view (I), apical view (J), umbilical view (K) L, M scanning Electron Microscopy images of shell of BOKU F 3473 a from Glaven verh (L apical view M detail of reticulate microstructure on teleoconch) N collection label of BOKU F 3429 with notation referring to Douga jama locality. Scale bars: 1 mm (A, B, D, E, F, G, H, I, J, K); 100 µm (L, M); 1 cm (C, N).

Figure 5. Hauffen’s specimens of Zospeum costatum (Freyer, 1855) from Laak in Slovenia. Inventory number BOKU F 3444 A – D shell specimen F 3444 b in apertural view (A), dorsal view (B), apical view (C), umbilical view (D) E – G 3 D visualizations of Micro-CT data of shell specimen BOKU F 3444 a showing the columellar apparatus. Apertural view (E), dorsal view (F), lateral view (G) H, I scanning Electron Microscopy images of shell specimen BOKU F 3444 b (apical view) J – M shell specimen F 3444 d in apertural view (J), dorsal view (K), apical view (L), umbilical view (M) N collection label of BOKU F 3444 with characteristic handwriting of Heinrich Hauffen. Scale bars: 1 mm (A, B, C, D, E, F, G, J, K, L, M); 100 µm (H, I); 1 cm (N).