Radomaniola wolffi, Delicado & Hauffe, 2022

Delicado, Diana & Hauffe, Torsten, 2022, Shell features and anatomy of the springsnail genus Radomaniola (Caenogastropoda: Hydrobiidae) show a different pace and mode of evolution over five million years, Zoological Journal of the Linnean Society 196, pp. 393-441 : 430-433

RADOMANIOLA WOLFFI SP. NOV.

( FIGS 24 , 25 )

Z o o b a n k r e g i s t r a t i o n: z o o b a n k. org:act: 7373D604-929B-4E92-AF4E-11F19EB6DD96

Etymology: Named after Christian Wolff, collector of this and other gastropod species in the Balkan Peninsula.

Type material: Holotype ( MNCN 15.05 /200171), ten paratypes ( MNCN 15.05 /200172) in the MNCN collection and ~ 50 paratypes in the UGSB collection

(UGSB 19533). Type locality: Vitoja Spring , north of Lake Scutari, Montenegro .

Material studied: Vitoja Spring , north of Lake Scutari, Montenegro, 42.3252°N, 19.3628°E, T.H. and C.W., 20 September 2009, MNCN 15.05 /200172 and UGSB 19533 (80% ethanol) .

Diagnosis: Protoconch microsculpture wrinkled; central radular tooth formula (3)4-C-4(3)/1-1; bursa copulatrix ovoid, with a duct as long as bursal length; SR1 pyriform, duct long; SR2 pyriform, duct short; penis unpigmented, gradually tapering, base narrow, longer than head length; nervous system weakly pigmented, moderately concentrated (mean RPG ratio = 0.45).

Description: Shell ovate-conic, 4.0–4.5 whorls, height 2.3–3.0 mm, apex often eroded ( Fig. 24A–D ; Supporting Information, Table S6). Periostracum yellowish. Protoconch ~450 µm wide, 1.5 whorls; nucleus ~175 µm wide; protoconch microsculpture wrinkled ( Fig. 24G ). Teleoconch whorls convex, with deep sutures; body whorl large, occupying about two-thirds of total shell length. Aperture slightly oval; inner lip thicker than outer lip; peristome margin simple, straight ( Fig. 24B ). Umbilicus narrow, not covered by the inner lip. Operculum oval, brownish, about two whorls; muscle attachment area oval and located near the nucleus ( Fig. 24E, F ). Radular length intermediate, ~600µm (~25% of total shell length), with ~45 rows of teeth ( Fig. 24H ). Central tooth formula (3)4-C-4(3)/1-1 ( Fig. 24I ); basal tongue U-shaped, length about equal to lateral margin. Lateral tooth formula 3-C-3. Inner marginal teeth having 18–20 tapered cusps, shortening toward the base. Outer marginal teeth with 21–25 sharp cusps ( Fig. 24J ).

Animal darkly pigmented except for neck and tentacles ( Fig. 25F ). Ctenidium with 14–17 welldeveloped gill filaments, occupying ~50% of pallial cavity length and positioned posteriorly. Osphradium of intermediate width and opposite middle of ctenidium ( Fig. 25A ). Stomach slightly longer than wide, with two chambers almost equal in size; style sac longer than wide, surrounded by an unpigmented intestine ( Fig. 25B ; Supporting Information, Table S7). Nervous system slightly pigmented, moderately concentrated (mean RPG ratio = 0.45); cerebral ganglia approximately equal in size, presenting small black granules ( Fig. 25C ).

Female glandular oviduct approximately two times longer than wide. Albumen gland shorter than capsule gland. Bursa copulatrix ovoid, slightly longer than wide. Bursal duct as long as bursal length. Renal oviduct unpigmented, coiled. SR1 pyriform, duct long, joining renal oviduct slightly above the insertion point with bursal duct. SR2 shorter than SR1, pyriform, with a short duct, located on renal oviduct near loop ( Fig. 25D, E ; Supporting Information, Table S8).

Male genitalia with a prostate gland approximately two times longer than wide, bean shaped; seminal duct entering the middle-posterior region; pallial vas deferens emerging close to its anterior edge ( Fig. 25H ). Penis unpigmented, gradually tapering, longer than head length, base narrow, weakly folded along inner edge and with one medial outgrowth on its left side ( Fig. 25F, G ; Supporting Information, Table S9); penis attached well behind the right eye; penial duct narrow, near outer edge, almost straight.

Habitat: Known only from a cold, large, karstic spring, Vitoja Spring, in Montenegro (for details of this locality, see Grego et al., 2019). The water conductivity was low (245 µS/cm) and vegetation sparse. The species was found mainly on stones, rocks, walls and detritus. Other gastropod species co-occurring in this spring are Pyrgula annulata (Linnaeus, 1758) , Theodoxus sp. , Bithynia sp. , Planorbarius sp. , Valvata sp. and Galba truncatula (Müller, 1774) .

Remarks: This species is conchologically similar and geographically proximate to Radomaniola elongata ( Radoman, 1973) , which was originally described based on the shell ( Radoman, 1973), and only the anatomy of its penis is known (Falniowski et al., 2012). However, they can be distinguished by the narrower penis in R.wolffi ( Fig. 25G ) and an average sequence divergence of 9.1% for COI (Supporting Information, Table S4). Another Radomaniola species from the Lake Scutari region, Radomaniola lacustris ( Radoman, 1983) , for which only shell features are known ( Radoman, 1983), differs from R. wolffi in having a more globose shell with a larger aperture.

Figures

Figure 24. Shells, operculum and radulae of Radomaniola wolffi sp. nov. A, B, holotype (MNCN 15.05/200171). C–J, paratypes (UGSB 19533). C, D, shells. E, F, operculum (E, inner side; F, outer side). G, protoconch. H, portion of radula ribbon. I, central radular teeth. J, outer marginal teeth.

Figure 25. Anatomy of Radomaniola wolffi sp. nov. A–H, paratypes (UGSB 19533). A, ctenidium and osphradium. B, stomach. C, partial nervous system. D, pallial oviduct. E, bursa copulatrix and seminal receptacles. F, head of male and penis. G, penis. H, prostate gland.