Radomaniola pesici, 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 : 423-425

RADOMANIOLA PESICI SP. NOV.

( FIGS 18 , 19 )

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. o r g: a c t: 42A9C1DA-B6A9-40BE-9A96-4F381D133CA2

Etymology: Named after Professor Vladimir PeŠić, collector of this species, in recognition of his valuable contribution to the knowledge of the fauna of Montenegro.

Type material: Holotype ( MNCN 15.05 /200163), five paratypes ( MNCN 15.05 /200164) in the MNCN collection and ~ 20 paratypes ( UGSB 19048 ) in the

UGSB collection. Type locality: Bar Spring , Donje Vrelo, Montenegro .

M a t e r i a l s t u d i e d: B a r S p r i n g, D o n j e V r e l o, Montenegro, 42.86°N, 20.25°E , V.P., May 2005 , MNCN 15.05 /200164 and UGSB 19048 (80% ethanol) .

Diagnosis: Protoconch microsculpture wrinkled; central radular tooth formula 7-C-7/1-1; bursa copulatrix globular, with a long duct; SR1 elongate, duct short; SR2 slightly shorter than SR1, elongate, duct short; penis unpigmented, gradually tapering, base narrow, approximately as long as head length; nervous system weakly pigmented, moderately concentrated (mean RPG ratio = 0.47).

Description: Shell ovate-conic, 3.5–4.0 whorls, height 1.75–2.25 mm ( Fig. 18A–D ; Supporting Information, Table S6). Periostracum whitish. Protoconch ~400 µm wide, 1.5 whorls; nucleus ~150 µm wide; protoconch microsculpture pitted ( Fig. 18G ). Teleoconch whorls convex, with deep sutures; body whorl large, occupying about three-quarters of total shell length. Aperture slightly oval; inner lip thicker than outer lip; peristome margin simple, straight ( Fig. 18B ). Umbilicus narrow, not covered by the inner lip. Operculum oval, brownish, about two whorls; muscle attachment area oval and located near the nucleus ( Fig. 18E, F ). Radular length intermediate, ~600 µm (~25% of total shell length), with ~60 rows of teeth ( Fig. 18H ). Central tooth formula 7-C-7/1-1 ( Fig. 18I ); basal tongue U-shaped, length about equal to lateral margin. Lateral tooth formula 4-C-4. Inner marginal teeth having 30–32 tapered cusps, shortening toward the base. Outer marginal teeth with 30–35 sharp cusps ( Fig. 18J ).

Animal darkly pigmented except for neck and tentacles ( Fig. 19F ). Ctenidium with ten or 11 welldeveloped gill filaments, occupying ~50% of pallial cavity length and positioned posteriorly. Osphradium of intermediate width and opposite middle of ctenidium ( Fig. 19A ). Stomach as long as wide, with two chambers almost equal in size; style sac longer than wide, surrounded by an unpigmented intestine ( Fig. 19B ; Supporting Information, Table S7). Nervous system slightly pigmented, moderately concentrated (mean RPG ratio= 0.47); cerebral ganglia approximately equal in size, presenting small black granules ( Fig. 19C ).

Female glandular oviduct approximately two times longer than wide. Albumen gland shorter than capsule gland. Bursa copulatrix globular, slightly longer than wide. Bursal duct longer than bursal length. Renal oviduct unpigmented, coiled. SR1 elongate, duct short, joining renal oviduct slightly above the insertion point with bursal duct. SR2 slightly shorter than SR1, elongate, with a short duct, located on renal oviduct near loop ( Fig. 19D, 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. 19H ). Penis unpigmented, gradually tapering, approximately as long as head length, base narrow, weakly folded along inner edge and with one medial outgrowth on its left side ( Fig. 19F, G ; Supporting Information, Table S9); penis attached well behind the right eye; penial duct narrow, near outer edge, almost straight.

Remarks: This species resembles R. montana and R. filiola in bearing a more ovate shell than other congeners. Anatomically, R. pesici differs from the two species according to its larger bursa copulatrix, more slender penis, longer radula and larger central radular teeth. Average sequence divergence among the three species ranges between 5.3 and 7.9% for COI. Radomaniola pesici is also differentiated from the geographically proximate R. curta and R. wolffi in its shorter and more ovate shell, a larger number of cusps on the central and lateral teeth, smaller bursa copulatrix with a shorter duct, shorter penis and an average sequence divergence of 4.5–6.2% for COI (Supporting Information, Table S4).

Figures

Figure 18. Shells, operculum and radulae of Radomaniola pesici sp. nov. A, B, holotype (MNCN 15.05/200163). C–J, paratypes (UGSB 19048). 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 19. Anatomy of Radomaniola pesici sp. nov. A–H, paratypes (UGSB 19048). 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.