Radomaniola cetinensis Grego et Beran, 2025

Jaszczyńska, Aleksandra, Grego, Jozef, Beran, Luboš, Hofman, Sebastian, Falniowski, Andrzej & Osikowski, Artur, 2025, Five new species of Radomaniola Szarowska, 2006 (Truncatelloidea: Hydrobiidae), Zootaxa 5716 (2), pp. 207-233 : 212-217

Radomaniola cetinensis Grego et Beran sp. nov.

Zoobank number: urn:lsid:zoobank.org:act:

GenBank sequence numbers: PX113150–PX113167

mOTU D

Type locality CROATIA • Šibenicko -Kninska županja, Cviljane, Kotluša spring (locality 4: Fig. 1 ); 43°56’57”N; 16°23’56”E. 397 a.s.l.; the westernmost major source of the river Cetina , on stones in the spring zone .

Holotype CROATIA • ethanol-fixed specimen, Šibenicko-Kninska županja, Cviljane, Kotluša spring (locality 4: Fig. 1 ); 43°56’57”N; 16°23’56”E. 397 a.s.l.; 17.03.2017; Jozef Grego leg. NHMW-MO-113902. ( Fig. 4A ).

Paratypes CROATIA • 58 dry and 38 ethanol-fixed specimens, same data for holotype, 11 ethanol-fixed specimens; 8 dry and 7 ethanol fixed specimens, GMV 112630, 50 dry and 20 ethanol-fixed specimens, JG F2583 .

Description Shell ( Figs 4A–D , 5A–C and 6A–F) up to 1.70 ( type locality) or 2.26 (locality 8) mm high, ovate-conical, broad or moderately broad, with spire relatively or moderately low, with 4–5 whorls, spire height 24–26% ( type locality) or 29–30% (locality 8) of the shell height. Teleoconch whorls slightly convex, evenly rounded, growing regularly in diameter, but penultimate whorl disproportionally high in some populations (like at locality 8). Aperture moderately narrow and ovoid, outer lip simple, parietal lip complete, either narrow or broad, umbilicus slit-like. Teleoconch moderately thick-walled, its wall translucent, with delicate growth lines, periostracum yellowish. Shell measurements: Table 3, Fig. 15 . Protoconch ( Figs 4E and 5D ) growing abruptly, no sharp border between proto- and teleoconch, its micro sculpture with regular net of depressions. Operculum yellowish, smooth on both surfaces.

Radula ( Fig. 7A–B ) with central tooth with blunt ( Fig. 7A ) or sharp ( Fig. 7B ) and massive median cusp and short (less than half of the median cusp length) moderately sharp cusps following formula:

7 – 1 – 7 or (8)7 – 1 – 7(8) or 8 – 1 – 8 1 – 1 1 – 1 1 – 1

Lateral tooth with 4 – 1 – 4 moderately sharp cusps, the largest one broad and rounded. Inner marginal tooth with 25–27 long and sharp cusps, outer marginal tooth with up to 27 relatively long and sharp cusps on the terminal edge.

Soft parts morphology and anatomy Head and mantle pigmented intensely black. Female reproductive organs ( Fig. 5I ) with big spherical bursa copulatrix, broad and prominent loop of oviduct, proximal seminal receptacle (rs 2 of Radoman 1983) relatively small, distal one (rs 1 of Radoman 1983) big, elongate oval. Penis ( Figs 4F–G and 5E–H ) long and narrow, proximally broader, with low triangular outgrowth on its left side, vas deferens visible inside the penis.

Differential diagnosis From probably the most closely related species (not well supported relationship) R. frauenfeldiana sp. nov., it differs in having a bigger distal receptaculum and single outgrowth on the penis. The Molecular Diagnostic Characters in comparison with other new Radomaniola species: binary: 60(C), 69(C), 159(A), 166(C), 204 (A), 219(C), 252(A), 277(C), 297(C), 409(C), 423(C), asymmetric: 57(A). In comparison with R. frauenfeldiana : binary: 57(A), 69(C), 156(A), 166(C), 219(C), 249(G), 252(A), 303(T), 366(A), 409(C), 423(C), 429(C) (Supplementary File 2).

Etymology Named after Cetina river. The source of the Cetina River is the type locality.

Distribution and habitat Found at ten localities: 3–12 ( Figs 1 and 2A–B , Table 1): eight in central Croatia in the upper Cetina Basin and two in NW Bosnia and Herzegovina, south Livansko Polje. These are either large or small springs, rivers (Cetina), as well as interstitial habitats. At localities 3 and 10 it occurs in sympatry with R. szarowskae Delicado et Hauffe, 2022 , at locality 5 in sympatry with R. curta curta (Küster, 1895) , and at locality 11 in sympatry with R. torifera ( Schütt, 1961) .

FIGURE 6. Shell of Radomaniola : A–F— R. cetinensis sp. nov., from locality: A—3 (2K80), B—5 (1M3), C—6 (1M6), D—7 (1M4), E—10 (2K60), F—11 (2K70); G–I— R. testavariabilis sp. nov., from locality: G—15 (2L40), H—19 (2K73), I—20 (2K43); colours of mOTUs as in Figs 1 and 3 ; bar equals 1 mm. Sequences are specified by extraction numbers.

Ecological status The number of known locations is more than eight and they are distributed over 50 km long and 2–8 km broad EOO at the Upper Cetina Basin in Croatia; 22 km long and 12 km broad EOO at the lower part of Livansko Polje in Bosnia and Herzegovina and one isolated locality south of Split. The AOO is represented by scattered small local areas around several springs and adjacent small rivulets, which in total represent a much smaller total area of 15 km 2 compared with EOO. All localities are dependent upon the supply of spring water and are threatened by climatic changes resulting in droughts and disappearing or declining of the spring water outlet. Additionally, the localities are endangered by anthropogenic pollution by municipal or chemical waste, as well as by anthropogenic alterations of the springs by construction of small power stations, fountains, picnic zones, concrete-bordered channels and tap water catchments with small or no outlets of the remaining water. Therefore, it is assessed as Vulnerable (VD2).

Figures

FIGURE 1. Studied localities. Colours indicate mOTUs as in Fig. 3. Two-color dots indicate localities where individuals belonging to two mOTUs were found.

FIGURE 2. Some of the studied localities.A—spring of the river Cetina (Milaševo jezero), Croatia, locality 3; B—river Cetina near Obrovac Sinjski, Croatia, locality 10; C—spring at Bouboukas, near road to Maneli, Peloponnisos, Greece, locality 24, type locality of Radomaniola gracilipenia sp. nov.; D - spring Borak, Vrelo Lištice in Široki Brijeg, Bosnia and Herzegovina, locality 16, (photo Mario Olšavský); E and H—spring Mislina on bank of Jezero Kutac, Croatia, locality 14, type locality of Radomaniola mislinensis sp. nov. (photo Roman Ozimec); F—spring Vrioštica in Vitina, Bosnia and Herzegovina, locality 17, type locality of Radomaniola testavariabilis sp. nov. (photo Mario Olšavský); G—Vrelo Kosinac 1 in Obrovac Sinjski, Croatia, locality 15.

FIGURE 3. Maximum likelihood phylogram based on cytochrome c oxidase subunit I (COI) of the studied taxa. Bootstrap supports (if>60%) and BP given. Sequences are specified by extraction numbers. Colours indicate mOTUs as in Fig. 1. The GenBank numbers of reference sequences are also shown, after: Falniowski et al. 2012, Delicado & Hauffe 2022. New sequences obtained in this work are marked in bold.

FIGURE 4. Radomaniola cetinensis sp. nov., type locality (locality 4): A–D—shell: A—holotype, B—dissected, C—2M96, D—2M97, bar equals 1 mm; E—protoconch, bar equals 100 µm; F–G—penes, bar equals 200 µm.

FIGURE 5. Radomaniola cetinensis sp. nov., locality 12: A–C—shells: A—2L27, B—2L26, C—2L24, bar equals 1 mm; D—protoconch, bar equals 100 µm; E–H—penes, bar equals 200 µm; I—female reproductive organs (bc—bursa copulatrix, cbc—duct of bursa copulatrix, ga—albumen gland, gn—nidamental (capsule) gland, gp—gonoporus, ov—oviduct, ovl—loop of (renal) oviduct, rs1, rs2—seminal receptacle, terminology after Radoman (1973): rs1—distal, rs2—proximal).

FIGURE 7. Radulae of Radomaniola cetinensis sp. nov.: A—type locality (locality 4), B—locality 12; bar equals 50 µm.

FIGURE 15. Principal component analysis of the seven morphometric shell variables. PC1 explains 54%, PC2 36% and PC3 6% (cumulatively 96%) of the total variance.