Radomaniola testavariabilis Grego, Beran et Falniowski, 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 : 217-219

Radomaniola testavariabilis Grego, Beran et Falniowski sp. nov.

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

GenBank sequence numbers: PX113128–PX113141

mOTU A

Type locality BOSNIA and HERZEGOVINA • Bosnian Federation, Western Herzegovina Canton, Ljubuški district, Vitina, Vrelo Vrioštica spring, (locality 17: Figs 1 and 2F ); 43°14’15”N; 17°29’09”E; 93 m a.s.l.; on stones in spring and riverbed.

Holotype BOSNIA and HERZEGOVINA • Ethanol-fixed specimen ( Fig. 8A ); Vrelo Vrioštica spring, Vitina , Ljubuški district , West Herzegovina Canton, Bosnia and Herzegovina, (locality 17: Figs 1 and 2F ); 43°14’15”N; 17°29’09”E; 93 m a.s.l.; 02.04.2018; leg. Jozef Grego, NHMW-MO-113904.

Paratypes BOSNIA and HERZEGOVINA •148 ethanol-fixed and 62 dry and specimens from type locality, collected with the holotype: 15 ethanol-fixed specimens, ZMUJ/2024 /02; 10 ethanol-fixed specimens NHMW- MO-113905; 123 ethanol fixed and 62 dry specimens, JG F1219 . BOSNIA and HERZEGOVINA • 44 ethanol-fixed and 26 dry, from type locality, 22.04.2019, Jozef Grego leg., coll. JG F2583 ; BOSNIA and HERZEGOVINA • 32 ethanol-fixed specimens, from type locality, 03.09.2022, Jozef Grego and Andrzej Falniowski legs., coll. JG F3735 .

Description Shell (Figs 6G–I, 8A–E, 9A–B and 10A–B) up to 2.44 mm high, broadly ovate-conical, nearly trochiform ( type locality 11: Fig. 8A–E and locality 10: Fig. 9A–B ), with spire low, with about three whorls, spire height 11–17% of the shell height. Teleoconch whorls flat, growing rapidly in diameter, penultimate proportionally low. At localities 9, 12, 13 and 14 (Figs 6G–I and 10A–B), sharing haplotypes with the other localities, the shell turriform, with about five whorls, spire height 33% of the shell height, sutures deeper and whorls more convex and growing slower than those at the other localities. Aperture broad, ovoid, outer lip simple, parietal lip complete and broad (except at localities 9, 12, 13 and 14), umbilicus absent or slit-like. Teleoconch moderately thick-walled, its wall slightly translucent, with delicate growth lines, periostracum whitish or yellowish. Shell measurements: Table 3, Fig. 15 . Operculum yellowish or brownish, smooth on both surfaces.

Soft parts morphology and anatomy Head, mantle and visceral sac pigmented black in part. Female reproductive organs ( Fig. 8G ) with large, ellipsoid bursa copulatrix, moderately broad loop of oviduct, proximal seminal receptacle (rs 2 of Radoman 1983) relatively small, distal one (rs 1 of Radoman 1983) moderately large, elongated. Penis ( Figs 8F , 9C and 10C–D ) long, narrow and bent, proximally broad and triangular in shape, with small double outgrowth on its left side, vas deferens visible inside the penis.

Differential diagnosis From the most closely related species R. torifera it differs in having somewhat larger double outgrowth on the penis, and from R. mislinensis sp. nov. it differs in having a double instead of single outgrowth. R. testavariabilis sp. nov. differs from R. torifera especially in its female reproductive organs, with ellipsoid, not spherical bursa copulatrix, thicker loop of oviduct, proximal seminal receptacle (rs 2) smaller and distal receptaculum (rs 1) being shorter and broader. The Molecular Diagnostic Characters in comparison with other new Radomaniola species: binary: 183(A), 357(A), 429(A). In comparison with R. mislinensis and R. torifera : binary: 183(A), 357(A), 429(A).

Etymology The name reflects variability of the shell, especially of the spire height.

Distribution and habitat Found at six localities: 15–20 ( Figs 1 and 2D, F, G , Table 1): three in Croatia and three in Bosnia and Herzegovina, five of them in the southern parts of both countries. In springs, rivers (Neretva) and interstitial waters. At locality 14 in sympatry with R. torifera .

Ecological status The number of known locations is more than five, and they are distributed over 75 km long and 5–20 km broad EOO along the Tihaljina River Basin, Middle Neretva Valley and northern Popovo Polje in Bosnia and Herzegovina, with one elusive locality in Obrovac Sinjski in Croatia. The AOO is represented by scattered local small areas around several springs and adjacent small rivulets, which in total represent a much smaller total area compared to EOO. Each of the localities is dependent upon a supply of spring water and is threatened by climatic changes through droughts and disappearing or declining of the spring water outlet over longer periods. 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 objects as small power stations, houses, 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 (V).

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 8. Radomaniola testavariabilis sp. nov., type locality (locality 17): A–E—shells: A—holotype, B—2M37, C— 2M38, D—2M39, E—2M40, bar equals 1 mm; F—penis, bar equals 200 µm; G—female reproductive organs (bc—bursa copulatrix, cbc—duct of bursa copulatrix, ov—oviduct, ovl—loop of (renal) oviduct, rs 1, rs 2—seminal receptacle, terminology after Radoman (1973): rs 1—distal, rs 2—proximal).

FIGURE 9. Radomaniola testavariabilis sp. nov., locality 16:A–B—shells:A—2M76, B—2M77, bar equals 1 mm; C—penis, bar equals 200 µm.

FIGURE 10. Radomaniola testavariabilis sp. nov., locality 18: A–B—shells: A—sectioned, B—2L28, bar equals 1 mm; C–D—penes, bar equals 200 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.