Radomaniola frauenfeldiana Beran et Jaszczyńska, 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 : 224-225

Radomaniola frauenfeldiana Beran et Jaszczyńska sp. nov.

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

GenBank sequence numbers: MZ539646, MZ539647 , PX113147–PX113148

mOTU C

Type locality CROATIA • Splitsko-Dalamatinska županja, Kostanje-Kučiće, spring Vrutak, a small spring with cisterna at left side of road to Kostanje (locality 1); 43°26′28″N, 16°49′21″E.

Holotype CROATIA • ethanol-fixed specimen ( Fig. 13A ), Splitsko-Dalamatinska županja, Kostanje-Kučiće, Croatia, 43°26′28″N, 16°49′21″E, 31.08.2018, leg. Luboš Beran, ZMUJ2024 /04.

Paratypes CROATIA • 14 ethanol-fixed specimens from type locality, same data as for holotype, two ethanol-fixed specimens ZMUJ2024 /05, 12 ethanol-fixed specimens in coll. LB ; CROATIA • 16 dry and 36 ethanol-fixed specimens, from type locality, 26.07.2024, Jozef Grego and Roman Ozimec legs., 5 dry specimens in GMV 112631, 11 dry and 36 ethanol-fixed specimens in JG F3755 .

Description Shell ( Fig. 13A–D ) up to 2.23 mm high, ovate-conical, broad, with spire moderately low, with about 5½ whorls, spire height 28% 26–29 of the shell height. Teleoconch whorls slightly convex, evenly rounded, growing regularly and slowly in diameter. Aperture broad and nearly circular or less broad and ovoid, outer lip simple, parietal lip complete, broad in completely grown specimens ( Fig. 13A and D ), umbilicus in the form of broad and long slit ( Fig. 13A ) or incomplete slit, with parietal lip adjacent to body whorl ( Fig. 13D ). Teleoconch moderately thick-walled, its wall translucent, growth lines delicate but well visible, periostracum yellowish. Shell measurements: Table 3, Fig. 15 . Operculum yellowish, smooth on both surfaces.

Soft parts morphology and anatomy Head and mantle intensely pigmented black. Female reproductive organs ( Fig. 13E ) with big, bulky, spherical bursa copulatrix with moderately long duct, massive and thick loop of oviduct, proximal seminal receptacle (rs 2 of Radoman 1983) small, distal one (rs 1 of Radoman 1983) bigger, finger-shaped. Penis ( Fig. 13F ) slender, elongate-triangular in shape, sharply terminated, more or less broadened at its base. At the middle part of the penis, of its left side, one extremely minute and another more prominent triangular outgrowth. Vas deferens running in zigzag visible inside the penis.

Differential diagnosis From the most closely related species R. cetinensis it differs in smaller distal seminal receptacle and presence of the second, vestigial outgrowth on the penis. The Molecular Diagnostic Characters in comparison with R. cetinensis : binary: 57(A), 69(C), 166(C), 219(C), 249(G), 252(A), 366(A), 409(C), 423(C), 429(C).

Etymology Named in honour of Georg von Frauenfeld, famous Austrian malacologist, devoted also to the study of the Balkan Truncatelloidea (see Eschner 2008).

Distribution and habitat The species is known from four springs at lower Cetina Canyon.

Ecological status The AOO and EOO are represented by four springs in lower Cetina Canyon, some of them already altered by tap water reservoirs. Further construction activities of tap water supply and road construction are the main treats for the populations, together with increasing rafting tourism in the region and related infrastructure construction. The anthropogenic pollution of the springs is also related to the tourist and camping activities. Therefore, it is assessed as Vulnerable (V).

Figures

FIGURE 13. Radomaniola frauenfeldiana sp. nov., type locality (locality 1): A–D—shells: A—holotype, B–D—dissected specimens, bar equals 1 mm; E—female reproductive organs (bc—bursa copulatrix, cbc—duct of bursa copulatrix, ov—oviduct, ovl—loop of (renal) oviduct, rs1, rs2—seminal receptacle, terminology after Radoman (1973): rs1—distal, rs2—proximal); F—penis, 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.