Kerkia briani Rysiewska & Osikowski, 2020

Hofman, Sebastian, Rysiewska, Aleksandra, Osikowski, Artur & Falniowski, Andrzej, 2020, A new species of Kerkia Radoman, 1978 (Caenogastropoda, Hydrobiidae) from Bosnia and Herzegovina, ZooKeys 973, pp. 17-33 : 17

Kerkia briani Rysiewska & Osikowski sp. nov. Figures 4 , 5 , 6A, B , 7

Holotype.

Ethanol-fixed specimen (Fig. 4 ), spring Polički Studenac Vrelo (Crkvina), adjacent to the Trebišnjica River (42°42'46.4"N, 18°21'54.5"E), close to Trebinje (Bosnia and Herzegovina interstitially in the gravel 50 cm below the bottom of the spring. It is deposited in the Museum of Natural History of the University of Wroclaw, Poland, signature: MNHW-1350.

Paratypes.

Twelve paratypes, ethanol-fixed, in the collection of the Department of Malacology of Jagiellonian University.

Diagnosis.

Shell minute, nearly planispiral, distinguished from K. kusceri by its lower aperture of the shell and smaller non-glandular outgrowth on the left side of the penis, and from K. jadertina and K. kareli by its higher aperture of the shell and bigger the non-glandular outgrowth on the left side of the penis.

Description.

Shell (Fig. 4 ) up to 0.77 mm high and 1.39 mm broad, nearly planispiral, whitish, translucent, thin-walled, consisted of approximately five whorls, growing rapidly and separated by moderately deep suture. Spire low and flat, body whorl large. Aperture prosocline, nearly circular in shape, peristome complete and thin, somewhat swollen, in contact with the wall of the body whorl; umbilicus wide, with the earlier whorls visible inside. Shell surface smooth, growth lines hardly visible.

Measurements of holotype, sequenced, and illustrated shells: see Table 2 . Shell variability slight (Fig. 5 ).

Soft parts morphology and anatomy. Body white, without pigment, with no eyes. The ctenidium with twelve short lamellae, osphradium short and broad. Rectum forming characteristic broad loop (Fig. 6A ). The female reproductive organs (Fig. 6A, B ) with a long, moderately broad loop of renal oviduct and relatively big spherical bursa copulatrix (Fig. 6A ) with a long bent duct (Fig. 6B ), and one distal receptaculum seminis, long and worm-shaped. The penis (Fig. 7 ) elongated triangular, with a rather sharp tip and small non-glandular outgrowth on its left side, the vas deferens inside running in zigzags.

Derivatio nominis.

The specific epithet briani refers to our friend Brian Lewarne, Honorary Science Officer of The Devon Karst Research Society, and the Director for " Proteus Project in the Trebišnjica River Basin", deeply devoted to the protection of Proteus as well as the study and protection of the subterranean habitats in Bosnia and Herzegovina.

Distribution and habitat.

Known from the type locality only.

Figures

Figure 3. Measurements of the shell.

Figure 4. Holotype of Kerkia briani. Scale bar: 0.5 mm.

Figure 5. Shell variability of Kerkia briani, labels the same as in the molecular trees. Scale bar: 0.5 mm.

Figure 6. Renal and pallial section of the female reproductive organs of Kerkia briani: A the loop of oviduct in its normal position and the loop of the rectum B the loop of oviduct moved to show the receptaculum seminis and duct of bursa. Abbreviations: bc - bursa copulatrix, cbc - duct of bursa, ga - albuminoid gland, gn - nidamental gland, gp - gonoporus, ov - oviduct, ovl - loop of renal oviduct, rec - rectum, rs - receptaculum seminis. Scale bars: 1 mm.

Figure 7. Penis of Kerkia briani. Abbreviation: vd - vas deferens. Scale bar: 1 mm.