Entadella kilchomani Páll-Gergely, 2019

Páll-Gergely, Barna & Hunyadi, András, 2019, Two new species of Entadella Páll-Gergely & Hunyadi in Páll-Gergely et al., 2016 from Vietnam (Gastropoda: Heterobranchia: Camaenidae), Raffles Bulletin of Zoology 67, pp. 694-700 : 698-700

Entadella kilchomani Páll-Gergely , new species

( Figs. 1C–F , 4 , 5 )

Type material. Holotype (1 shell, D: 34.9 mm, H: 19.3 mm) ( NHMUK 20190591 ), Vietnam, Huu Lien Natural RF, Site 32, coll. no. 408 V, 21°39.569′N, 106°21.921′E, coll. NHM 2013 Vietnam Expedition, 18 September 2013; 1 ethanolpreserved paratype (broken shell, body, prepared genitalia) ( NHMUK 20140589 ), same data as holotype.

Description. Shell large, dextral, thick-walled, light chocolate brown in colour ( Fig. 1C ). Shell rather flat with slightly elevated spire. Dorsal surface domed. Shell outline rounded from dorsal view, whorls grow regularly. Body whorl rounded, somewhat shouldered due to slight depression from ventrolateral direction. Whorls 6.75–7, convex, separated by moderately deep suture. Protoconch consisting of almost 2 whorls, smooth, with some slight indication of irregular growth lines ( Fig. 1D ). Teleoconch sculpture dominated by low, irregular growth wrinkles and slight spiral striation that appears on the dorsal side after 3.5 whorls ( Fig. 1E, F ), and remains equally strong until peristome. Spiral striae much denser on ventral than on dorsal side, radial growth wrinkles lower on ventral than on dorsal side. Umbilicus open but very narrow, point-like, shows all whorls. Its edge covered by reflected peristome. Aperture semilunar, slightly elongated in direction of umbilicus, slightly oblique to the shell axis from lateral view. Peristome similar to shell in colour, strongly thickened and reflected, with a slight thickening on basal part of the holotype (not visible on paratype, which is seemingly a less matured shell). Parietal callus present only as transparent, fine calcium layer on the parietal shell wall, its surface is finely granulate, less glossy than rest of shell.

Measurements. D = 34.9 mm, H = 19.3 mm (holotype).

Description of the anatomy. Figs. 4 , 5 . Right ommatophoral retractor crosses penis and vagina. Atrium very short. Penis with a short, slender distal, and a slightly longer, much thicker proximal part. Inner penial wall with irregular, low, longitudinal folds having perpendicular projections resulting in a reticulated surface. Penial verge large, thickened, clubshaped, with a slit-like opening on the lateral side. Epiphallus thick, but thinner than proximal part of penis, slightly shorter than penis, internally with 3–4 elevated, longitudinal folds that are discernible inside penial verge as well. Retractor muscle inserts on distal part of epiphallus. Vas deferens normally developed. A thin membrane was found between vas deferens and penis-epiphallus, and vas deferens and distal end of flagellum. Flagellum strongly developed, approximately as long as penis and epiphallus combined, its end divided into a pointed and a blunter tip. Longitudinal folds of epiphallus continue into pointed end of flagellum, whereas the blunt flagellum tip seemingly forms an independent cavity with thick, transversely sculptured wall, and two small flagellar papillae. Vagina short, shorter than penis, internally with ca. 12 longitudinal, wavy folds, which continue inside stalk of bursa copulatrix for some distance (possibly the vagina and the distal end of bursa’s stalk form a single functional unit). The wavy folds abruptly transform into straight folds inside lumen of bursa’s stalk. Stalk of bursa very long, bursa oval, large. Spermoviduct normally developed. Albumen gland and talon were not examined.

Differential diagnosis. Entadella kilchomani Páll-Gergely , new species, differs from Entadella entadiformis by the more strongly built, less depressed shell having regularly shaped whorls, the lack of tubercles on the protoconch, the less elongated aperture, and the much stronger peristome. Entadella athrix is smaller (D: 24.6–26.7 mm, H: 13.8–15.1 mm, n = 4 [MNHN 2012-27112, MNHN 2012-27125]), has a wider umbilicus, and a much thinner peristome. Entadella concava , new species, is smaller than Entadella kilchomani Páll-Gergely , new species, more depressed, and has a slightly wider umbilicus and sunken initial whorls.

Etymology. Entadella kilchomani Páll-Gergely , new species, is named after Kilchoman Distillery, the favourite whisky distillery of the first author.

Figures

Fig. 1. Shells of Entadella Páll-Gergely & Hunyadi in Páll-Gergely et al., 2016, species. A, B, lectotype of Entadella athrix (Möllendorff, 1901) (SMF 8528); B, sculpture of the ventral side, not to scale; C–F, holotype of Entadella kilchomani Páll-Gergely, new species (NHMUK 20190591); D, protoconch; E, dorsal surface; F, ventral surface. Scale “a” represents 3 mm and refers to figs. D, E, and F; scale “b” represents 30 mm and refers to figs. A and C. Note that the close-up pictures were taken using different illumination; original colours are closer to the ones on the entire shell.

Fig. 4. Genitalia of Entadella kilchomani Páll-Gergely, new species. Abbreviations: bc, bursa copulatrix; e, epiphallus; f1, pointed part of penial caecum; f2, blunt part of penial caecum; go, genital opening; p, penis; rm, retractor muscle; so, spermoviduct; v, vagina; vd, vas deferens. Scale bar represents 5 mm.

Fig. 5. Inner structure of genital organs of Entadella kilchomani Páll-Gergely, new species. A, penis, epiphallus and penial caecum (showed after opening the penial verge); B, intact penial verge; C, vagina. Abbreviations: bs, stalk of bursa copulatrix; e, epiphallus; f, flagellum; fp, flagellar papilla; f1, pointed part of flagellum; f2, blunt part of flagellum; p, penis; pv, penial verge; rm, retractor muscle; vd, vas deferens.