Annulobalcis wareni, DGEBUADzE & FEDOSOv & Kantor, 2012

DGEBUADzE, Polina Y., FEDOSOv, Alexander E. & Kantor, Yuri I., 2012, Host specificity of parasitic gastropods of the genus Annulobalcis Habe, 1965 (Mollusca, Gastropoda, Eulimidae) from crinoids in Vietnam, with descriptions of four new species, Zoosystema 34 (1), pp. 139-155 : 146-148

Annulobalcis wareni n. sp.

( Figs 3 ; 6F )

TYPE MATERIAL. — Vietnam. South China Sea. Nha Trang Bay, Mun Island (Rock Rom), 12°10’12.51”N, 109°18’46.06”E, 5-7 m, holotype ( MNHN 24192).

Same data as holotype, 2 paratypes ( ZIN 61121, MNHN 24193).

OTHER MATERIAL EXAMINED. — 12 specimens from Comaster nobilis (Carpenter, 1884) (Comasteridae) , 3 specimens sequenced ( JF717841 - JF717843 ), stored in the Laboratory of Marine Invertebrates of A. N. Severtzov Institute of Ecology and Evolution.

DISTRIBUTION. — South China Sea, Nha Trang Bay, Vietnam.

ETYMOLOGY. — The present species is named in honour of Dr Anders Warén, the leading specialist in family Eulimidae as well as in other molluscs.

DESCRIPTION (HOLOTYPE)

Shell conical, glossy, greyish white, semi transparent, smooth except thin sigmoid scars corresponding to outer lip form.

Larval shell is pointed, conical, smooth, consists of> 4 slightly convex whorls, diameter 400 Μm. Boundary between protoconch and teleoconch marked by thin, but distinct sigmoid scar. Teleoconch of four whorls.

Larval shell with axis curved and expansion rate lower than other whorls of teleoconch. Suture shallow, false suture seen by transparency. Teleoconch whorls slightly convex. Last whorl comprises 0.6 of shell height.

Aperture ovate with angulated junction of columellar and parietal margins, 0.34 of shell height. Columellar margin weakly convex, more than half of aperture height. Parietal margin evenly rounded, without callus. Outer lip evenly rounded in ventral view, in lateral view forms deep anal sinus near suture, lip most protruded in its middle part.

Soft parts are visible through shell in paratypes.

Measurements

See Table 4.

Host

Molluscs were found on cirri and lower side of calyx of crinoids Comaster nobilis (Comasteridae) .

Morphology and colouration

Body colourless in live specimens ( Fig.6F ).Foot semitransparent with central longitudinal non transparent white stripe. Tentacles yellow. Eyes well developed, black, situated at tentacles base. Proboscis present, pseudopallium absent.Operculum present ( Fig.3G ), spiral, oval, nucleus close to columellar margin.

Intraspecific variability

Paratypes are very similar to holotype in shell shape and morphology. Shell tending to become more slender (decreasing of SW/SH ratio) with increasing of its height. There is also a tendency to decreasing of LWH/SH ratio with increasing of the shell height. Paratype 1 has more extended and protruded outer lip than holotype.

Due to their small size and fragile shell the sequenced specimens were destroyed. The remaining specimen collected from the same host specimen ( Fig. 3F ; Table 4, specimen 1) is very similar to the type series and no doubt of conspecifity of sequenced specimens and type material remains.

REMARKS

The new species is different from Annulobalcis shimazui in absence of spiral sculpture and thus resembles Annulobalcis marshalli , but differs from this species by shell form, size and lower AH/SH ratio. The present species differs from Annulobalcis cicatricosa by irregular growth of the shell and less convex teleoconch whorls. The new species resembles Annulobalcis albus n. sp. in shell shape. Younger specimens are characterized by much more swollen and globose last whorl than in A. albus n. sp. Nevertheless the adults are more similar in shell proportions, although A. wareni n. sp. has in general more convex last whorl, obtusely angled. Both species are distinctly different in Cox1 sequence and live on different host species.

Figures

FIG. 3. — Annulobalcis wareni n. sp.: A, B, holotype (MNHN 24192); C, D, paratype 1 (ZIN 61121); E, paratype 2 (MNHN 24193); F, specimen 1 (Table 5) collected from the same host as the sequenced ones; G-J, specimen 2 (Table 5) collected from the same host as the sequenced ones; G, operculum, SEM; H, SEM of the shell; I, J, apex in different views, SEM. Scale bars: A-F, H, 1 mm; G, 500 μm; I, 200 μm; J, 100 μm.

FIG. 6. — A, live specimen of Annulobalcis albus n. sp.; B, Annulobalcis albus n. sp. specimens on their host Oxycomanthus benetti (Müller, 1841); C, Annulobalcis vinarius n. sp. on arm of crinoid Himerometra robustipinna Carpenter, 1881; D, live specimen of Annulobalcis vinarius n. sp.; E, eggs capsules of Annulobalcis vinarius n. sp. on crinoid Himerometra robustipinna; F, live specimen of Annulobalcis wareni n. sp. Scale bars: A, C-F, 1 mm; B, 10 mm.