Annulobalcis maculatus, 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 : 150-152

Annulobalcis maculatus n. sp.

( Fig. 5 )

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 24196 ) .

Same data as holotype, 3 paratypes sequenced ( ZIN 61124, JF717847 ; ZIN 61125, JF717848 ; MNHN 24197 , JF717849 ) .

OTHER MATERIAL EXAMINED. — 27 specimens from crinoids Comatella nigra (Comasteridae) , stored in the Laboratory of Marine Invertebrates of A. N. Severtzov Institute of Ecology and Evolution.

DISTRIBUTION. — South China Sea, Nha Trang Bay.

ETYMOLOGY. — From the Latin “maculatus”, spotty, shows the colouration of soft parts in live specimens, red with big light spots.

DESCRIPTION (HOLOTYPE)

Shell thin, transparent, narrow, glossy, elongatedconical, with well-developed irregularly situated growth lines and scars. Shell of> 9 whorls.

Larval shell smooth consists of about> 4 whorls. Boundary between protoconch and teleoconch marked by thin sigmoid scar. Protoconch slightly curved, its whorls less convex and have lower expansion rate than whorls of teleoconch.

Teleoconch of five whorls. Suture shallow, false suture seen by transparency, narrow. Body whorl high, 0.56 of shell height. Aperture ovate with angulated junction of columellar and parietal margins, 0.36 of shell height. Parietal margin rounded, slightly convex, without callus. Columellar margin short, bulging, more than half of aperture height, slightly deflected out. Outer lip strongly convex in ventral view in middle part, nearly flat in upper part; basal part with rounded angle; in lateral view, sigmoid shape, with marked anal sinus near the suture.

Soft parts clearly visible through shell.

Measurements

See Table 6.

Host

Molluscs were found on lower side of calyx and on cirri of crinoids Comatella nigra .

Morphology and colouration

In live specimens body dark red with large yellowish spots irregularly situated on the visceral mass

whorls. Eyes well developed, black, situated at base of tentacles. Proboscis present. Operculum present, similar in morphology to other species.

Intraspecific variability

Paratypes are very similar to holotype in shell shape and morphology.

The shell growth parameters change with size: there is a weak tendency of decreasing of SW/SH ratio with increasing of shell height. There is also a tendency of decreasing of LWH/SH ratio with increasing of the shell height.

REMARKS

The present species resembles Annulobalcis vinarius n. sp. in shell form, absence of spiral sculpture, host preference and distribution. However it differs by a lower number of whorls, more convex whorls, colouration, form and type of spots distribution on soft parts. Besides both species are clearly separated by mithocondrial Cox1 sequence.

Figures

FIG. 5. — Annulobalcis maculatus n. sp.: A, B, holotype (MNHN 24196); C, D, paratype 1 (ZIN 61124); E, paratype 2 (ZIN 61125); F, paratype 3 (MNHN 24197); G-I, specimen from the same host as the types; G, H, shell SEM; I, apex, SEM. Scale bars: A-H, 1 mm; I, 200 μm.