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Common Name

"Andaman Sea Cone"

Status

Regarded as a valid species.

Type Locality

off Port Blair, Andaman Islands

Distribution

Andaman Sea

Maximum Reported Size

41.2 mm

Description

Moderately small, moderately light. Last whorl conical, ventricosely conical or conoid-cylindrical, outline slightly convex; left side slightly concave at base. Aperture wider at base than near shoulder. Shoulder subangulate to rounded. Spire of low to moderate height, outline concave. Larval shell of about 2.5 whorls, maximum diameter about 0.8 mm. Teleoconch sutural ramps nearly flat to slightly convex, with 2 increasing to 3 rather weak spiral grooves; late ramps either with obsolete spiral sculpture or 2-3 spiral grooves. Basal third to half of last whorl with widely spaced punctate spiral grooves and ribbons between; ribbons may grade to ribs at anterior end.

Ground colour white to bluish grey, may be suffused with pink. Last whorl with variably numerous, orangish to dark reddish brown dots, spots, spiral bars and small axial markings, irregularly scattered and sometimes additionally arranged in 2-3 spiral rows, on each side of central third and sometimes also below shoulder. Larval whorls white to beige. Late sutural ramps with orangish to dark reddish brown radial lines or streaks. Aperture white, may be orangish brown or violet-brown deep within.

Periostracum greyish brown, thin, translucent, smooth.

Shell Morphometry

L	26-31 mm
RW	0.07-0.13 g/mm
RD	0.54-0.60
PMD	0.77-0.87
RSH	0.10-0.16

Habitat & Habits

Intertidal and shallow subtidal; in sand.

Discussion

Description is based on the figure of an adult specimen given by Smith (31 x 15 mm) and closely corresponding shells from old collections in MNHN, coll. Salminger, and coll. Filmer; the 2 syntypes in BMNH are subadult. C. andamanensis has been assigned to C. collisus (Coomans et al., 1980) and to C. subulatus (Walls, [1979]; da Motta, 1986). We provisionally consider C. andamanensis a valid species (cf. Richard, 1990). C. collisus has a more angulate shoulder and its aperture is narrower; it also differs in more pronounced spiral grooves on its late sutural ramps, stronger spiral ribs and ribbons on its last whorl, and a last whorl pattern with larger and confluent markings as well as dotted or dashed spiral lines, and irregularly scattered markings are absent.

References

• Proc. Zool. Soc. Lond. Pt. 21. No. 255: p. 119. No. 18, not figured.