Range: E. Africa to Marshall Is. and Tuamotu Archipelago.

Description: Medium-sized to large, moderately solid to moderately heavy; maximum size smaller in eastern populations. Last whorl usually ventricosely conical in eastern populations, conical to sometimes broadly conical in the W. Indian Ocean; outline convex, sometimes straight centrally. Siphonal fasciole distinct, occasionally separated from basal zone by an incision. Shoulder subangulate to rounded, weakly to strongly tuberculate. Spire of low to moderate height, outline straight to moderately convex. Postnuclear spire whorls tuberculate. Teleoconch sutural ramps concave, with 1 increasing to 4-6 spiral grooves. Last whorl with weak spiral ribs at base; in subadults and small adults, ribs may be granulose and extend to shoulder.

Ground colour white. Last whorl with spiral rows of brown or black dots, clustered in 2-3 interrupted spiral bands or in axial zigzag flames; dotted areas often with underlying grey shadows, most conspicuous within spiral bands. Opaque white dashes often irregularly alternating with dark dots. Larval whorls white. Teleoconch sutural ramps variably maculated with axial clusters of brown and black dots. Aperture white, brown or pinkish orange deeper within.

Periostracum thin, velvety smooth and either translucent olive or reddish brown and opaque; large and some subadult shells usually with a thicker, opaque operculum.

Dorsum of foot cream, mottled with yellowish brown, with a dark brown to black central spot at anterior end occasionally followed by a few grey to black dots; sometimes a dotted black pre- marginal line on posterior part. Anterior edge of foot may be orangish brown. Sole of foot white to brown, sometimes darker anteriorly, mottled with tan and sometimes longitudinally streaked with brown; mottling often more pronounced laterally. Rostrum yellow. Tentacles white to pale yellow. Siphon white or pinkish white, tip orange or mottled with red; central part with a single black dorsal blotch or a narrow black to grey ring; proximal part often mottled with tan (Pl.74, Fig. 23) (Chaberman, pers. comm., 1981; Kohn, unpubl. observ.; Pearson, unpubl. observ.).

Radular teeth with an adapical barb opposite a large second barb; serration ends in a cusp; base with spur (Peile, 1939).

Habitat and Habits: Intertidal to about 30 m, living almost exclusively in sand. Mainly on wide stretches of sand on intertidal to shallow-subtidal reef flats; occasionally also in rubble mixed with sand, in mud among mangroves or on heterogeneous reef substrate (Kohn, 1961a/1968; Kohn & Nybakken, 1975; Reichelt & Kohn, 1985; Cernohorsky, 1964/1978; Sharabati, 1984). C. arenatus feeds on polychaetes of the families Capitellidae, Maldanidae, Nereidae and Eunicidae. Melo amphora Lightfoot is known to prey on C. arenatus (Kohn, 1968; Kohn & Nybakken, 1975; Reichelt & Kohn, 1985; Loch, pers. comm., 1987).

Discussion: C. arenatus resembles C. pulicarius in shell characters and often also in body colouration; for comparison, see the DISCUSSION of the latter species. Coomans et al. (1979, 1981, 1982) recognize 3 geographical subspecies: C. a. arenatus (Indonesia and Pacific); C. a. aequipunctatus (Pl. 11, Fig. 3) (Red Sea; Gulf of Aden) and C. a. bizona (Pl. 11, Fig. 2) (Kenya to Thailand). However, the pattern differences between the two western subspecies are not constant. Although C. a. bizona was described as having two bands and C. a. aequipunctatus as having three, the third band is incomplete or lacking in some specimens from the Red Sea and Gulf of Aden, and it is present in some specimens from Sri Lanka. As noted above, W. Indian Ocean shells differ in size and shape from those farther east. In form mesikatharos the central part of the last whorl is unspotted, form granulosa bears granules on the entire last whorl, and form undata shows dots arranged in flame- like axial clusters.

C. arenatus Range Map

This section contains verbatim reproductions of the accounts of 316 species of Conus from the Indo-Pacific region, from Manual of the Living Conidae, by Röckel, Korn and Kohn (1995). They are reproduced with the kind permission of the present publisher, Conchbooks.

All plates and figures referred to in the text are also in Röckel, Korn & Kohn, 1995. Manual of the Living Conidae Vol. 1: Indo-Pacific Region.

The range maps have been modified so that each species account has it own map, rather than one map that showed the ranges of several species in the original work. This was necessary because each species account is on a separate page on the website and not confined to the order of accounts in the book.