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The Conus Biodiversity Website

CATALOGUE OF RECENT AND FOSSIL CONUS

  Conus eburneus Hwass in Bruguière, 1792.

Range: E. Africa except for Red Sea to Ryukyu Is., Polynesia, and to Australia; absent from Hawaii.

Description: Medium-sized to moderately large, moderately solid to heavy. Last whorl conical to broadly or ventricosely conical, occasionally conoid-cylindrical; outline convex to bulbous at subshoulder area and straight below; base truncate. Shoulder angulate to rounded. Spire low, outline concave to straight or sigmoid. Larval shell multispiral, maximum diameter about 0.7 mm. Teleoconch sutural ramps almost flat, with 2 narrow but deeply incised spiral grooves in early whorls and 2-5 grooves in later whorls; intervening ribs and subsutural ridge often pronounced, occasionally weak on last ramps. Last whorl with distinct to weak spiral ribs and ribbons on basal fourth to half.

Shell Morphometry
  L 35-79 mm
     (form crassus 35-63 mm)
  RW 0.23-1.20 g/mm
     (form crassus 0.23-0.73 g/mm)
  RD 0.59-0.73
     (form crassus 0.63-0.72)
  PMD 0.74-0.92
     (form crassus 0.81-0.89)
  RSH 0.02-0.10
     (form crassus 0.02-0.10)

Ground colour white. Last whorl with spiral rows of variably spaced, reddish brown to black squarish spots, rectangular bars or comma-shaped streaks. 3 yellow, orange or tan bands may underly spiral rows, below shoulder and on both sides of centre. Typical form (Pl. 10, Figs. 8-13) often with less densely spaced markings; occasionally, colour bands obsolete or covering large parts of last whorl. In form polyglotta (Pl. 10, Figs. 16-19), black bars or comma-like markings tend to fuse into solid narrow spiral bands and wavy axial streaks. Form crassus (Pl. 10, Figs. 14-15) has red-brown markings and usually lacks spiral colour bands. Larval whorls white. Teleoconch sutural ramps with reddish brown or blackish brown spots, axial streaks or blotches; intensity of spire pattern matching that of last whorl pattern. Aperture white.

Periostracum yellowish orange, thin, translucent, and smooth in subadult specimens, becoming olive-brown and less translucent in adults.

Dorsum of foot ivory, occasionally with beige lateral and posterior sides; marginal zone of central and posterior part with radial markings of grey, black and various shades of brown; anterior part often with 2-3 triangular grainy black blotches radiating from centre, and with 2 grey to black markings near anterior corners. Sole of foot uniformly ivory to pinkish beige, mottled white and tan, or buff with a darker yellow anterior edge. Rostrum pale pink or buff. Tentacles white, sometimes tan distally and dorsally. Distal part of siphon white, edged with pink, yellow or tan; central part tan or white, with 1 or 2 irregular black rings grading to grey latero-ventrally; proximal part light brown, mottled with darker brown and black dorsally (Pl. I, Fig. 19) (Chaberman, pers. comm., 1981; Estival, 1981; Kohn, unpubl. observ.; Pearson, pers. observ.). Typical form and form crassus have identical body colouration (Richards, pers. comm., 1989).

Radula teeth with an adapical barb opposite a large blade; short serration from the end of the barb to the end of the blade; base with a spur (Rola'n, pers. observ., 1991).

Habitat and Habits: Intertidal to about 65 m, mostly in 1-25 m. C. eburneus lives primarly in and on sand bottoms of subtidal reef flats, in sand-filled channels, large patches of sand and among weed on sandy or muddy substrate (Cernohorsky, 1964 & 1978; Kohn & Nybakken, 1975; Kohn, 1981; Reichelt & Kohn, 1985; Tirard, pers. comm., 1989). In East New Britain, Richards (pers. comm., 1989) has observed that typical C. eburneus often lives in dense colonies in 1-20 m, while form crassus is solitary, usually half buried in volcanic sand close to gravel bottoms below 12 m. C. eburneus preys mainly on polychaetes belonging to several families and is also known to feed on fishes. Its venom is toxic to worms, mollusks and small fishes, less dangerous to small mammals (Endean & Rudkin, 1965; Kohn & Nybakken, 1975; Reichelt & Kohn, 1985; Thorsson, 1989). Egg diameter of 150 fm predicts a minimum pelagic period of about 28 days (Perron & Kohn, 1985).

Discussion: C. eburneus resembles C. litteratus and sometimes C. leopardus. C. litteratus differs in its larger size, sharply angulate shoulder, bluish brown pointed base, and less pronounced spiral sculpture of sutural ramps and last whorl; its last whorl is less convex below the shoulder and tends to be narrower. C. leopardus attains much larger size, usually has a more angulate shoulder and weak basal ribs (in contrast to more pronounced ribs and ribbons). Both species differ from C. eburneus in the colouration of the animal. C. eburneus also resembles C. tessulatus and C. suturatus; for comparison, see the DISCUSSIONS of these species. We consider C. crassus Sowerby to be a form or perhaps an ecotype of C. eburneus, but this remains a matter of dispute without conclusive evidence. Colour pattern intergrades are not known where both co-exist in the same locality with overlapping depth ranges; the slight differences in shell morphometry do not separate them. We consider C. eburneus var. polyglotta a colour form, as described by Weinkauff (1874).

Range Map Image

C. eburneus 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 Rckel, 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 Rckel, 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.

 

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