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The Conus Biodiversity Website


  Conus catus Hwass in Bruguière, 1792.

Range: Entire Indo-Pacific; in the Red Sea and Oman only form nigropunctatus.

Description: Moderately small to medium-sized, moderately solid to solid; relative weight of similarly sized specimens may vary by 40%. Last whorl usually ventricosely conical to broadly and ventricosely conical; outline variably convex adapically and mostly straight below; left side occasionally sigmoid. Shoulder angulate to rounded. Spire of low to moderate height, outline slightly concave to slightly convex. Larval shell multispiral, maximum diameter 0.6-0.7 mm. First 2-3 postnuclear whorls tuberculate. Teleoconch sutural ramps flat to slightly concave, with 1 increasing to 4-8 spiral grooves; latest ramps with additional subsutural spiral striae. Last whorl variable in spiral sculpture. Shells with well separated, weak spiral ribs on basal third vary continuously with shells having strong, variably broad ribs or ribbons, usually minutely to strongly granulose and often with 1-2 fine smooth ribs in between, from base to shoulder. Form nigropunctatus (Pl. 15, Figs. 24-27) with a slightly less solid shell. Last whorl entricosely conical or conoidcylindrical. Spire outline either straight or slightly convex. First 3-5 postnuclear whorls tuberculate. Late sutural ramps with 5-6 spiral grooves. Last whorl consistently with a few well separate spiral ribs near base.

Shell Morphometry
  L 25-52 mm
     (-form nigropunctatus 30-50 mm)
  RW 0.15-0.50 g/mm
     (-form nigropunctatus 0.13-0.34 g/mm)
  RD 0.62-0.78
     (-form nigropunctatus 0.61-0.68 mm)
  PMD 0.78-0.87
     (-form nigropunctatus 0.76-0.85 mm)
  RSH 0.10-0.19

Ground colour white to bluish grey. Pattern of last whorl variable in colour, arrangement and extent. Colour ranges from yellowish brown to olive-brown, blackish brown and orange or red. Shells with sparse small flecks on each side of centre intergrade with solidly dark shells except for a narrow spiral ground-colour band at centre. Surface pattern emphasized by bluish grey or brownish violet background clouds. Spiral rows of brown dots and dashes extend from base to shoulder, either containing intermittent white markings or fusing into solid dark lines. Rows variably spaced and ranging from complete absence to dominant pattern element. Larval whorls usually red, less frequently white to brown. Teleoconch sutural ramps with radial streaks or confluent blotches that match pattern elements of last whorl in colour. Aperture white or cream.
Periostracum yellowish brown, smooth, varying in thickness as well as in translucency (Kohn, 1959a, 1978a; Cemohorsky, 1964).
Form nigropunctatus with a more greyish ground. Pattern of last whorl consists of light to blackish brown surface clouds and blue-grey background clouds. Clouds usually aligned in a spiral row on each side of centre, sometimes absent or fusing into large solid zones. Spiral rows of dots and dashes always pronounced, with regularly or irregularly intermittent white markings. Apex pink to orange. Early postnuclear sutural ramps with regularly spaced dark brown dots at outer margin; in late whorls, dots sparse or missing, additional brown radial streaks or blotches often present. Aperture white.
Periostracum yellow, thin, translucent, smooth.

Periostracum yellowish brown, smooth, varying in thickness as well as in translucency (Kohn, 1959a, 1978a; Cemohorsky, 1964). Periostracum yellow, thin, translucent, smooth.

In typical form, foot grey to pale brown; dorsum variously mottled with tan to blackish brown, darker anteriorly; sole usually mottled with brown, occasionally immaculate and brighter at ends. Rostrum white to buff, mottled or longitudinally streaked with brown, more densely proximally. Tentacles white. Siphon white to grey, sometimes grading to buff or brown on dorsal side of proximal portion; mottled with brown, more heavily dorsally and proximally (PI. 75, Fig. 30; PI. 79, Second row, middle and right) (Kohn, 1959a, 1978a & unpubl. observ.; Chaberman, pers. comm., 198 1); form nigropunctatus matching typical form in colour pattern (Fainzilberet al., 1992); in form morrisoni, body colouration similar except tip of siphon pink to orange (G. Raybaudi, 1991).

In typical form, radular teeth with 3 strong barbs adapically, with a recurved tip on posterior barb; neither serration nor basal spur present (Peile, 1939; James, 1980; Kohn, unpubl. observ.; Nybakken, 1990).

Habitat and Habits: Intertidal to about 20 m; in protected and exposed sites on benches, rocky shores and subtidal coral reef flats, occupying crevices, pockets or patches of sand with or without vegetation, bare limestone, algal turf and coral rubble. On intertidal benches, the peak density of animals is found halfway across the habitat (Kohn, 1959a, b, 1960, 1978a; Kohn & Nybakken, 1975: Cernohorsky, 1964; Huish, 1978; Kay, 1979; Estival, I981 ; Grosch, pers. comm., 1989). Form nigropunctatus on coral reefs on sand bottom near coral rubble or buried amongst eel-grass roots (Sharabati, 1984; Fainzilber et al., 1992). Form morrisoni reported in 3-5 m, in channels on coarse sand and rubble among live coral (G. Raybaudi, 1991). Typical form of C. catus and form nigropunctatus feed on small fishes. The venom is toxic to fishes and small mammals but has no effects on invertebrates; it may be dangerous to man (Kohn, 1959b; Endean & Rudkin, 1963: Fainzilber et al., 1992). Egg capsules with a tall stalk. In Hawaii, capsules of 10- 12 x 8.5- 10 mm contain an average of 1,650 eggs. Egg diameter is 220 µm in Hawaii, 231 µm in Palau and 241 µm in the E. Indian Ocean, suggesting minimal pelagic periods of 22, 20 or 19 days (Kohn, 1961a; Perron & Kohn, 1985).

Discussion: C. catus is allied to C. achatinus, C. monachus and C. striolatus. C. achatinus attains larger size, has a less solid shell and more tuberculate postnuclear whorls. It has usually a narrower last whorl (RD 0.54-0.69) and its periostracum has tufted spiral ridges and fringed shoulders. C. striolatus tends to have a more ovate last whorl (PMD 0.7 1-0.80) than C. catus and lacks tuberculate early postnuclear whorls. Both C. achatinus and C. striolatus can also be distinguished from C. catus by their animals having a large saddle-shaped black blotch on the anterior dorsum of the foot. C. monachus has a less solid shell, attains larger size but has a relatively narrower last whorl, and usually has a more angulate shoulder as well as weaker spiral sculpture on the late sutural ramps. Moreover, it is set apart by its nebulose pattern and its darker larval shell. For comparison of C. catus with C. cocceus, see the Discussion of the latter species.
C. nigropunctatus is considered a distinct species by Coomans et al. (1985b) and Richard (1990), and as a variety of C. catus by E. A. Smith (1891). Specimens from Red Sea and Oman and Mozambique conforming to its description intergrade with typical C. catus from the W. Indian Ocean in all conchological characters. C. morrisoni (Pl. 15, Fig. 28) is considered as a distinctively coloured local form of C. catus (pattern orange to red) from Ashmore Reef in the Timor Sea and from Thevenard Id., W. Australia. The synonyms of typical C. catus refer to infrasubspecific forms, which are not restricted geographically. C. discrepans and C. purus seem to refer to completely white shells, and C. reflexus is based on a shell with sparse orange flecks on a white ground.

Range Map Image

C. catus 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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