Range: New Caledonia, Norfolk Is., Kermadecs Is. and Northern Three Kings Rise (28° 40' S, 173° E).
Description: Moderately small to medium sized, light to moderately solid. Last whorl conical, outline straight, slightly convex at adapical fourth. Shoulder angulate. Spire of low to moderate height, outline concave. Larval shell of about 3.25 whorls, maximum diameter about 1.1 mm. First 3-4 postnuclear whorls tuberculate. Teleoconch sutural ramps flat to slightly concave, with 0-4 increasing to 5-7 spiral grooves. Last whorl with a few weak spiral ribs and grooves at base.
| Shell Morphometry | ||
|---|---|---|
| L | 20-61 mm | |
| RW | 0.05-0.26 g/mm | |
| (L 20-54 mm) | ||
| RD | 0.58-0.65 | |
| PMD | 0.86-0.94 | |
| RSH | 0.02-0.15 | |
Ground colour white. Last whorl with about 9 broad brown spiral lines from base to adapical third or fourth, widely spaced basally and rather closely spaced adapically. Posterior lines within a variably broad light to reddish brown spiral band above centre. Widely but unevenly spaced brown axial lines and streaks connecting the brown spiral lines and extending from the adapical band to the shoulder ramp. Larval whorls and first 2-3 postnuclear sutural ramps white to beige. Following sutural ramps with brown radial lines. Aperture white.
Periostracum light brown, thin, translucent.
Habitat and Habits: In New Caledonian waters, in 225-365 m; in 135-154 m at Raoul Id., Kermadec Is. The deepest record, 844 m, is from Northern Three Kings Rise.
Discussion: C. plinthis is similar to C. capitanellus, sympatric with C. plinthis in the New Caledonian area. It differs from C. plinthis in its broader last whorl(RD 0.60-0.71), the presence of two brown spiral bands, and in the absence of brown axial and spiral lines on the last whorl.
C. plinthis 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.