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The Conus Biodiversity Website

CATALOGUE OF RECENT AND FOSSIL CONUS

  Conus loroisii Kiener, 1846.

Range: India and Sri Lanka eastwards to Philippines, Papua New Guinea and Solomon Islands.

Description: Medium-sized to large, solid to heavy. Last whorl usually ventricosely conical to broadly ventricosely conical; outline convex adapically, straight towards base. Aperture almost uniform in width. Shoulder subangulate to rounded. Spire usually low, sometimes of moderate height; outline variably concave. Teleoconch sutural ramps flat to slightly concave or faintly convex, with closely spaced spiral striae. Basal third of last whorl with variably spaced spiral grooves separating ribs and ribbons. Form insignis with a sometimes lower spire, a less rounded shoulder and sometimes pyriform subadults. Form huberorum smaller and lighter in weight. Last whorl ventricosely conical to distorted conoid-cylindrical with straighter outline. In distorted specimens, aperture wider at base than near shoulder. Spire of low to moderate height, outline slightly sigmoid to concave; in distorted specimens, early postnuclear whorls stepped.

Shell Morphometry
  L 50-120 mm
  RW 0.40-2.10 g/mm
     (L 50-100 mm)
  RD 0.66-0.76
  PMD 0.77-0.86
  RSH 0.03-0.09

Ground colour grey mixed with pale blue, tan to brown and sometimes darker violet. Colours arranged in blending spiral and axial zones. Last whorl with contrasting light narrow spiral bands at shoulder and below centre; shoulder band always present but often very narrow and inconspicuous; subcentral band may be absent or faint. Solid or interrupted reddish to blackish brown lines occur infrequently on last whorl. Base of columella and siphonal fasciole partially or completely brown to dark violet-brown. Early teleoconch sutural ramps brown; later ramps match last whorl in colouration, with obsolete to fairly distinct brown radial streaks. Aperture usually white to bluish white, sometimes orange. Periostracum brown, fairly thick, and opaque, with raised spiral ridges (Kohn, 1978) or tufted spiral lines (India). In form huberorum, ground colour grades to darker olive-grey with a greater number of more pronounced violet or brownish violet axial zones on last whorl and axial streaks on later sutural ramps. Shoulder band often darker than in typical form, shading from creamy grey to pale violet grey; subcentral band often obscured or absent. Dashed or dotted spiral lines on last whorl as rare as in typical form. Colouration of aperture usually darker than in typical form. In form insignis, last whorl tinged with whitish to bluish or greenish grey, or various shades of brown; colours arranged in blending spiral zones. Shoulder band usually pronounced, shading from milky white to light brown or violet-grey; subcentral band usually present, often somewhat wider than in other forms and similar to shoulder band in colour. Closely spaced and variably fine, blackish brown lines extend from base to shoulder band, usually faint or absent on basal fourth. Lines often with an alternation of reddish brown lines; occasionally, lines become dashed or dotted. Staining of columella and siphonal fasciole more pronounced than in other forms. Teleoconch sutural ramps brown to blackish brown, either solidly coloured or irregularly streaked with shades of brown. Periostracum brown, thin and translucent, with widely set spiral rows of tufts (Philippines; Papua New Guinea). Typical form from India with an ovately triangular operculum. Foot chocolate brown, darker on sole. Siphon buff, mottled with grey on proximal part and with broad longitudinal dorsal and lateral bands of black and dark grey on distal part (Kohn, 1978). In N. New Guinea, dorsum of foot dark greyish violet, broadly edged with ivory grey and with black dots clustering on posterior part, in anterior corners and along the lateral sides of an ivory grey area anterior to the rostrum; anterior edge with an orange spot at centre. Sole of foot purplish beige, edged with dark violet. Rostrum grey, becoming progressively darker proximally; tip cream. Tentacles purplish grey. Siphon greyish violet, darker dorsally and distally; tip mostly black, sometimes white (animals probably representing C. l. form insignis; Chaberman, pers. comm., 1981).

Habitat and Habits: In 5 to 70 m; reported from sandy bottoms. Typical form found in depths of 9 - 18 m; form huberorum known from depths between 35 and 70 m. Specimens from India are known to feed on polychaetes (Kohn, 1978).

Discussion: Specimens of C. loroisii with dashed spiral lines resemble C. glaucus. in colour pattern. The latter species is of smaller size, its ground colour is rather bluish grey than brownish grey, the radial blotches on its sutural ramps are darker and rather separate than confluent, and the spiral lines on its last whorl consist of smaller and more separate markings. For comparison between C. loroisii and C. figulinus, see the DISCUSSION of the latter species. C. huberorum is considered to represent an ecological form of C. loroisii, because both intergrade in shape and colour pattern. This form is sympatric with the typical form along the Coromandel coast but has a different bathymetric range. Distortion during growth causes the differences in relative diameter spire height. Dautzenberg`s var. insignis and typical C. loroisii are almost identical in shell morphometry and differ only in colour pattern. Specimens with and without closely spaced spiral lines occur sympatrically both in the Bay of Bengal and in Philippines. Lineate specimens intergrade with typical non-lineate C. loroisii in the former region; in the Philippines, the lineate pattern of var. insignis may be reduced. These data strongly suggest that var. insignis is a variant of C. loroisii. Tucker (1984) separates C. loroisii and var. insignis on the subspecies level but intergradation in Philippines and the absence of geographic variation does not support this. For different taxonomic views, see Walls (1979: var. insignis and C. loroisii attached to C. figulinus); Coomans et al. (1979: C. loroisii assigned to C. figulinus); Tucker (1984: C. figulinus separated from C. buxeus; the latter species with 2 subspecies: C. b. loroisii and C. b. buxeus (= var. insignis)); Richard (1990: C. loroisii as a valid species; var. insignis assigned to C. figulinus; C. huberorum as a valid species).

Range Map Image

C. loroisii 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.

 

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