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The Conus Biodiversity Website

CATALOGUE OF RECENT AND FOSSIL CONUS

  Conus hyaena Hwass in Bruguière, 1792.

Range: C. h. hyaena from India and Sri Lanka eastwards to Indonesia and in the South China Sea northwards to Hong Kong; C. h. concolor known from the Solomon Is. and Papua New Guinea, recently reported from the Indonesian area.

Description: Medium-sized to moderately large, moderately solid to solid. Last whorl conical to ventricosely conical, sometimes approaching pyriform; outline variably convex adapically, less so or straight below; left side concave near base. Shoulder angulate to rounded. Spire of low to moderate height, outline straight to slightly concave or sigmoid. Early postnuclear whorls weakly tuberculate. Teleoconch sutural ramps flat to convex, with 2 increasing to 6-8 (occasionally to 10-11) spiral grooves, often obsolete on latest ramps. Last whorl with variably distinct wrinkled spiral ribs at base. C. h. concolor differs from C. h. hyaena in an usually straighter outline of the last whorl, a consistently angulate shoulder and a consistently low spire.

Shell Morphometry
  L 40-73 mm
     (India; 39-50 mm Indonesia)
  RW 0.17-0.53 g/mm
     (India; 0.15-0.26 g/mm Indonesia)
  RD 0.61-0.71
     (India; 0.55-0.67 Indonesia)
  PMD 0.78-0.86
     (India; 0.79-0.88 Indonesia)
  RSH 0.09-0.18
     (India; 0.11-0.14 Indonesia)

In C. h. hyaena, ground colour white to bluish grey, variably overlaid with various shades of brown or yellowish orange. Axially streaked or spirally banded shells intergrade with nearly solidly coloured ones. Often, dashed or almost solid brown lines around last whorl. Larval whorls beige to pale brown. Teleoconch sutural ramps irregularly or axially streaked, matching last whorl in colouration. Aperture white to bluish white behind a translucent marginal zone, occasionally pale violet deep within. Periostracum yellowish or orangish brown to dark brown, moderately thick, opaque, with interlaced axial ridges and 10-18 widely and almost equally spaced often tufted spiral ridges on last whorl incl. shoulder. C. h. concolor chocolate brown to almost black, sometimes mid- brown or olivaceous. Occasionally last whorl either maculated with lighter axial streaks or encircled with faint rows of darker dots. Larval whorls beige or pale pink; adjacent teleoconch sutural ramps light brown. Periostracum brownish grey, thin, translucent, with interlaced axial ridges and 6-10 widely spaced tufted spiral ridges on last whorl. In N.W. India, sole of foot greyish brown, streaked with darker grey; sides of foot brown, anterior edge buff. Rostrum pale reddish brown, grading to buff posteriorly. Tentacles white with a grey dorsal streak. Siphon tipped with black, grading to greyish black or grey posteriorly (Kohn, 1978 & unpubl. observ.). Operculum elongately paddle-shaped (length ratio operculum/shell 0.185). Da Motta (1983) described the animal of C. halli as similar in colour; the operculum is stoutly paddle-shaped (length ratio operculum/shell 0.150). In N.W. Borneo, animal pinkish white to pinkish or creamy orange, with reddish tones usually more distinct on foot; siphon tipped with light to dark red (Lace, pers. comm., 1989). In C. h. concolor, operculum small and ovate (length ratio operculum/shell 0.110). In N.W. India, Java and Solomon Islands, radular teeth of 1-1.5 % of the shell length, with an adapical barb opposed to a blade; serration of 22 - 37 denticles extends backwards almost to the middle of the shaft, terminating in a well-separated cusp; shaft waisted just posterior to the cusp, base with a strong prominent spur. Specimens from Java agreeing with the description of C. halli have fewer but stronger denticles than specimens in N.W. India (22 - 26 vs. 32 - 37); specimens of C. h. concolor are intermediate in number of denticles (27 - 29).

Habitat and Habits: Intertidal and upper subtidal; C. h. hyaena common in intertidal and slightly subtidal habitats, with deeper populations (to 50 m) known only from S. India; C. h. concolor subtidal between 3 and 30 m. C. h. hyaena inhabits fine sand to coarse gravel or rock in intertidal habitats at Bombay (Kohn, 1978), coral rubble with sparse eel-grass vegetation within a "mangrove and coral shore-line of sandy mud" at Pasir Putih (Java; da Motta, 1983), and rock crevices or silty sand beneath dead coral slabs at N.W. Borneo (Lace, pers. comm., 1989). C. h. concolor is found on flats of coarse sand and on mud, often beneath rotting plants (Rckel & Korn, 1992). In shallow-water habitats near Bombay, C. h. hyaena feeds on errant polychaetes mainly of the family Onuphidae but also Eunicidae and Nereidae (Kohn, 1978).

Discussion: C. biliosus, occurring sympatrically with C. h. hyaena in India and Indonesia, differs from the latter in its tuberculate late teleoconch whorls (often including shoulder), different colour pattern of both shell and animal and in its different ecological attributes. C. biliosus from India has a straighter outline in its last whorl; Indonesian shells of C. biliosus have a broader last whorl than sympatric specimens of C. h. hyaena (0.65-0.76 vs. 0.58-0.67). C. h. concolor resembles the sympatric C. gilvus, which can be separated by its smaller size, usually broader last whorl (0.59-0.66 vs. 0.56-0.62) and by the smaller number of spiral grooves on its late sutural ramps. Indian shells of C. h. hyaena tend to grow larger and have a broader last whorl than those from Indonesia. Some authors (da Motta, 1985; Richard, 1990) separate them as a distinct species (C. mutabilis) from the Indonesian C. hyaena (also described as C. halli). However, neither the type specimens of C. mutabilis, C. hyaena and C. halli nor specimens from the two regions can be clearly distinguished by conchological characters. There is a considerable overlap in shell morphometry and colour pattern between the western and the eastern populations. In addition, the animals from Bombay and Java are very similar in colouration and have only minor differences in radular tooth morphology. We therefore consider both populations to represent geographical variants of the same taxon. In addition, shells from Hong Kong cannot be distinguished from the Indian shells (da Motta, 1985 & pers. comm.; Richard, 1990). The lectotype of C. concolor (RD 0.57; RSH 0.11) is in good accordance with shells from Solomon Is. and Papua New Guinea in shape and colouration (Rckel & Korn, 1992). These populations are considered to represent an eastern subspecies of C. hyaena (C. h. concolor). The Indonesian shells of C. h. hyaena overlap in morphometry with C. h. hyaena from India as well as with C. h. concolor. They include specimens with nearly straight last whorl outline and angulate shoulder as well as specimens with convex outline and subangulate shoulder. This gradual change from west to east is evidence against separation of C. h. concolor at the species level. The differences in shape of operculum and radular teeth and the minor differences in shell morphometry favour subspecies status, but more conclusive evaluation of all these populations will require additional analyses of characters and distribution.

Range Map Image

C. hyaena 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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