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The Conus Biodiversity Website

CATALOGUE OF RECENT AND FOSSIL CONUS

  Conus spectrum Linnaeus, 1758.

Range: Indonesia to Philippines and Ryukyu Is., to Australia and Papua New Guinea.

Description: Medium-sized to moderately large and moderately light to solid, relative weight of similarly sized specimens may vary by 50%; form pica (Plate 41, Figs. 9-12) moderately small to medium-sized and moderately solid. Last whorl usually ventricosely conical, occasionally conoid-cylindrical or ovate; outline convex adapically, less so to straight below; left side usually concave above prominent siphonal fasciole, seldom so in form pica. Aperture wider at base than near shoulder. Shoulder angulate to subangulate. Spire low, outline concave. Larval shell of 2.25-2.75 whorls; maximum diameter 0.8-1.1 mm, 0.8-0.9 mm in form pica. Early postnuclear whorls occasionally undulate to weakly tuberculate. Teleoconch sutural ramps almost flat, with 0-2 increasing to 3-5 equal or to 7-8 variably broad spiral grooves; elevations between usually as well separated ribs, grading to spirally striate, closely spaced ribbons in form pica. Last whorl with variably spaced spiral ribs and ribbons separated by grooves on basal third to half, sometimes followed by spiral threads to shoulder; in form pica, spiral sculpture more uniform, with ribs anteriorly, then a few ribbons, and smooth above.

Shell Morphometry
  L 30-76 mm
     (-form pica 30-42 mm)
  RW 0.08-0.50 mm
     (L 35-69 mm; -form pica 0.12-0.22)
  RD 0.51-0.67
     (-form pica 0.59-0.67)
  PMD 0.73-0.86
  RSH 0.03-0.12
     (-form pica 0.07-0.11)

Ground colour white. Last whorl usually with yellowish orange to dark brown axial streaks, flames and blotches, generally concentrated or fused into 2-3 interrupted or solid spiral bands. White shells intergrade with brown shells with a paler central band; shells with an irregularly arranged pattern intergrade with shells with a regularly reticulate pattern between the spiral bands. Some specimens also with wavy or straight, continuous or discontinuous brown axial lines from base to shoulder or shoulder ramp; some with closely spaced, dotted to solid spiral lines. In form pica, pattern consists of separate spots to confluent blotches; widely spaced dotted spiral lines in some shells; traces of axial lines rarely present. Larval whorls white to pale brown, white in form pica. Late sutural ramps with narrow to broad and confluent radial markings matching last whorl pattern in colour; shells with an immaculate white spire intergrade with shells with a nearly brown spire. Aperture generally white to bluish white and often slightly translucent.

Periostracum pale olive-grey, thin, translucent, and smooth but darker, thicker and with interlaced axial ridges in form pica.

In W. Australia, animal pale cream, maculated with light brown; foot thinly edged with black (Turnbull, pers. comm., 1987). In E. Australia, sole and sides of foot white; dorsum of foot laterally edged with a fine black line that expands into a spot anteriorly; siphon white, with immaculate tip and brown transverse lines proximally (Kohn, unpubl. observ.). In the Timor Sea, dorsum of foot with a narrow black pre-marginal band expanding into a blotch at each comer of both ends (G. Raybaudi Massilia, pers. comm., 1992).

Habitat and Habits: Intertidal to about 50 m, mainly on sand. In W. Australia on intertidal and slightly subtidal sand bars to sand bottoms in about 40 m (Turnbull, pers. comm., 1987).

Discussion: C. spectrum resembles C. wittigi, C. broderipii, C. fischoederi, and C. blanfordianus. C. wittigi is a smaller species (L 26-42 mm) with an often higher spire (RSH 0.07-0.17), and a reticulate pattern with triangular markings rather than axial markings on the last whorl. C. broderipii has a less pronounced spiral sculpture on the late sutural ramps and a violet to purple aperture. The shells from Philippines provisionally assigned to C. broderipii differ in a generally higher spire (RSH 0.09-0.16), less angulate shoulder, pale brown spiral background bands, and a rose, orange or violet aperture. C. fischoederi is distinguished from C. spectrum by its higher spire (RSH 0.11- 0.17) with a less concave outline and more prominent shoulder tubercles in the early postnuclear whorls and by the absence of spiral ribbons basally on the last whorl. Variants of C. spectrum from Moluccas (form conspersus) and Philippines are particularly similar to C. fischoederi in their last whorl pattern with dashed to solid brown spiral lines. However, they differ in their wider apertures and smoother last whorls; in form conspersus, the aperture is often suffused with flesh to pale orange and the last whorl pattern lacks tentmarks. C. blanfordianus differs mainly in its colour pattern: White with about 15 spiral rows of brown spots and bars. C. spectrum as presented here exhibits considerable conchological variability both within and between populations. It may represent a complex of closely related species, but we are unable to identify consistent differences in shape, sculpture and colour pattern among variants from different parts of its range. We thus favour the hypothesis of a single species. The representation of the lectotype of C. spectrum (Rumphius, 1705: Pl. 33 fig. s), probably from Moluccas, is moderately slender, low-spired and ornamented with axial streaks. We consider the following nominal species to be forms of C. spectrum: C. conspersus: Type specimens are no longer available. The figure of the holotype (Reeve, 1844: Pl. 47 sp. 262) lacks distinctive characters exept for the yellow colour. Reeve himself considered the holotype to be an "indifferent specimen" and figured afterwards (1849: Suppl. Pl. 9 sp. 262b) a more distinctive specimen "encircled throughout with fine close-set hair lines and with a warm flesh tint" within the aperture. Similar specimens occur in the Moluccas intergrading with typical C. spectrum (Coomans et al.; 1985a). We therefore provisionally consider C. conspersus a colour form of C. spectrum, although the absence of type specimens does not allow unequivocal assignment (Pl. 41, Figs. 19, 20). C. daphne: Shell ventricosely conical to ovate; solid yellow, encircled with fine brown lines on the last whorl and a wider line at the shoulder (Pl. 41, Figs. 22-25). The aperture is yellowish pink, similar to that of C. conspersus. Richard (1990) considered C. daphne a valid species; we provisionally consider it a local form with a restricted distribution in Indonesia. C. dolium: Last whorl rather broad and ventricose, with large, variably confluent orange-brown areas; its spire is remarkably low (Pl. 41, Fig. 26). This form occurs in Philippines and is very similar to form pica. C. filamentosus: Known only from the holotype, which probably represents a subadult specimen, (Pl. 41, Figs. 29, 30). It has a yellowish brown last whorl, flecked with white below shoulder and centre, and with spiral grooves up to the shoulder. Its slender shape and rather narrow aperture resemble attributes also found in subadult and adult specimens of other variants. We provisionally attach C. filamentosus to C. spectrum. C. lacteus: It is usually considered to be conspecific with C. parius. The lectotype (Pl. 47, Fig. 27) is white, has widely spaced spiral grooves from the base to the subangulate shoulder and a relatively low spire. C. parius differs in its more rounded shoulder and its generally weak spiral sculpture on the late sutural ramps, except for a distinct adaxial groove. A larger specimen of C. lacteus also present in the MHNG (coll. Delessert) (Pl. 41, Fig. 28) is more distinct in its resemblance to C. spectrum and in its difference from C. parius. We thus consider C. lacteus a form of C. spectrum. C. pica: A distinctive variant very similar to form dolium (Pl. 41, Figs. 9-12). Its sympatric occurrence in the Philippines and differences from other variants of C. spectrum suggest distinction at the species level. However, as specimens conforming with the description of C. pica overlap with C. spectrum in all studied shell characters, we provisionally consider them conspecific. C. verreauxii: The identity of the figured shell (Pl. 41, Fig. 21) from Cape of Good Hope is dubious. It resembles C. conspersus in the fine brown spiral lines and scattered small brown spots on the last whorl. Reeve was the first to suggest that C. verreauxii is identical with C. conspersus, although Kiener compared it with C. anemone. Whether this hypothesis is correct or C. verreauxii represents a valid species, cannot be unequivocally decided, because we lack a type specimen and the original figure shows the dorsal side of the shell only. We provisionally follow Reeve's suggestion and regard C. verreauxii as a synonym of C. spectrum form conspersus (cf. Coomans et al., 1985a). C. stillatus: Last whorl with fine dark brown axial lines (Pl. 41, Figs. 17, 18). C. carota represents a synonym rather than a form of C. spectrum.

Range Map Image

C. spectrum 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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