Calliostoma annulatum

Jeweled Topsnail
Calliostoma annulatum crawling on a kelp leaf
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Vetigastropoda
Superfamily: Trochoidea
Family: Calliostomatidae
Subfamily: Calliostomatinae
Genus: Calliostoma
Species: C. annulatum
Binomial name
Calliostoma annulatum
(Lightfoot, 1786)
Synonyms
  • Trochus annulatus Martyn, 1784
  • Trochus moniliferus Phil.
  • Trochus virgineus Chemnitz
  • Zizyphinus annulatus Martyn, Reeve,

Calliostoma annulatum, also known as the purple-ring topsnail, blue-ring topsnail or jeweled topsnail, is a medium-sized sea snail with gills and an operculum.[1]

This is a sublittoral marine gastropod mollusk in the family Calliostomatidae. This snail lives off of the Pacific coast of North America.

Range of distribution

This top shell can be found in the littoral zone from Isla San Geronimo, Baja California, north to Forrester Island, Alaska.

Shell description

The shell height varies between 16 mm and 35 mm. The elevated-conic shell is imperforate and rather thin. This species is distinguished by its brilliantly colored shell, which is lustrous with a gold field, dotted with brown on the spiral rows of grains, the periphery or lower edge of each whorl encircled by a zone of violet or magenta stripes, the axis surrounded by a tract of the same. The brilliance of the colors fades somewhat once the animal dies. The thin shell shows numerous granulose spiral riblets, about 7 on the penultimate whorl, 9 or 10 on the base. It has few or none interstitial lirulae. The acute, reddish apex is minute. The sutures are slightly impressed. There are about 9 whorls, slightly convex, the last angular at periphery, flattened beneath. The rhomboidal aperture is oblique, fluted within. There is no umbilicus.[2] The head and foot of the animal has a yellow-orange color with brown spots. This animal has a light amount of gold on its back so poachers like to capture them.

Life habits

This species is fairly omnivorous, feeding seasonally on kelp, sessile fauna like bryozoans, and detritus.

Two individuals of Calliostoma annulatum are visible on this hydrocoral

References

  1. Rosenberg, G. (2012). Calliostoma annulatum (Lightfoot, 1786). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=534197 on 2012-12-10
  2. Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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