Harpago chiragra
A large Indo-Pacific conch with six curved marginal digitations.
The Chiragra spider conch, *Harpago chiragra*, is a large marine gastropod mollusk belonging to the Strombidae family. Its shell is very thick, robust, and heavy, featuring a distinct anterior notch. The most striking trait is the six long, curved projections (digitations) that extend from the flaring outer lip and canals. The columella and aperture are lined with fine ridges (lirate). Shell length ranges from 85 mm to 320 mm, typically around 170 mm.
Strong sexual dimorphism exists: females are usually much larger than males. This species is widely distributed across the Indo-Pacific, from the Aldabra Atoll, Chagos, Mauritius, Mozambique, Sri Lanka, and the Gulf of Bengal east to Polynesia. Its range extends north to Taiwan and southern Japan, and south to New Caledonia and Australia.
*Harpago chiragra* inhabits coral reef areas, found in littoral and sublittoral zones, tidal pools, and low tide levels down to about 25 meters. It is herbivorous, feeding on plants and algae. Humans collect it locally for food, as the flesh is edible, and its shell is used in shellcraft.
Quick Facts
- Genus
- Harpago
- Species
- chiragra
Facts from the source article.
Lore & Background
The shell of Harpago chiragra is very thick, robust, and heavy, with a distinct anterior notch. Its most prominent characteristic is the six long and curved marginal digitations expanded from the flaring, thick outer lip and canals. The columella and aperture are lirate. Sexual dimorphism is strongly present, with female individuals usually much larger than males.
This species is widely distributed in the Indo-Pacific, ranging from the Aldabra Atoll, Chagos, Mauritius, Mozambique, Sri Lanka and the Gulf of Bengal to eastern Polynesia. It ranges north as far as Taiwan and southern Japan, and south to New Caledonia and Australia. It lives in coral reef areas, in littoral and sublittoral zones, in tidal pools and low tide levels to a depth of around 25 m.
Harpago chiragra is known to be an herbivore, feeding on plants and algae. The flesh is edible and locally collected for food, and the shell is used in shellcraft.
Reader's Guide
Harpago chiragra holds significance as a large, visually striking member of the Strombidae family, recognized by its six long, curved digitations that extend from the outer lip. Its robust shell, reaching up to 320 mm, makes it a notable subject in shellcraft, where the shell is used for decorative purposes. The species is also locally collected for its edible flesh, indicating its role in subsistence or small-scale food gathering across its wide Indo-Pacific range. The strong sexual dimorphism, with females much larger than males, is a distinctive biological characteristic. Its habitat in coral reef areas, from tidal pools to depths of about 25 m, places it within accessible coastal zones. The distribution spans from East Africa and the Indian Ocean to eastern Polynesia, and from Taiwan and southern Japan to New Caledonia and Australia, reflecting a broad tropical and subtropical presence. The species' combination of size, distinctive morphology, and utility in both food and craft contributes to its recognition among marine snails.
Did You Know?
- The shell length of Harpago chiragra varies between 85 mm and 320 mm, usually to 170 mm.
- Female individuals are usually much larger than male individuals.
More in Marine Snails: Ceriths, Nassas and Conchs, Part 2 1-24
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