Chagos Brain Coral
CR

Chagos Brain Coral

Ctenella chagius

Declining

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Ctenella

Overview

Ctenella is a monotypic genus of stony coral in the family Euphylliidae. It is represented by a single species, Ctenella chagius. These corals are massive in size with meandering valleys between the calyces which have solid, non-porous walls and fine, evenly spaced, solid septae. They are found in the Indian Ocean being endemic to the Chagos Archipelago. It forms solid, smooth hemispherical domes.

Ctenella chagius faces severe threats from military activities and restricted access to its habitat on Diego Garcia, which limits conservation monitoring and management. The species' extremely limited range makes it vulnerable to any environmental changes or disturbances within the Chagos Archipelago. Ocean acidification and rising sea temperatures pose additional risks to the marine ecosystems this gastropod depends upon.

Threat summary

Habitat

This marine gastropod is endemic to the shallow coastal waters and coral reef environments around Diego Garcia in the Chagos Archipelago, British Indian Ocean Territory. It inhabits tropical marine ecosystems characterized by coral formations and associated benthic communities.

Marine coastal/supratidal· majorWetlands (inland) - Permanent freshwater lakes· majorMarine neritic· major

Conservation measures underway

Species managementSpecies recoveryEx-situ conservationLegislation

Other threatened species in EUPHYLLIIDAE

EN

Euphyllia baliensis

Declining

Threatened in British Indian Ocean Territory

Far Eastern CurlewEN

Far Eastern Curlew

Numenius madagascariensis

Declining
Spinetail Devil RayCR

Spinetail Devil Ray

Mobula mobular

Declining
African Wild AssEN

African Wild Ass

Equus asinus

Unknown
EN

Montipora caliculata

Declining

Frequently asked questions

Why is Chagos Brain Coral classified as Critically Endangered?
Chagos Brain Coral is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Ctenella chagius faces severe threats from military activities and restricted access to its habitat on Diego Garcia, which limits conservation monitoring and management. The species' extremely limited range makes it vulnerable to any environmental changes or disturbances within the Chagos Archipelago. Ocean acidification and rising sea temperatures pose additional risks to the marine ecosystems this gastropod depends upon.
Where does Chagos Brain Coral live?
Chagos Brain Coral occurs in British Indian Ocean Territory, Maldives, Mauritius, Papua New Guinea, Réunion, and Seychelles. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Chagos Brain Coral?
The main threats to Chagos Brain Coral are 5.4, 6.2, 9.3.4, and ai-1. The full IUCN-classified threat record for this species is detailed on the species page.

Get weekly conservation intelligence

One short digest a week of the most striking species and country data we ship, plus breaking conservation news paired with our database where it matters.

Free, no spam. One-click unsubscribe in every email.