Coelacanth

Coelacanths are a lineage of large, deep-water lobe-finned fish belonging to the order Coelacanthiformes within the class Sarcopterygii. The name derives from Greek roots meaning hollow spine. Living coelacanths comprise two species: Latimeria chalumnae, first described from a specimen off the coast of South Africa in 1938, and Latimeria menadoensis, discovered in 1997 near Sulawesi, Indonesia. They are often referred to as living fossils because their body plan resembles that of ancient sarcopterygian fishes.

Today, Latimeria chalumnae is found in the western Indian Ocean, around the Comoros, Madagascar, and parts of eastern Africa; Latimeria menadoensis inhabits deeper waters near Indonesia. They prefer dark, deep-sea habitats such as reef slopes, caves, and submarine canyons, typically at depths of about 100 to 700 meters.

Coelacanths have distinctive lobed pectoral and pelvic fins, which contain bones homologous to limb bones in land vertebrates. Their cosmoid scales and a rostral organ in the snout are notable features. They are generally slow-moving and can reach lengths of roughly 1.5 to 1.8 meters, with females often larger than males.

Reproduction is ovoviviparous; embryos develop inside eggs retained within the mother and are born as live young. Coelacanths tend to have long lifespans and late maturity, producing small litters, factors that contribute to their vulnerability in the face of overfishing and environmental change.

Conservation status for the two species is of concern in many parts of their range. Protection and ongoing research are important for understanding their biology, evolution, and the persistence of deep-sea ecosystems that support them.