Source: Nature (via UASR)
Date: 24 September 98
Written by: P. Forey (Natural History Museum London, UK), Mark V. Erdmann (Univ. of Calif)

The coelacanth is a primitive *teleost fish that apparently first appeared in the *Devonian Period, with the most recent fossil specimens dating from the *Cretaceous Period. The group was assumed to be extinct, but a living specimen was caught in 1938 in the mouth of the Chalumna River in South Africa and named Latimeria chalumnae. The 1938 specimen was 2 meters in length and weighed 40 kilograms. Several more specimens have since been caught, all off the coast of South Africa and near the island of Madagascar (Comoros archipelago) in the Indian Ocean.

M.V. Erdmann et al now report the capture and observation of a live coelacanth specimen near the island of Manado Tua (north Sulawesi) in Indonesia on 30 July 1998. The Indonesian specimen was caught in a net at a depth of 100 to 150 meters. The specimen is 1.24 meters in length and weighs 29.2 kilograms, and the authors report it was observed by them live for more than 3 hours before the carcass was deep frozen and tissue samples collected for molecular analysis. The authors suggest that interviews with the local fishermen, and the vast distance from the Comoros archipelago to Indonesia (approximately 10,000 kilometers), strongly support the idea that the Indonesian coelacanths (which are evidently well known in the region and called "raja laut" or King of the Sea) are part of an established north Sulawesi coelacanth population and not simply strays. Like its Indian Ocean counterpart, the Indonesian coelacanth was found in the vicinity of oceanic volcanic caves, its presumed habitat.

In a companion article concerning the M.V. Erdmann et al paper, P. Forey makes the following points: 1) Before the 1938 discovery, the date of the youngest coelacanth fossil recovered was approximately 80 million years ago. This raises the question of how the lineage survived for that time without leaving any trace in the fossil record. 2) The theory of relationships prevalent in the late 1930s held that the coelacanth was a direct descendant of Devonian fish-like ancestors of land-living vertebrates (tetrapods), but from modern evolutionary analysis it seems that coelacanths are more distantly related to land-living vertebrates, and that lungfishes are the closest living relatives to the tetrapods. 3) Significant in the coelacanth are paired fins that move in a manner unlike that seen in most fishes but in a manner identical to limb movement in vertebrates. There are also sensory structures in the coelacanth that are apparently precursors of structures responsible for hearing in air. The author concludes: "The new discovery underlines how little we really know about the coelacanth in particular and oceanic life in general."

A home from home for coelacanths. Peter Forey, plf@nhm.ac.uk

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