First discovered in 1997 and described as a new species two years later, the Indonesian coelacanth (Latimeria menadoensis) is one of two living species of coelacanth, a deep-sea fish that closely resembles its ancestors from the Cretaceous period.
Deep diver about a meter behind the Indonesian coelacanth (Latimeria menadoensis) discovered at a depth of 144 m in North Maluku, Indonesia. Image credit: Alexis Chappuis.
Coelacanths are a group of large, sea-cave dwelling lobe-finned fish (sarcopterygians).
They were thought to be extinct for 65 million years, until a first living specimen was discovered fortuitously in South Africa in 1938 by a South African museum curator on a local fishing trawler.
Coelacanths present several unique and intriguing features such as unpaired lobbed-fins looking much like paired fins and highly modified lungs/swim bladder.
Together with lungfish, they are the closest relatives to tetrapods and share with them several morpho-anatomical features that are not found in more distantly related vertebrates such as ray-finned fishes.
Coelacanths first appeared in the Early Devonian epoch, diversified a little in the Devonian and Carboniferous period, and attained a maximum of diversity in the Early Triassic.
During the Cretaceous period, they are known by two families only, the Latimeriidae, which survived to the present with two species in the genus Latimeria, and the Mawsoniidae, which went extinct at the end of the Cretaceous.
When the first living specimen was discovered, it reminded so much fossil forms from the Cretaceous that it was designated as a ‘living fossil,’ i.e. a species with a morphology that did not evolve much over a long period of time.
The two living species are the West Indian Ocean coelacanth (Latimeria chalumnae) form the Comoros Islands off the east coast of Africa, and the Indonesian coelacanth from the waters off Sulawesi, Indonesia.
The latter species has been much less documented than its African congener, and due to the difficulty of reaching the deep-reef habitats it lives in, very few observations were made, and only from submersibles or Remotely Operated Vehicles (ROVs).
Left profile of the Indonesian coelacanth (Latimeria menadoensis), with its unique pattern of white dots. Image credit: Alexis Chappuis.
“The Indonesian coelacanth is a rarely-documented, moderate deep-water lobe-finned fish (non-tetrapod sarcopterygian) initially thought to be endemic to the Sulawesi region of Indonesia and known primarily from bycatch,” said Alexis Chappuis, a researcher at the Association UNSEEN (Underwater Scientific Exploration for Education) the Centre for Collaborative Research on Aquatic Ecosystems in Eastern Indonesia, and colleagues.
“Very few direct in situ observations have been made of this species, and only using submersibles and ROVs.”
“We report the first direct in situ sightings by divers of a live specimen of the Indonesian coelacanth in the waters of North Maluku, Indonesia, during recent reconnaissance technical dives exceeding 150 m depth to investigate suspected coelacanth habitats.”
The researchers encountered Indonesian coelacanths in October 2024 during deep dives in the waters of the Maluku archipelago, which is located between Sulawesi and Western New Guinea.
“It is too early to discuss a new Malukan coelacanth population,” they said.
“Still, since the Maluku archipelago is located between Sulawesi and Western New Guinea, it is unlikely that only one individual lives in this broad region.”
“Our recent sightings, combined with the work we have conducted on mesophotic coral ecosystems of the Maluku archipelago since 2022, not only confirm the presence of Latimeria but also, more widely, the existence of suitable coelacanth habitats.”
“Meanwhile, we hope this discovery will encourage local and national authorities to increase conservation efforts in this vibrant and biodiverse region, which is now confirmed to be hosting one of the most elusive and emblematic marine species found in Indonesian waters.”
The team’s paper was published online April 23, 2025 in the journal Scientific Reports.
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A. Chappuis et al. 2025. First record of a living coelacanth from North Maluku, Indonesia. Sci Rep 15, 14074; doi: 10.1038/s41598-025-90287-7