First identified in 1997 and officially classified as a distinct species in 1999, the Indonesian coelacanth (Latimeria menadoensis) is one of only two extant species of coelacanths. This deep-sea fish closely resembles its ancient Cretaceous ancestors.
A deep diver approximately 1 meter behind the Indonesian coelacanth (Latimeria menadoensis) was found at a depth of 144 m in Northern Mark, Indonesia. Image credit: Alexis Chappuis.
Coelacanths belong to the group of fish known as Sarcopterygians and are characterized by their distinctive coastal dwelling.
Long believed extinct for 65 million years, coelacanths were serendipitously rediscovered in 1938 off the coast of South Africa by museum curators and local fishermen.
These fascinating fish possess unique features, including paired fins and lobed fins that resemble highly modified swim bladders.
Together with lungfish, they are among the closest living relatives to tetrapods, exhibiting several morphological traits not present in more distantly related vertebrates, like ray-finned fish.
The coelacanth first appeared in the early Devonian period, gradually diversifying during the Devonian and Carboniferous periods, with peak diversity observed in the early Triassic.
During the Cretaceous, they were classified into two families: the Latimeridae, which has survived as two species in the genus Latimeria, and the now-extinct Mawsoniidae.
Upon the discovery of the first living specimen, its resemblance to many fossilized forms from the Cretaceous period led to it being labeled a “living fossil,” indicating minimal evolutionary change over millions of years.
The two extant species are the coelacanth of the West Indian Ocean (Latimeria chalumnae) found near the Comoros Islands, and the coelacanth in the waters around Sulawesi, Indonesia.
The latter species is far better documented than its African counterpart, making its deep-reef habitat challenging to access for scientific observation, which has primarily relied on submersibles or remotely operated vehicles (ROVs).
Left profile of the Indonesian coelacanth (Latimeria menadoensis), showcasing a unique pattern of white dots. Image credit: Alexis Chappuis.
The Indonesian coelacanth is a rarely documented medium-deep sea fish (non-tetrapod sarcopterygian), originally endemic to the Sulawesi region, primarily identified through bycatch in eastern Indonesia.
“Very few observations of this species have been made in situ, primarily using submersibles and ROVs.”
“The first direct in situ observations were reported following recent reconnaissance dives that explored the suspected habitat of the Indonesian coelacanth at depths exceeding 150 meters.”
Researchers encountered the Indonesian coelacanth in October 2024 during a deep dive in the Marc Archipelago, situated between Sulawesi and Western New Guinea.
“It is premature to assess the population of this newly identified Malukan coelacanth,” they stated.
“Since the Marc Archipelago connects Sulawesi and Western New Guinea, it suggests that the species is not confined to a single location.”
“Our recent findings, along with studies conducted in the mesophotic coral ecosystems of the Marc Archipelago since 2022, not only confirm the existence of Latimeria but also indicate a broader, more suitable habitat for coelacanths.”
“We hope this discovery will motivate local and national authorities to enhance conservation efforts in this biodiversity-rich region.
The research team’s paper was published online on April 23, 2025, in the journal Scientific Reports.
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A. Chapuis et al. 2025. The first record of a living coelacanth from Northern Mark, Indonesia. Sci Rep 15, 14074; doi:10.1038/s41598-025-90287-7
Source: www.sci.news
