Marine biologists have discovered a new species of the wrasse genus Iniistius living in the Indo-West Pacific Ocean.
The eclipse-spot razor wrasse (Iniistius bakunawa) from Panay Island, Philippines. Image credit: H. Motomura.
Iniistius is a small genus of razor wrasses native to the Indian and Pacific Oceans.
First established in 1862, the genus contains over 20 scientifically recognized species.
These wrasses have highly compressed bodies, a notch separating the first two dorsal-fin spines from the rest of the fin, and a steep forehead with a firm knife-like anterior edge — enabling them to easily dive into the sand when threatened.
Unlike their coral reef-associated relatives, they live almost exclusively in wide sandy habitats.
Since these habitats are often overlooked by divers, the biology and taxonomy of razor wrasses are poorly known.
“Wrasses of the genus Iniistius are medium to large fishes (usually between 10 and 35 cm in length),” said Kent Elson Sorgon from the University of the Philippines Los Baños and colleagues.
“They are frequently associated with sandy habitats such as sea-grass meadows or wide sand channels away from coral reefs.”
“Adults are usually modestly colored with pale reflective scales to match the sandy habitats in which they frequent.”
“In contrast, juveniles employ protective mimicry by mimicking dead leaves and other floating debris.”
“Very small juveniles are particularly convincing, adopting a languid, wafting style of swimming with their prolonged anterior dorsal-fin spines lending to a highly irregular silhouette.”
“When startled or in the presence of predators, they plunge headfirst into the substrate and bury themselves using rapid undulatory axial body movements.”
“Species of Iniistius are of small commercial interest and are taken as food fish throughout their range, though mostly by small scale artisanal fisheries in island nations.”
The researchers described the new species based on seven specimens from artisanal fish markets in the islands of Panay, Cebu, Bohol, and Jolo in the Philippines, and two specimens trawled from the Dampier Archipelago, Western Australia at depths of 54-57 m (177-187 feet).
Named Iniistius bakunawa (or the eclipse-spot razor wrasse), this fish is between 15 and 17 cm (5.9-6.7 inches) long.
It resembles other members of the genus in coloration, but differs in having a pale yellowish to jade green body and a white oval spot with a black central spot on the rearmost edge of its dorsal fin.
It is likely that Iniistius bakunawa occurs elsewhere in the Indo-West Pacific, particularly between Philippines and Western Australia.
“New species continue to be described annually, some from colorful adventures, others from unexpected places like a public market on a humid noon in April,” the researchers said.
“Much remains to be explored about these wrasses and other fishes that live in seemingly barren areas like sandy habitats.”
“Their presence in wet markets speaks to the diversity of fisheries in the Coral Triangle, which makes basic research such as taxonomy even more important to better understand how we can manage our natural resources.”
“All in all, we are still gnawing at the surface of the astounding diversity of fishes, and a species completely new to science might be on your dinner plate right now.”
The discovery of Iniistius bakunawa is reported in a paper published online in the Raffles Bulletin of Zoology.
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Kent Elson S. Sorgon et al. Iniistius bakunawa, a new species of razor wrasse (Teleostei: Labridae) from the Philippines and Western Australia. Raffles Bulletin of Zoology 71: 511-519; doi: 10.26107/RBZ-2023-0038
