Strikingly beautiful fairy wrasse discovered in the Maldives

The Maldives, a group of 26 atoll islands in the Indian Ocean, are home to a stunning array of tropical reef fish, along with a diversity of other fish, including rays and sharks. The known fish fauna total over 1,100 different species, a biodiversity that far exceeds that found in other marine regions. And now there is a brand new species to add to the list – a rose-veiled fairy wrasse, Cirrhilabrus finifenmaa.

This brightly colored reef fish is remarkable not only for its stunning beauty, but also because its discovery marks some noteworthy “firsts.” It is the first species to be given a name derived from the local Dhivehi language. Its specific name, “finifenmaa” means “rose,” and refers both to its pink coloration and to the island nation’s national flower. It is also the first time that local Maldivian scientists have been involved in the formal description process of a new species from the local marine environment.

“It has always been foreign scientists who have described species found in the Maldives, without much involvement from local scientists, even those species that are endemic to the Maldives,” said study co-author Ahmed Najeeb, a biologist at the Maldives Marine Research Institute (MMI). “This time it is different and getting to be part of something for the first time has been really exciting, especially having the opportunity to work alongside top ichthyologists on such an elegant and beautiful species.” 

The new fairy wrasse species was actually first collected by researchers in the 1990s. However, at that time it was thought to be the adult form of a different species, Cirrhilabrus rubrisquamis, which had been described in 1983 based on a single juvenile specimen from the Chagos Archipelago, an island chain 1,000 kilometers (621 miles) south of the Maldives. Subsequently, more specimens thought to be C. rubrisquamis were collected from the Maldives and, although scientists now assumed they had examples of adult males and females, there remained confusion about the appearance of the juvenile fish. 

In order to clear up the confusion, scientists from the California Academy of Sciences, the University of Sydney, the MMRI, and the Field Museum collaborated to re-evaluate the species as part of the Hope for Reefs initiative, aimed at better understanding and protecting coral reefs around the world. 

The team conducted a very detailed analysis of the anatomy and morphology of both adult and juvenile examples of the beautiful, multicolored fish. This involved measuring the lengths of spines supporting the fins, counting scales on different body regions and measuring the dimensions of the body parts – including the head, jaw, and tail. 

The magenta and peach coloration was also described in detail for all the specimens. These data, along with genetic analyses, were then compared to data from the original C. rubrisquamis specimen to confirm that what the scientists had was indeed a unique species, C. finifenmaa.

One important consequence of describing C. finifenmaa as a new species is that the known ranges of the two different wrasse species now become greatly reduced. Instead of there being one species distributed all the way between the Maldives and the Chagos Archipelago, 1,000 kilometers to the south, each fairy wrasse species is now known from only one of the island groups. This is a crucial consideration when planning conservation and management strategies.  

“What we previously thought was one widespread species of fish, is actually two different species, each with a potentially much more restricted distribution,” said lead author and University of Sydney doctoral student Yi-Kai Tea. “This exemplifies why describing new species, and taxonomy in general, is important for conservation and biodiversity management.” 

Sadly, populations of the beautiful rose-veiled fairy wrasse may already be under threat. Even though this species has only just been described to science, it is already being exploited for sale to aquarium enthusiasts around the world. 

“Though the species is quite abundant and therefore not currently at a high risk of overexploitation, it’s still unsettling when a fish is already being commercialized before it even has a scientific name,” said senior author Dr. Luiz Rocha, who co-directs the Hope for Reefs initiative. “It speaks to how much biodiversity there is still left to be described from coral reef ecosystems.” 

Marine scientists from the MMRI have continued their collaboration with the Hope for Reefs researchers by conducting the first surveys of the Maldives’ “twilight zone” reefs. These virtually unexplored coral ecosystems are found between 50 and 150 meters (160–500 feet) beneath the ocean’s surface. Last month’s survey enabled the researchers to collect new specimens of C. finifenmaa, along with at least eight potentially new-to-science species yet to be described. 

This sort of collaborative endeavor between international partners is key to understanding the Maldives’ coral reefs and ensuring they are adequately conserved into the future. 

“Nobody knows these waters better than the Maldivian people,” said Dr. Rocha. “Our research is stronger when it’s done in collaboration with local researchers and divers. I’m excited to continue our relationship with MMRI and the Ministry of Fisheries, to learn about and protect the island nation’s reefs together.”

“Collaborating with organizations such as the Academy helps us build our local capacity to expand knowledge in this field. This is just the start and we are already working together on future projects,” said Najeeb. “Our partnership will help us better understand the unexplored depths of our marine ecosystems and their inhabitants. The more we understand and the more compelling scientific evidence we can gather, the better we can protect them.”

The study is published in the journal ZooKeys.

Image Credit: © Yi-Kai Tea

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By Alison Bosman, Earth.com Staff Writer