- Named the Halichoeres sanchezior the tailspot wrasse, a colorful new species of fish has been found living on rubble in the waters surrounding the Revillagigedo Archipelago.
- The island system is known as the “Mexican Galapagos” for its vast marine biodiversity.
- “It’s amazing that we can still find species that are new to science in a place that people often visit — it just shows how big and complex the world is,” said Ben Frable of UC’s Scripps Institution of Oceanography San Diego.
SAN DIEGO (KSWB/KUSI) — Researchers say they discovered a new species of tropical fish during an expedition to remote islands off the Pacific coast of Mexico.
Named the Halichoeres sanchezior the tailspot wrasse, the colorful species was found living among volcanic rubble in the waters surrounding the Revillagigedo Archipelago — an island system known as the “Mexican Galapagos” for its vast marine biodiversity.
The discovery was officially entered into the scientific record on Tuesday with the publication of a paper on the species in the journal PeerJ.
“It’s amazing that we can still find species that are new to science in a place that people often visit — it just shows how big and complex the world is,” said Ben Frable of UC’s Scripps Institution of Oceanography San Diego, which is one. of the scientists on the expedition.
Based on specimens examined by Frable and the rest of the team, the species range in size from about an inch long to about six inches, Scripps said. They are also believed to be hermaphroditic, beginning life as female with some eventually transitioning to male.
Smaller female fish are mostly white with reddish horizontal stripes along their top half and black spots on their dorsal fin, behind their gills and just in front of their tail fin. The male fish was described by Frable as having “orangey red above fading to a yellow belly with a dark band at the base of the tail.”
According to Scripps, researchers believe they are related to other fish in the wrasse family, such as the California sheephead and bluestreak cleaner wrasse, both pictured below. However, the species is believed to be endemic, meaning it is unique to the area and not found anywhere else on Earth.
Located 250 miles south of the Baja California peninsula, the Revillagigedo islands are known for their abundance of marine life, due in part to protections that prevent fishing in the area.
This preservation of the island’s aquatic biosphere regularly attracts recreational scuba divers and scientists, offering them a “window back to a time before intensive fishing,” as Frable describes it.
Compared to other islands, however, Revillagigedo’s underwater wildlife remains poorly studied. According to Scripps, the last rigorous scientific survey of the island’s fish species took place more than two decades ago.
That lapse prompted marine scientist Carlos Armando Sánchez Ortíz of the Universidad Autónoma de Baja California Sur to mount the latest expedition with a team of international researchers in November 2022, leading to the discovery of the tailspot wrasse.
Over the course of the two-week excursion, the group, which included dozens of underwater researchers and photographers, explored all four islands in the Revillagigedo system on 30 different research dives, collecting of more than 900 specimens representing more than 100 species of fish.
As Frable recalled, the team encountered a tailspot wrasse on the last day of the trip when Sánchez collected a small, red fish in the water off San Benedicto Island about 70 feet below the surface without really knowing what it was.
Back on the boat, Frable said they realized the specimen was a type of wrasse and matched a photo of a fish of an unknown species captured by a diver in 2013.
On one of the last dives of the expedition, Frable found another species of this fish, but it slipped through the team’s nets. However, on the last dive of the trip, Frable and the National History Museum of Los Angeles County’s William Lundt recovered another specimen.
According to Scripps, DNA analysis confirmed that the fish are part of a district species, bringing the total number of endemic fish species for the Revillagigedo Archipelago to 14.
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