Fantail Sole, Xystreurys liolepis
The Fantail Sole, Xystreurys liolepis, whose common Spanish name is lenguado cola de abanico, is a member of the Sand Flounder or Paralichthyidae Family, known collectively as lenguados areneros in Mexico. Globally, there are only two members of the genus Xystreurys, one of which, this species from Mexican waters of the Pacific.
The Fantail Soles are left-eyed and right-eyed flat fish with a strongly arched lateral line that extends into their head and branches into their lower eye. They have elongated bodies with a depth that is 50 to 55% of standard length. Their eye side has a uniform pale gray-brown coloration with several small dark brown and white spots. Most fish have two large dark spots, one on the lateral line above their arch and the other at the base of their caudal fin. Their anal and caudal fins have dark spots and their long pectoral fins have dark bars. Their blind side is off-white. They have a small head with a short snout and a small mouth that ends under the middle of their lower eye. Their eyes are large, elevated, and set close together. Their top eye occurs before their lower eye. They have one row of small conical teeth on each jaw. They have 57 to 62 anal rays and 73 to 80 dorsal rays. Their dorsal fin originates over the top eye. Their caudal fin (for which they are named) is slightly rounded, the pectoral fin on their eye side is equal to or longer than the head, and their pelvic fins are symmetric. They have two plus 6 or 7 short fat gill rakers on their lower arch and are covered with a mixture or small and large scales.
The Fantail Soles are bottom dwellers found over and within sandy and muddy bottoms at depths up to 445 feet. They reach a maximum length of 53 cm (21 inches). They are opportunistic and well-camouflaged ambush predators that lie in wait half submerged on the ocean floor. They prey on small fish and a wide variety of crustaceans.
In Mexican waters the Fantail Soles are found along the entire west coast of Baja and throughout the Sea of Cortez. They are absent from coastal waters south of Mazatlán.
The Fantail Sole can be confused with the California Halibut, Paralichthys californicus (body depth 38–40% of length; doubly concave caudal fin) and the Longfin Sanddab, Citharichthys xanthostigma (17 or 18 gill rakers; maximum length 25 cm).
The Fantail Sole is considered to be an excellent food fish and sold commercially but on a limited basis. They are also caught from boats by recreational anglers.
Fantail Sole, Xystreurys liolepis, right eyed. Fish caught in coastal waters off Catalina Island, California, September 2017. Length: 29 cm (12 inches). Catch, photo and identification courtesy of Chris Wheaton, Fullerton, CA.
Fantail Sole, Xystreurys liolepis, left eyed. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Length: 20.1 cm (7.9 inches). Photo and identification courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.