Toothed Flounder

Toothed Flounder, Cyclopsetta querna

Toothed Flounder, Cyclopsetta querna, Larval Form. Photograph provided by the commercial fishermen of Todos Santos, September 2014. Length: 14 cm (5.5 inches). Tentative identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, California and reconfirmed by Dr. Benjamin Victor, www.coralreeffish.com.

Toothed Flounder, Cyclopsetta querna. Fish caugth from coastal waters off Point Palmilla, Baja California Sur, November 2020. Length: 39 cm (15 inches). Photograph immediately above is of the atypical gill rakers of this species.

Toothed Flounder, Cyclopsetta querna. Fish caught from coastal waters off San Bruno, Baja California Sur, June 2020. Length: 41 cm (16 inches). Catch and photographs courtesy of Chris Wheaton, Fullerton, California. Note: this is a very difficult identification and their is a 50% chance that this is a Panamic Flounder, Cyclopsetta panamensis.

The Toothed Flounder, Cyclopsetta querna, is a member of the Sand Flounder or Paralichthyidae Family, and known in Mexico as lenguado dientón. Globally, there are five members of the genus  Cyclopsetta, of which four are found in Mexican waters, two in the Atlantic and two in the Pacific Ocean.

The Toothed Flounder is a flatfish has an elongated oval body with a depth that is 42% to 46% of standard length. Their eye side is dark brown with a few lighter crossbars. There are 2 or 3 large black spots on their anal and dorsal fins and a dark blotch in the middle of their caudal fin. Their blind side is off-white. They have a small rounded head with a short snout and a large mouth that ends behind the rear edge of their eyes. Their eyes are large and located on the left side (with a small percentage being right-eyed), elevated, parallel, and separated by a flat space. They have one row of immovable teeth on both jaws and a pair of canines at the front of their top jaw (after which they are named). Their anal fin has 70 to 74 anal rays; their caudal fin is short and pointed with a wide base; and, their dorsal fin has 89 to 93 rays and originates before the top eye. They have 7 to 10 very short, fat, and most unusually-shaped gill rakers on their lower arch (pictured above – see the Dappled Flounder for more traditionally-shaped gill rakers). They are covered with small smooth scales on both eye and blind sides and their lateral line is straight and originates just behind the eyes and extends to the caudal base.

The Toothed Flounder is a demersal species that is found over and within sandy and muddy bottoms at depths up to 90 m (300 feet). They are known to enter brackish waters. They reach a maximum of 44 cm (17 inches) in length, as established by a fish in my possession. As of January 1, 2023, the International Game Fish Association world record stood at 0.91 kg (2 lbs 0 oz) with the fish caught in coastal waters off Puerto Vallarta, Guerrero in May 2013. 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. The Toothed Flounder is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Toothed Flounder is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from Magdalena Bay, Baja California Sur, northward along the central and northwest coasts of Baja.

The Toothed Flounder is most likely confused with the Beach Flounder, Syacium latifrons (smaller – maximum length 25 cm (10 inches), lacks highly visible teeth); they can also be confused with the California Halibut, Paralichthys californicus (arched lateral line; doubly concave caudal fin, 25 to 32 gill rakers), the Cortez Halibut, Paralichtys aestuarius (arched lateral line; 24 to 31 gill rakers), the Dappled Flounder Paralichthys woolmani (arched lateral line; 16 to 20 gill rakers), and the Panamic Flounder, Cyclopsetta panamensis (rough eye side scales).

From a conservation perspective the Toothed Flounder has not been formally evaluated. They are considered to be an excellent food fish, however they are uncommon and seldom seen by humans. They are normally caught as a by-catch of deep water shrimp trawls taken over sand and mud substrate.