Hornyhead Turbot, Pleuronichthys verticalis
The Hornyhead Turbot, Pleuronichthys verticalis, whose common Spanish name is platija cornuda is a member of the Righteye Flounder or Pleuronectidae Family, known collectively as platijas in Mexico. Globally, there are eight species in the genus Pleuronichthys, five of which are found in Mexican waters, all in the Pacific.
The Hornyhead Turbots have elongated oval fusiform highly compressed bodies that are widest in the middle; their body depth is 49 to 53% of standard length. They are dark brown to yellowish brown with irregularly-shaped dark marbled blotches and small cream colored spots. Their blind side is off-white. They have relatively large eyes on their right side with the top eye preceding the lower eye. They have a ridge between their eyes and a prominent sharp back-pointing spine at the rear end of the ridge, a key to identification. They have a small asymmetrical mouth. Their anal fin has 44 to 51 rays; their caudal fin is small and rounded with a wide base; their dorsal fin has 65 to 75 rays; their pectoral fin on the eye-side has 10 to 12 rays; and their pelvic fins are symmetrical and found on both sides of the body. They have 12 to 17 gill rakers and a straight lateral line that originates above their eyes.
The Hornyhead Turbots are found demersal over and within sandy and muddy bottoms at depths up to 1,625 feet. They reach a maximum length of 37 cm (15 inches). They are opportunistic well-camouflaged ambush predators that lie in wait half-submerged on the ocean floor consuming crustaceans and small fish.
In Mexican waters the Hornyhead Turbot have a limited distribution in waters of the Pacific being found from Magdalena Bay northward along the central and northwest coasts of Baja and in the northern third of the Sea of Cortez.
The Hornyhead Turbot can be confused with a series of other Righteye Flounders including the C-O Sole, Pleuronichthys coenosus, the Diamond Turbot, Pleuronichthys guttulatus, the Ocellated Turbot, Pleuronichthys ocellatus, and the Spotted Turbot, Pleuronichthys ritteri, but none have the mottled coloration or spine in front of the eyes.
The Hornyhead Turbot are caught primarily as a by-catch of deep water trawlers. They are very difficult to catch via hook and line due to their small mouths. They are a poorly documented and poorly studied species that is of limited interest to most.
Hornyhead Turbot, Pleuronichthys verticalis. Fish provided by the commercial fishermen of Bahía Kino, Sonora, March 2015. Lengths: 20.0 cm (7.9 inches). Photo courtesy of Maria Johnson, Prescott College Kino Bay Center, Kino Bay, Sonora.
Hornyhead Turbot, Pleuronichthys verticalis. Fish provided by the commercial fishermen of the greater Los Cabos area, July 2012. Length: 21.5 cm (8.5 inches). Note the significant loss of color of this long frozen fish and that the head spines have been removed. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.