Orange-spotted Sand Perch, Diplectrum eumelum
The Orange-spotted Sand Perch, Diplectrum eumelum, whose common Spanish name is serrano carabonita, is a species in the Sea Bass or Serranidae Family, known collectively as serranos in Mexico. Globally, there are twelve species in the genus Diplectrum, ten of which are found in Mexican waters, two in the Atlantic and eight in the Pacific.
The Orange-spotted Sand Perches have elongated bodies with an overall gray-brown color with gold speckling with five to eight indistinct narrow dark bars on the sides. They have three to five orange spots along the cheek that join an orange bar that angles from the eye down across the gill cover. There are also orange spots behind the eye and on the gill cover. The caudal fin has vertical rows of small orange spots and there is a black blotch at its base. They have white anal fins with yellow marks and yellow pectoral and pelvic fins. The dorsal fin has a black margin with the spiny portion being dusky, and the second part having two orange stripes that transition to spots at the rear. Their head has a blunt snout and a narrow bony cheek spur (preoperclum) with eight to fourteen long spines (pictured below); the shape of their head is a key to identification. All their fins are transparent with the exception of the upper portions of their caudal fin and their pectoral fins, which are yellow.
The Orange-spotted Sand Perches are found over sandy bottoms at depths between 35 and 330 feet. They reach a maximum length of 31 cm (12 inches). They are a small and rare deep water species and very little is known about their behavioral patterns.
In Mexican waters the Orange-spotted Sand Perch are found from Magdalena Bay southward along the southwest coast of Baja, in the southern three-fourths of the Sea of Cortez, and along the coastal mainland south to Guatemala.
The Orange-spotted Sand Perch is difficult to correctly identify because there are eight very similar Sand Perches, all of the Diplectrum Genus, living in Mexican waters of the Pacific. The key to a correct identification is the unique shape of the preoperculum. See Sand Perch Preoperclum for an interesting side-by-side look at some fish anatomy of seven very similar looking fishes of the Diplectrum Genus found in the Pacific.
The Orange-spotted Sand Perch is too small and too rare to be of interest to most.