Whitesnout Guitarfish

Whitesnout Guitarfish, Rhinobatos leucorhynchus

The Whitesnout Guitarfish, Rhinobatos leucorhynchus, whose common Spanish name is guitarra trompa blanca, is a species in the Guitarfish or Rhinobatidae Family, known as guitarras in Mexico. There are twenty nine global members of the Rhinobatos Genus, of which two are found in Mexican waters of the Atlantic and four in Mexican waters of the Pacific.

The Whitesnout Guitarfish have shark-like bodies and large triangular heads that taper to a pointed blunt snout and incorporate the fused pectoral fins. Their discs are longer than they are wide. They are dark gray-brown in color with a few scattered spots on their back. Their snout is translucent and has a dark tip. Their ventral side is off-white. Their snout is moderately long with a blunt point and their mouth is straight with long oblique nostrils. Their snout has two cartilaginous ridges that are fairly wide apart and converge at the front. They have a small spiracle behind each eye, with two folds in the rear border. Their body is smooth to the touch, with a series of small spines along the middle of their back, a single group on each shoulder, and a few above each eye and around their spiracles. Their caudal fin is asymmetrical and without a distinct lower lobe. They have two large triangular-shaped dorsal fins of equal size that originate behind their pectoral fins.

The Whitesnout Guitarfish are bottom dwellers found in shallow coastal waters over sandy and muddy bottoms in bays and estuaries at depths up to 165 feet. They reach a maximum of 70 cm (28 inches) in length and 3.2 kg (7.0 pounds) in weight. They consume a wide variety of crustaceans and small fish. They are masters at camouflage and have the ability to rapidly change colors to match their substrate. Reproduction is via yolk sac with offspring born alive in litter sizes of four to twenty-eight.

In Mexican waters the Whitesnout Guitarfish are found in all waters of the Pacific with the exception that they are absent from Guerrero Negro northward along the central and northwest coasts of Baja.

The Whitesnout Guitarfish are very similar in size and shape to several other Guitarfish but they are only one of two species that have a translucent or semi-translucent snout. The Speckled Guitarfish, Rhinobatos glaucostigma, has slate gray spots on its head and upper body and parallel non-converging cartilaginous ridges on its snout, which distinguishes it from the Whitesnout Guitarfish.

The Whitesnout Guitarfish are caught primarily as a by-catch of benthic fisheries. They have been utilized as food by Native Americans for centuries although currently their food value is considered of very marginal quality. They are normally returned to the sea but some are retained and made into fish meal. They are considered harmless to humans.

Whitesnout Guitarfish (1)

Whitesnout Guitarfish (2)

Whitesnout Guitarfish (3)

Whitesnout Guitarfish, Juvenile, Rhinobatos leucorhynchus: Provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2013. Length: 21 cm (8.3 inches). Note that the underside of the snout is dusky which we believe is one present in juveniles. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.
Whitesnout Guitarfish, Juvenile, Rhinobatos leucorhynchus: Provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, August 2013. Length: 21 cm (8.3 inches). Note that the underside of the snout is dusky which we believe is one present in juveniles. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.
Whitesnout Guitarfish, Rhinobatos leucorhynchus: Fish caught out of coastal waters La Bocana, Baja California Sur, October 2015. Length: 66 cm (26 inches). Catch and photo courtesy of George Brinkman, Guelph, Ontario, Canada
Whitesnout Guitarfish, Rhinobatos leucorhynchus: Fish caught out of coastal waters La Bocana, Baja California Sur, October 2015. Length: 66 cm (26 inches). Catch and photo courtesy of Jeff Dawson, Joseph, Oregon.