Gorgona Guitarfish, Pseudobatos prahli

Gorgona Guitarfish, Pseudobatos prahli. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2018. Photographs courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuatanejo.com.

Gorgona Guitarfish, Pseudobatos prahli. Underwater photographs taken in Zihuantanejo Bay, Guerrero, December 2020. Photographs courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuatanejo.com.

Gorgona Guitarfish, Pseudobatos prahli. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2022. Photographs courtesy of Maude Jette, Dive Zihuantanejo, www.Divezihuatanejo.com.

The Gorgona Guitarfish, Pseudobatos prahli, and is known in Mexico as guitarra de Gorgona, is a species in the Guitarfish or Rhionobatidae Family, known collectively as guitarras in Mexico. Globally there are eight members of the genus Pseudobatos, of which seven are found in Mexican waters, two in the Atlantic and five in the Pacific Ocean.

The Gorgona Guitarfish has a shark-like body and a large triangular head that tapers to a long, pointed snout that incorporate the fused pectoral fins. Their discs are similar in length and width. The dorsal side is brown with pale areas on each side of the rostral cartilages with approximately 80 small white spots covering the disc. The caudal fin is light brown with approximately 20 light brown blotches and the lower half has a yellow border, the dorsal fins are light brown, and the pectoral and pelvic fins have light brown borders. Their ventral side is off-white with black blotches at the tip of the snout and sides. Their head has 2 central cartilaginous ridges that widen at the front to form a round, spatula like tip, large spiracles with the rear borders having 2 folds the inner 1 of which is most developed. The caudal fin is asymmetrical without a lower lobe, the 2 dorsal fins are equal sized, and they have approximately 75 small spines that run from the nape to the origin of the first dorsal fin, several small spines on each shoulder, and small spines on the front edges of the eyes.

The Gorgona Guitarfish has been documented at depths between 12 m (40 feet) and 69 m (225 feet) over sandy and rocky substrate. They reach a maximum of 81 cm (2 feet 8 inches) in length. Reproduction is ovoviparious (aplacental viviparity) with embryos feeding initially on yolk and then receiving additional nourishment via indirect absorption of uterine flue enriched with fat, mucus and from their mothers, with offsprings born live. The Gorgona Guitarfish 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 Gorgona Guitarfish is a resident of Mexican waters of the Pacific Ocean but has a limited range being found only in coastal waters off the State of Oaxaca within the Golfo de Tehuantepec south to Guatemala. The first report of the presence of the species in Mexican waters was reported as recently as August 2018. The fish photographed above extends this known range northwards along the coast of mainland Mexico into the coastal waters of the State of Guerrero.

The Gorgona Guitarfish is a straight forward identification that cannot be confused with any other Guitarfish found in Mexican waters of the Pacific due to abundance of white spots that cover the dorsal side of the disc.

From a conservation perspective the Gorgona Guitarfish is currently considered as Data Deficient. They are thought to be “uncommon” and have been poorly documented and poorly studied.