Bowmouth guitarfish

What it is

This ray possesses a robust, thick body that distinguishes it from many other elasmobranchs. Its head features a rounded snout and a unique mouth shaped like a wavy letter W. The dorsal surface displays a bluish-gray to brown coloration covered in white spots, along with prominent black markings above the pectoral fins. A row of sharp thorns runs down the center of its back, providing protection against predators. Adults can grow quite large, reaching lengths of nearly three meters and weights over one hundred kilograms.

Where it lives

The species inhabits tropical coastal zones throughout the western Indo-Pacific region. Its distribution stretches from the Red Sea and South Africa across the Indian Ocean to Southeast Asia and Western Australia. In the Pacific, populations extend northward to Japan and southward to New South Wales. Individuals typically reside near the seabed in sandy or muddy environments, occasionally visiting rocky reefs or shipwrecks at depths ranging from shallow waters to ninety meters.

How it lives

Bowmouth guitarfish are powerful swimmers that propel themselves using their tails, similar to sharks. They exhibit nocturnal activity patterns and do not establish territorial ranges. Their diet consists primarily of bottom-dwelling fish, crabs, shrimp, and mollusks, which they crush using flattened teeth. While generally non-territorial, they defend themselves against threats like tiger sharks using their dorsal thorns and aggressive ramming behavior.

Breeding and life cycle

Reproduction occurs through viviparity, where embryos develop internally and receive nourishment from yolk reserves. Females give birth to live young, with litter sizes varying between two and eleven pups. Newborns measure approximately forty-five to fifty-one centimeters in length. Sexual maturity is reached at different sizes for males and females, with females growing larger than their male counterparts throughout their lives.

Fish and people

Fisheries target this species for its valuable fins used in soup and its meat, which is sold fresh or dried. Trawlers often view the animal as a nuisance because its rough skin and bulk damage nets during capture. Conservation efforts include captive breeding programs at aquariums in Kentucky and Singapore, which have successfully raised pups in captivity. Traditional uses also include crafting bracelets from the ray's enlarged thorns in Thailand.

Status and threats

The International Union for Conservation of Nature lists this species as Critically Endangered due to intense fishing pressure. Population numbers have dropped significantly in regions like Indonesia, where unregulated gillnet fisheries operate. Habitat degradation from blast fishing and siltation further threatens survival. Although some Australian waters show a Near Threatened status, the global population remains at high risk of extinction without effective management strategies.

Relatives and look-alikes

Evolutionary relationships within rays remain debated, though morphological evidence suggests closeness to wedgefishes and sawfishes. Genetic studies indicate it forms a group with Rhynchobatus and Rhynchorhina. Historically classified in various orders, modern taxonomy places it in Rhinidae. It is sometimes confused with other guitarfishes due to shared shark-like fins, but its distinct thorny ridges and mouth shape set it apart.

Questions people ask about Bowmouth guitarfish

Good reading and sources

• Rhina ancylostomus on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data