Most rays have skin that is either smooth or evenly rough. The bowmouth guitarfish instead carries distinct ridges of greatly enlarged thorns, one arching over each eye and further rows along the midline and shoulders. The arrangement is conspicuous enough to identify the species from a photograph of the head alone.
The jaws are equally specialised. Rather than pointed teeth, the mouth carries undulating pavements of ridged plates that grind rather than cut, matched to a diet of crustaceans and shelled molluscs taken from soft bottoms near reefs.
The combination of a large body, valuable fins and a heavy-set shape that snags in nets has been ruinous. The species is assessed as Critically Endangered, and although it breeds occasionally in public aquaria, captive reproduction is difficult and does not offset losses in the wild.