Diodon liturosus Shaw, 1804

Common Name and Taxonomy

Diodon liturosus Shaw, 1804, commonly called the Black-blotched porcupinefish, is a medium-sized fish.

Size

It reaches a maximum length of 65 cm (26 in), while the average size most commonly observed is 45 cm (18 in).

Body and Head Shape

It has an elongated body, a spherical head with large round protruding eyes, and a large mouth that is rarely closed.

Fin Arrangement

It has large pectoral fins, no pelvic fins, and anal and dorsal fins positioned close to the caudal peduncle.

Swimming Fin Movement

The anal and dorsal fins move simultaneously when the fish swims.

Fin Coloration

All fins are a uniform white or yellowish tint with no spotting.

Skin and Spines

Its skin is smooth and firm, with scales modified into spines that point toward the back.

Body Color Pattern

Its body base color ranges from light brown to sandy yellow, with dark blotches outlined by white lines, and a pale ventral surface.

Similar Species Distinction

It can be confused with the long-spine porcupinefish, Diodon holocanthus, but the Black-blotched porcupinefish has much shorter spines and lacks a dark streak running between its eyes.

Inflation Defense

When threatened, the porcupinefish can inflate itself by swallowing water.

Spine and Volume Defense

This increases its body volume to deter predators, and it can also raise its spines for defense.

Toxin Presence

The species concentrates the powerful neurotoxin tetrodotoxin in parts of its body including the liver, skin, gonads, and viscera.

Toxin Function

This toxin acts as an additional defense to discourage potential predators.

Habitat Climate Range

The Black-blotched porcupinefish lives in tropical and subtropical waters.

Geographic Distribution

It occurs in the Indo-Pacific region from the eastern coasts of Africa to Japan, the Society Islands, and Western Australia, and also in the southeastern Atlantic Ocean off the coast of South Africa.

Adult Habitat and Depth

Adult individuals prefer lagoons, top reefs, and seaward coral or rocky reefs at depths between 1 and 90 m, though they are most often found between 15 and 30 m depth.