Ocellated Waspfish

The genus Apistus is a monotypic category within the marine ray-finned fish, classified under the subfamily Apistinae, commonly known as wasp scorpionfishes, which is part of the family Scorpaenidae, encompassing scorpionfishes and their relatives. The sole species within this genus is Apistus carinatus, which is known by several common names, including ocellated waspfish, bearded waspfish, longfin waspfish, and ringtailed cardinalfish. This species exhibits a broad distribution across the Indo-Pacific region and is characterized by venomous spines located within its fins.

The genus Apistus was originally described in 1829 by the French zoologist Georges Cuvier. During his documentation, Cuvier described the species Apistus alatus, which was later designated as the type species of the genus in 1876 by Pieter Bleeker. However, A. alatus is recognized as a junior synonym of A. carinatus, initially described by German naturalists Marcus Elieser Bloch and Johann Gottlob Schneider in 1801 as Scorpaena carinata. The designated type locality for this species is Tranquebar in 🇮🇳 India. Within the Scorpaenidae family, the genus Apistus is classified under the subfamily Apistinae. The name "Apistus" translates to "untrustworthy" or "perfidious," as explained by Cuvier, due to the long and mobile spines around the eyes that serve as unexpected defensive weapons. The specific epithet "carinatus" means "keeled," likely referencing the bony ridges on the head.

Apistus carinatus possesses a moderately elongated and compressed body. The lateral head surface is fortified with bony ridges or keels, and the posterior pectoral-fin ray is distinct from the remainder of the fin. The dorsal fin comprises 14 to 16 spines and 8 to 10 soft rays, while the anal fin includes 3 or 4 spines and 6 to 8 soft rays. The species exhibits a bluish to pinkish-grey coloration with a prominent black ocellus on the posterior portion of the dorsal fin. Its long pectoral fins are notably yellow, and the chin features sensory barbels. The ocellated waspfish reaches a maximum total length of 20 cm (7.9 inches), although a more common size is approximately 10 cm (3.9 inches).

Apistus carinatus is widely distributed across the 🇮🇳 Indian and 🌊 Pacific Oceans. Its range extends from the 🌊 Red Sea along the eastern coast of Africa to 🇿🇦 South Africa, eastwards along the shoreline of the Arabian Sea, and into the Andaman Sea, reaching the 🌊 Pacific Ocean as far as the 🇵🇭 Philippines, northward to the Bonin Islands and the waters surrounding Kyushu, 🇯🇵 Japan, and southward to 🇦🇺 Australia. In 🇦🇺 Australian waters, the species is found from Shark Bay in Western Australia, along the northern coast, and extending south to off Newcastle in New South Wales on the east coast. This demersal fish inhabits depths of 14 to 16 meters (46 to 52 feet), although it is more typically found at depths ranging from 15 to 50 meters (49 to 164 feet) on sandy or silty substrates.

Apistus carinatus is a nocturnal predator that remains buried in the sand during the day, with only its eyes exposed. When disturbed, it extends its long, brightly colored yellow pectoral fins to ward off predators. These fins are also used to corner prey, and the sensitive chin barbels detect prey hidden in sand or mud. The spines on the dorsal and anal fins are equipped with a venom gland.

As a small-sized, venomous fish, Apistus carinatus holds limited commercial interest for fisheries. However, it is occasionally caught in trawl nets in the 🌊 Persian Gulf and, at times, in seine nets. In 🇦🇺 Australia, it is often encountered as bycatch in prawn fisheries.