Chaetodon lunula

Family : Chaetodontidae

 

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Text © Giuseppe Mazza

 

 

English translation by Mario Beltramini

 

 

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The Raccoon butterflyfish (Chaetodon lunula) is active only by night © Giuseppe Mazza

The Raccoon butterflyfish ( Chaetodon lunula - Lacepède, 1802 ) belongs to the class of the Osteichthyes, the bony fishes, to the Actinopterygii, the ray-finned fishes, to the vast order of Perciformes and to the colorful family of Chaetodontidae.

The name of the genus comes from the Greek “chaite” = hair and “odous” = tooth, due to the “bristle-shaped teeth”.

The name of the species “lunula” comes from the Latin “luna” = moon, night, therefore, “small moon”, with reference to the black crescent it has on the eyes, followed by an analogous white pattern, and maybe also due to the fact that it is a nocturnal butterflyfish.

This characteristic and the black band on the eyes explains also the Italian, English and French name, of raccoon, an equally nocturnal animal

Zoogeography

It has a very vast distribution in the Indo-Pacific. We find it from South Africa, Madagascar, East Africa and Somalia up to the Maldives, India, Sri Lanka, Thailand, Australia, Indonesia, New Guinea, Micronesia, New Caledonia, Philippines, Taiwan, and China up to southern Japan. Eastwards, it reaches the Marquesas, Ducie Island, Hawaii and the Galapagos; southwards, Lord Howe and Easter islands.

Ecology-Habitat

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It has a much varied diet that includes algae and is not based on corals © Giuseppe Mazza

It lives in the atolls and on the border of the madreporic formations up to 30 m of depth.

Morpho-physiology

The Raccoon butterflyfish can reach the 20 cm. The body is flat, more or less oval, with robust snout, slightly pointed.

The dorsal fin has 10-14 spiny rays and 20-25 soft; the anal has 3 spiny rays and 17-20 soft; the ventral ones 1 spiny ray and 5 soft; the pectoral are unarmed, with 14-17 rays, and the caudal is more or less blunt.

Yellow is the background colour. The wide carnivalesque black band hiding the eyes is followed by a white band and then by two black triangles pointing towards the back. There is also a showy black spot on the caudal peduncle, which extends like an upside down comma on the back. The higher part of the sides, dark, breaks in direction of the belly into reddish lines ending in small dots.

The caudal fin, after the translucent part, exhibits a dark orange band which is resumed by the edge of the dorsal and anal ones. It is preceded, in the yellow zone by an elegant pattern with orange small dots, like those under the operculum.

Ethology-Reproductive Biology

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It has a very vast distribution in the Indo-Pacific© Giuseppe Mazza

The Raccoon butterflyfish lives in pairs or small schools, active, as mentioned before, during the night.

It mainly nourishes of nudibranch molluscs and of tubicolous polychetes, without ignoring the crustaceans, the small benthic organisms and the algae. The polyps of madrepore enter only marginally its alimentary diet. After the fecundation, the eggs are entrusted to the currents.

The populations may double in less than 15 months, the diet is varied, and therefore the vulnerability index is low: only 16 per 100.

Synonyms

Pomacentrus lunula Lacepède, 1802; Chaetodon biocellatus Cuvier, 1831; Tetragonoptrus biocellatus Cuvier, 1831.

 

→ For general information about fishes please click here.

→ To appreciate the biodiversity within the Osteichthyes, the BONY FISH, and find other species, please click here.

 

The photographic file of Giuseppe Mazza

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