The African Diving Experience

Fishwatch
 Triggerfish nr 12 - 14

First page: Titan, Orangestriped, Clown, Indian, Redtooth, Blue

Previous: Wedgetail, Boomerang, Bridle, Halfmoon, Whitetail

On this page: Gilded, Striped, Outrigger, Bluelined

12) Gilded triggerfish, Xanthichthys auromarginatus

The gilded triggerfish, Xanthichthys auromarginatus (Bennett, 1831), was not known from southern Africa, until Dennis King photographed it at Landers Reef a few years ago.  The species is sexually dichromatic; the female, is drab brown; while the male has bright yellow margins on the median fins, and the lower part of the head is bright blue.  The gilded trigger is known from depths of 8-147 m, but is rarely seen in less than 25 m; it occurs from South Africa to the islands of the central Pacific Ocean.  Attains 20 cm.

Male Gilded

Male Gilded Triggerfish

Female Gilded

Female Gilded Triggerfish

13) Striped triggerfish, Xanthicthys lineopunctatus

We collected the rare striped triggerfish, Xanthicthys lineopunctatus (Hollard, 1854), at Aliwal Shoal in a depth of 37-39 m.  Unlike some other species of Xanthichthys, the adult male and female of the striped triggerfish apparently do not differ in colour. (But perhaps our underwater photographers will prove me wrong?)  The species is also known from Mauritius, Réunion and Japan.  Attains 30 cm.

Striped

Striped triggerfish

14) Outrigger triggerfish, Xanthichthys punctatus    and    Bluelined triggerfish, Xanthichthys caeruleolineatus

The bizarre outrigger triggerfish was originally described from a 85 mm juvenile found by Mr R.T. Puffett washed up on the beach at the Van Stadens River mouth in May 1982.  This unique little triggerfish was dubbed the outrigger triggerfish for the large bony swelling below each pectoral fin, and it was described as a new species, Xanthichthys punctatus, by Margaret Smith and Phil Heemstra in 1983.  No other specimens of this new species were found until May 1994, when a moribund juvenile was picked up on the beach at Maitland by Arnold Slabbert of the Cape Nature Conservation Department.   Fortunately, Mr Slabbert gave the struggling triggerfish to Roger and Richard Matlock, who resuscitated the little fish and nurtured it for four years, by which time the bony swellings below the pectorals were much reduced, and the fish had transformed into the beautiful colours of an adult bluelined triggerfish, Xanthichthys caeruleolineatus.  Thanks to the efforts of Mr Puffett, Slabbert and the Matlocks, the benighted ichthyologists (Smith & Heemstra) who supposed that the outrigger triggerfish was a unique new species, were proved wrong.  And we now know that this bizarre little triggerfish is merely the juvenile stage of a bluelined triggerfish.  Another good example of how laymen (divers, aquarists, anglers, or anyone interested in fishes) can make a significant contribution to our knowledge of fishes.  The bluelined triggerfish occurs from South Africa to the islands of the central Pacific Ocean.   It occurs in deep water (usually 75-200 m); and, with its small mouth, it is not likely to be caught by anglers, which is why the species was not previously known from South Africa.

Adult Bluelined

Adult Bluelined Triggerfish

Outrigger

Outrigger or Juvenile Bluelined Triggerfish

Side view Outrigger

Side view of Outrigger Triggerfish

Triggerfish Index

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Text and photos Dr Phil Heemstra

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Updated on: 23/03/2001

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