Rabbit fish

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Rabbit fish
Fox face (S. vulpinus)

Fox face ( S. vulpinus )

Systematics
Acanthomorphata
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Surgeonfish (Acanthuriformes)
Family : Siganidae
Genre : Rabbit fish
Scientific name of the  family
Siganidae
Richardson , 1837
Scientific name of the  genus
Siganus
Forsskål , 1775

Rabbit fish ( Siganus ; ( Latin = rabbit)) are a genus of marine fish that occurs in the tropical Indo-Pacific . Two species ( Signanus luridus and Signanus rivulatus ) have immigrated to the eastern Mediterranean since the Suez Canal was built . Rabbit fish eat algae and resemble the surgeon's fish (Acanthuridae) in terms of their appearance and eating habits , with which they occasionally form mixed schools. Rabbit fish live over coral reefs , seagrass meadows and algae fields. Some species also frequently go into brackish water . Rabbit fish are herbivorous and eat with mumbling movements of the upper lip (→ name).

In the tropical coastal countries they are important food fish, but can be the cause of Ciguatera poisoning .

features

Rabbit fish grow to be 8 to 18 inches long. They usually have a colorful net, point or meander-shaped drawing, which often forms a counter-shading . However, there are also brightly colored species. At night or in threatening situations, they can change their body colors significantly. Often then dark points appear. The sexes do not differ in color. In some species, the females become larger.

Unique among all bonefish families are the ventral fins, which are supported by a hard ray at the top and bottom and by three soft rays in the middle. The first hard ray of the dorsal fin points forward. The hard rays of the dorsal and anal fin are provided with poison glands at their base and can cause painful poisoning. The teeth of the rabbit fish stand in a row and are asymmetrically two-pointed. The number of vertebrae is 23.

Reproduction

Rabbit fish migrate to traditional spawning areas for reproduction. The time of reproduction is determined by the moon phase . Spawning takes place at night or early in the morning when the tide is out. Eggs and the larvae that hatch about three to five days before the new moon are pelagic . The larvae develop into a transparent, postlarval stage known as Acronurus , which still lives pelagically before the animals move on to adult life near the reef as juvenile fish. Males reach sexual maturity before females.

species

The genus is divided into two sub-genera, Siganus and Lo . The latter has an elongated snout, but otherwise does not differ from Siganus . Morphologically , all rabbit fish species are extremely similar and have e.g. B. the same fin formula. The species are therefore mainly differentiated based on their color. After death, the colors fade quickly, making it difficult to identify preserved specimens.

Compared to the 28 species listed here, FishBase lists another species with the single-spotted fox face ( Siganus unimaculatus ) (Evermann & Seale, 1907). This differs from Siganus vulpinus only by a black spot on the sides. According to observations by behavioral researcher Ellen Thaler , the fish can switch the black spot on and off depending on their mood, so it must be assumed that Siganus unimaculatus is only Siganus vulpinus with a visible side spot .

Fossil of Ruffoichthys spinosus from Monte Bolca

Fossil lore

In addition to the only recent genus Siganus , the family also includes some extinct genera that are only known from fossils and mostly come from the northern Italian fossil deposit Monte Bolca or the northern Caucasus . The extinct genera are Acanthopygaeus , Caucasiganus and Lagosiganus , as well as Eosiganus , Protosiganus , Ruffoichthys and Siganopygaeus .

literature

Individual evidence

  1. ↑ Signanus luridus in the CIESM Atlas of Exotic Fishes in the Mediterranean
  2. ↑ Signanus rivulatus in CIESM Atlas of Exotic Fishes in the Mediterranean
  3. ↑ Jonna, R. 2003. Siganidae , Animal Diversity Web.
  4. ↑ Alexandre F. Bannikov, James C. Tyler, Chiara Sorbini: Two new taxa of Eocene rabbitfishes (Perciformes, Siganidae) from the North Caucasus (Russia), with redescription of Acanthopygaeus agassizi (Eastman) from Monte Bolca (Italy) and a phylogenetic analysis of the family. Bollettino del Museo Civico di Storia Naturale di Verona, 34, 2010 Geologia Paleontologia Preistoria: 3-21
  5. ↑ James C. Tyler & Alexandre F. Bannikov (1997): Relationships of the fossil and recent Genera of Rabbitfishes (Acanthuroidei: Siganidae) . Smithsonian Contributions to Paleobiology: No. 84, pp. vi-35.

Web links

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