Whale heads

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Whale heads
Cetomimus gillii

Cetomimus gillii

Systematics
Cohort : Euteleosteomorpha
Sub-cohort : Neoteleostei
Acanthomorphata
Spinefish (Acanthopterygii)
Order : Mucous heads (Beryciformes)
Family : Whale heads
Scientific name
Cetomimidae
Goode & Bean , 1895

The whale heads (Cetomimidae; Greek ketos "whale", mimos "imitator") are a family of deep-sea fish . They are widespread in the seas of the southern hemisphere, reaching a depth of 3500 meters.

features

Whale heads stand out because of their large, deeply split mouth and are often deep red or orange in color. Light of this wavelength is already filtered out in the upper water layers, so that it appears deep black in the depths. Dorsal and anal fin located far back on the body, lack pelvic fins. The animals do not have a swim bladder . Adapted to life at great depths, the fish have only very small eyes, but a very well developed lateral line organ . Their loose, unscaled skin and the lack of luminous organs distinguish them from the other whale-head species . The largest species, Gyrinomimus grahami , reaches a length of 39 centimeters.

There is such a strong sexual dimorphism between the females and males of the whale heads that the males have been described as an independent fish family called "Megalomycteridae". Males are a maximum of 3.5 centimeters long. In addition, the larvae of the Cetomimidae deviate so much anatomically from the adult animals that a fish family of their own was established for them, the mirapinnidae . So were z. B. the males of Cetostoma regani as " Cetomimoides parri ", the larvae as " Parataeniophorus gulosus ". The connections were only recognized in 2009.

Way of life

Whale heads feed on all kinds of crustaceans. Their stomachs are extremely elastic, so that they can swallow larger prey. Since the males' sole purpose is to deliver sperm, growing larger than this is not worth it. The females, on the other hand, grow larger in order to produce as many egg cells as possible. Like many deep-sea fish, the whale heads take part in a vertical hike during the day. Every evening they hike in layers of water above 700 meters, only to disappear back into the depths at dawn. Young animals seem to prefer shallower water.

Systematics

There are 26 species in 14 genera.

Ditropichthys storeri
Gyrinomimus grahami
Mirapinna esau , post-larval juvenile stage

swell

literature

Individual evidence

  1. ↑ Daniel Lingenhöhl: Make one out of three, revealed extreme gender differences in the deep sea . Article at Wissenschaft-online.de from January 21, 2009.
  2. ↑ G. David Johnson, John R. Paxton, Tracey T. Sutton, Takashi P. Satoh, Tetsuya Sado, Mutsumi Nishida & Masaki Miya: Deep-sea mystery solved: astonishing larval transformations and extreme sexual dimorphism unite three fish families. Biol. Lett. 23 April 2009 vol. 5 no. 2 235-239 doi : 10.1098 / rsbl.2008.0722

Web links

Commons : whale heads  - collection of images, videos and audio files