Whole fish head subclass subclass holocephali large head and side flat, thin tail, four pairs of gill slits on both sides, outside a film-like gill cover, only one pair of gill openings whole body, the body smooth and without scales, lateral line developed. A slender tail whip, crooked-type tail. This subclass each other due to the healing of the upper jaw and skull, named after the first full class, is an original, one of the few deep-sea fish population. No cloaca, cloaca and anus were opening in the body, except the male has a pair of fins, there are one pair of ventral fins front (ventral mating device) and an amount of fins (head mating device). The members of this small class groups, based on porbeagle, chimaeras, strange ghost sharks and shark's name famous, at least 300 million years ago (Carboniferous or Devonian) on sub-category from the board out of a deformed gill residual expenses. The first fossil was found chimaeras in the Jurassic, Cretaceous and early Triassic (120 to 50 million years ago) has been declining since then peaked.
Today the total number of surviving about 25 species. Anatomically, they have sharks and bony fish like a strange hybrid feature. Jaw tooth plate instead of the big mouth teeth. Upper jaw and skull which is completely healed rarest fish growth. Their diet includes algae, molluscs, echinoderms, crustaceans and fish - in general, such a special grinding teeth for eating mixed foods. Silver fish shark is not a commodity, so are rarely caught. Their shapes strange and beautiful, pearl-like iridescent body and bright emerald-colored eyes only see that convincing. |
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