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Hagfish Type
Hagfish, of the class Myxini (also known as Hyperotreti) and order Myxiniformes , are eel-shaped, slime-producing marine fish (occasionally called slime eels). They are the only known living animals that have a skull but no vertebral column, although hagfish do have rudimentary vertebrae. Along with lampreys, hagfish are jawless; the two form the sister group to jawed vertebrates, and living hagfish remain similar to hagfish from around 300 million years ago. The classification of hagfish had been controversial. The issue was whether the hagfish was a degenerate type of vertebrate-fish that through evolution had lost its vertebrae (the original scheme) and was most closely related to lampreys, or whether hagfish represent a stage that precedes the evolution of the vertebral column (the alternative scheme) as is the case with lancelets. Recent DNA evidence has supported the original scheme. The original scheme groups hagfish and lampreys together as cyclostomes (or historicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eptatretus Hexatrema
''Eptatretus hexatrema'', the sixgill hagfish or snotslang, is a species of marine fish in the hagfish family (family Myxinidae) of order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ... Myxiniformes. It is native to the South Atlantic Ocean and southwestern Indian Ocean. Distribution Southeast Atlantic: known only from Walvis Bay, Namibia to Durban, South AfricaSmith, Margaret M, and Heemstra, P. (eds.) 2003. ''Smith's sea fishes''. South African Institute for Aquatic Biodiversity, Grahamstown. Struik publishers, Cape Town, 2003. Description Maximum recorded length 80.0 cm. Depth of body 15 times total length. Six gill openings. Colour slaty grey. Egg cases ovoid about 30mm long by 12mm wide with anchor filaments at each end. Eel shaped, with six barbels on the he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
