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FISH_TAXONOMY_from_reader_10.09 - FISH TAXONOMY Subphylum...

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FISH TAXONOMY Subphylum: Craniata Superclass: Agnatha” Jawless Fishes Identifying Characteristics (I.C.): Agnathans are eel-like fishes which lack paired fins, jaws, and scales . They have pore-like gill openings . Class: Myxini Order: Myxiniformes Family: Myxinidae Hagfishes I.C.: Eel-like fishes with a sucking funnel shaped mouth surrounded by barbels . Myxinids typically have 1 or 5-16 porelike gill openings . Mouth has horny plates with rows of sharp teeth . Two rows of teeth are located on the tongue. The eyes are often rudimentary, essentially blind . Single median nostril in front of head. There is no larval stage. Distribution : Myxinids are exclusively marine between 100 and 3500 ft . They are most often found on mud bottoms. There are 25 species in the family and order. Ecology : Myxinids are scavengers on fish. They are most often encountered in connection with fish trap or long line fisheries where they may cause considerable damage to the catch. Repulsive little creatures, Myxinids burrow into dead, dying, or confined fish through the mouth or anus and proceed to eat their prey from the inside out . All species are oviparous, laying sausage-shaped egg cases. Eptatretus stoutii Pacific Hagfish I.C.: In addition to the typical Agnathan characters, E. stoutii is easily identified by its lack of visible eyes, 10 - 14 gill pores, and a flat snout with eight barbels. Dist.: Southern Alaska to Baja Eco.: Typical of the family. Infraphylum: Vertebrata Superclass: “ Agnatha” Class: Petromyzontida Order: Petromyzoniformes Family: Petromyzontidae
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Lampreys I.C. : Petromyzontids are cylindrical eel-like fishes with a sucking mouth armed with a circle of horny teeth . All species have 7 pairs of gill pores . Lampreys possess moderately developed eyes but lack barbels . Single nostril on top of head. In most species a dorsal fin fold is separated from the caudal fin . Dist. : The family Petromyzontidae (~40 species) is confined to the Northern Hemisphere. Four species in two families are found in the Southern Hemisphere. Most lampreys are found in freshwater , but a few species are anadromous (spawn in freshwater, but spend their adult lives in the ocean). Eco. : Petromyzontid eggs hatch into a special larval form, the ammocoetes. The ammocoetes spend several years in the fine mud and sand of freshwater streams. They feed by capturing small organisms on mucus secreted by the gills and pharynx. After metamorphosis to the adult form, they may either forego further feeding and immediately begin breeding or may assume a new parasitic feeding pattern. Most lamprey species are parasitic . Parasitic species use their suctorial lips to attach themselves to other fishes. Aided by an anticoagulant in their saliva, lampreys employ numerous, tiny teeth to rasp into the flesh of their hosts and thereby drain fluids and loose tissues. The impact of lampreys on Pacific fish species is not well known; however, combined with overfishing, the sea lamprey, Petromyzon marinus , devastated commercial stocks of lake trout and ciscoes in the Great Lakes.
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FISH_TAXONOMY_from_reader_10.09 - FISH TAXONOMY Subphylum...

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