Family PETROMYZONIDAE 

 Class PISCES True Fishes 



With bony jaws; with gill cover or operculum; usually with paired fins 

 Super-order GANOIDEA Ganoid Fishes 



Tail heterocercal; notochord present although restricted; cranium partly 

 cartilaginous 

 Order GLANIOSTOMI 



Mouth inferior and tube -like; several rovv-s of large bony plates on 

 sides, sometimes shed in old age; operculum not bony 

 Family ACIPENSERIDAE Sturgeons 

 Order SELACHOSTOMI 



Snout prolonged into a broad flat paddle; operculum not bony 

 Family POLYODONTIDAE Paddlefish 

 Order HOLOSTEI 



Scales rhombic; jaws elongate; vertebrae opisthocoelus 

 Family LEPISOSTEIDAE Gars 

 Order HALECOMORPHI 



Scales cycloid; with a large gular plate between the rami of the 

 lower jaw 



Family AMIIDAE Bowfin, River Dogfish 

 Super-order TELEOSTEI Bony Fishes 



Tail homocercal; notochord never complete; cranium completely ossified 

 Order ISOSPONDYLI 



No spines in fins; pelvic fins abdominal; air bladder open to gullet 

 Family HIODONTIDAE Mooneyes 

 Family CLUPEIDAE Herrings 

 Family DOROSOMIDAE Gizzard Shad 

 Family SALMONIDAE Salmon, Trout 

 Family COREGONIDAE Whitefish 

 Family THYMALLIDAE Graylings 

 Family OSMERIDAE Smelts 

 Order APODES 



Body elongate, cylindrical; no pelvic fins; no true fin spines; scales, 

 when present, minute and deeply embedded 

 Family ANGUILLIDAE True Eels 

 (Several marine families) 

 Order HETEROGNATHI 



Fins soft; with four anterior vertebrae partly fused and with Web- 

 erian ossicles; pelvic fins abdominal; brain case not extending be- 

 tween orbits 



Family CHARACINIDAE Characins 

 (Several tropical genera and species) 



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