Marine Vertebrates Types of Fishes

I) Vertebrates A)Subphylum Vertebrae B)Four characteristics of chordates C)Backbone: AKA Spine or Vertebral Column 1)Dorsal row of hollow bones 2)Protects the Nerve or Spinal Cord

II) Jawless Fishes A)Class Agnatha B)Around 30 known species C)Includes hagfish & lampreys D)Feed by suction with aid from teeth E)No fins, & lack true vertebrae

III) Cartilaginous Fishes A)Class Condrichthyes B)Skeleton made of cartilage C)Movable jaws D)Mouth ventral 1)Underneath the head E)Paired lateral fins F)Sandpaper-like skin because of Placoid Scales

III) Cartilaginous Fishes G)Sharks 1)~350 living species 2)Caudal Fin is Heterocercal a)Upper lobe longer than lower lobe 3)Fusiform, or spindle- shaped bodies 4)Five to seven gill slits 5)Powerful jaws with rows of teeth a)Continuously replaced 6)Carnivores & Filter Feeders

III) Cartilaginous Fishes H)Rays & Skates 1)~ known species 2)Dorsoventrally flattened 3)Demersal: fish that live on the bottom 4)Five ventral gill slits 5)Stingrays a)Whip-like tail with stinging spines 6)Electric Rays a)Electric organs on each side of head 7)Skates lack the stinging tail

III) Cartilaginous Fishes I)Ratfish: AKA Chimaeras 1)~30 known species 2)Only one pair of gill slits covered by a flap of skin 3)Long, rat-like tail

IV) Bony Fishes

A)Class Osteichthyes B)~23,000 known species C)Skeleton made of bone D)Cycloid or Ctenoid Scales E)Operculum: Gill Cover F)Upper & lower tail fin same size: Homocercal

Operculum

Homocercal

IV) Bony Fishes G)Fin Rays: thin membranes supported by bony spine H)Anterior, terminal mouth I)More flexible jaws with teeth attached to jawbone J)Swim Bladder: gas- filled sac above stomach & intestines that helps in buoyancy