Marine Vertebrates

Types of Fishes

I) Vertebrates

A) Subphylum Vertebrae

B) Four characteristics of chordates

C) Backbone: AKA Spine or Vertebral Column1) 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 ventral1) Underneath the head

E) Paired lateral fins

F) Sandpaper-like skin because of Placoid Scales

III) Cartilaginous Fishes

G) Sharks1) ~350 living species2) Caudal Fin is

Heterocercala) Upper lobe longer than

lower lobe

3) Fusiform, or spindle-shaped bodies

4) Five to seven gill slits5) Powerful jaws with rows

of teetha) Continuously replaced

6) Carnivores & Filter Feeders

http://www.boattalk.com/sharks/greatwhite.htm

III) Cartilaginous Fishes

H) Rays & Skates1) ~450-500 known species2) Dorsoventrally flattened3) Demersal: fish that live

on the bottom4) Five ventral gill slits5) Stingrays

a) Whip-like tail with stinging spines

6) Electric Raysa) Electric organs on each

side of head

7) Skates lack the stinging tail

III) Cartilaginous Fishes

I) Ratfish: AKA Chimaeras1) ~30 known species

2) Only one pair of gill slits covered by a flap of skin

3) Long, rat-like tail

IV) Bony Fishes

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