Class ChondrichthyesClass Chondrichthyes

aka Cartilaginous fishesaka Cartilaginous fishes

sharks and rayssharks and rays

General CharacteristicsGeneral Characteristics

These organisms have a skeleton made of These organisms have a skeleton made of cartilagecartilageThese organisms have movable jaws with lots of These organisms have movable jaws with lots of teeth teeth Mouth is almost always located under the headMouth is almost always located under the head

These organisms have paired lateral finsThese organisms have paired lateral finsSkin is covered in placoid scalesSkin is covered in placoid scales Sand paper like material that are made of the same Sand paper like material that are made of the same

material as the teethmaterial as the teeth

Placoid Scales

SharksSharks

Adapted for fast swimming and some are the top Adapted for fast swimming and some are the top predators in the seapredators in the seaVery few have evolved from their original formsVery few have evolved from their original formsThey have a well developed caudal finThey have a well developed caudal finTypically have paired dorsal and pectoral finsTypically have paired dorsal and pectoral finsThey have 5 to 7 gill slits on each side of the They have 5 to 7 gill slits on each side of the bodybodyOften have rows of powerful teeth and Often have rows of powerful teeth and constantly replace teeth as they lose themconstantly replace teeth as they lose them

Sharks cont.Sharks cont.

Found mostly in tropical waters at almost all Found mostly in tropical waters at almost all depthsdepthsFished for their meat, oil and skin which is used Fished for their meat, oil and skin which is used like leatherlike leatherShark fins are used in the Orient for medicinal Shark fins are used in the Orient for medicinal soupssoupsOver fishing of sharks has damaged the Over fishing of sharks has damaged the populations so restrictions are beginning to populations so restrictions are beginning to apply apply

Sharks cont.Sharks cont.

Hammerhead SharkHammerhead Shark Flattened headsFlattened heads Eyes and nostrils at Eyes and nostrils at

the tips of the flat headthe tips of the flat head Head is used as a Head is used as a

rudderrudder Space between eyes Space between eyes

and nostrils improves and nostrils improves sensory abilitiessensory abilities

Sharks cont.Sharks cont.

Whale SharkWhale Shark Largest fishLargest fish Found in tropical Found in tropical

waterswaters Can be 60 ft longCan be 60 ft long All are filter feedersAll are filter feeders

Rays and SkatesRays and Skates

Almost all have flattened bodies and are Almost all have flattened bodies and are bottom dwellersbottom dwellers

The most identifiable characteristic are the The most identifiable characteristic are the ventrally located gill slitsventrally located gill slits

The pectoral fins are greatly expanded The pectoral fins are greatly expanded and resemble wingsand resemble wings

StingrayStingray

Most common type of ray off Most common type of ray off our beachesour beachesHave a whip like tail with a Have a whip like tail with a barb at the basebarb at the baseThe barb has a poison gland The barb has a poison gland Often cover themselves with Often cover themselves with sandsandFeed on clams, crabs and Feed on clams, crabs and other small fishesother small fishesTeeth are modified into Teeth are modified into grinding plates to crush their grinding plates to crush their preyprey

Electric RayElectric Ray

Have specialized cells Have specialized cells on each side of the on each side of the body that produce body that produce electricityelectricity

Stun fish to eatStun fish to eat

Ancient peoples used Ancient peoples used to use the shock to to use the shock to cure illnessescure illnesses

Rat FishRat Fish

Have only one Have only one pair of gill slitspair of gill slits

Some have a Some have a long rat-like taillong rat-like tail

Feed on Feed on crustaceans crustaceans and mollusksand mollusks