Class Chondrichthyes “Cartilaginous Fish” Kingdom: Animalia Phylum: Chordata Sub Phylum: Verterbrata Class: Chondrichthyes

Class Chondrichthyes Sharks, Rays, Skates, Ratfish Skeleton made of cartilage

General Characteristics Possess movable jaws that usually have teeth Mouth is ventral, underneath the head

General Characteristics Paired lateral fins

General Characteristics Rough, sand paper like skin Made up of scales that have the same composition as teeth

Ratfish / Chimaeras Gill slits covered by a flap of skin Mostly deep-water fish Eat crustaceans and mollusks

Skates & Rays Flattened bodies Dermersal – live on the bottom Gill slits on the ventral side (bottom)

Skates & Rays Pectoral fins are flat and expanded Head fuses with pectoral fins with eyes on top

Sawfish Ventral gill slits Swing blade through schools disabling prey Similar to saw sharks except for size and gill placement

Stingrays Equipped with a stinging spine Spine connected to venomous glands Teeth modified into grinding plates

Manta & Devil Rays Not bottom dwellers instead choose to swim

Sharks Living Fossils Have not needed to evolve for 100 million years

Megalodon Ancient shark Largest predatory fish ever Twice the size of a great white

External Structure

Paired vs. Unpaired fins Paired: Pectoral & Pelvic Comparable to our arms and legs Unpaired: 1st Dorsal, 2nd Dorsal, Anal, and Caudal All found along mid-line

Scales Scales are very small and sharp Same composition as the teeth

Jaws Made of bone Contain the disposable teeth In some species capable of extending jaw out from body

Teeth Same composition as the scales Continually shed and replaced by the rows behind

Respiration Must swim to force water through their gills Some such as nurse sharks can get enough oxygen so they do not need to swim

Digestion Very short esophogus Stomach can be up to 1/3 the length of the shark Intestine is really small, only about a foot

Nervous System Lateral line used for sensing vibrations in the water

Nervous System Ampullae of Lorenzini Jelly filled canals that can detect electrical fields, magnetic fields, temperature, salinity, water pressure, etc.

Nervous System Paired external nostrils that lead directly to the brain Very acute sense of smell, can detect concentrations as low as one part per billion

Shark Classification Two Super-Orders: Further broken down into orders Galeomorphs & Squalomorphs Further broken down into orders

Order Heterodontiformes: Bullhead Sharks Pig like snout Bottom dwellers

Order Orectolobiformes: “Carpet Sharks” Very short mouths Upper lobe of caudal fin extended with reduced lower lobe Includes filter feeders

Order Lamniformes: “Mackerel Fish” Larger front teeth Include some of most popular Most are active predators Functionally warm-blooded

Order Lamniformes: “Goblin Sharks” Mitsukurindidae “Sandtiger Sharks” Carchariidae

Order Lamniformes: “Ragged-Tooth Sharks” Odontaspididae “Thresher Sharks” Alopiidae

Order Lamniformes: “Megamouth Shark” Megachasmidae “Crocodile Sharks” Pseudocarchariidae

Order Lamniformes: “Basking Shark” Cetorhinidae “Mackerel Sharks” Lamnidae

Order Carcharhiniformes: “Ground or Whaler Sharks” Adaptable to many environments, even estuarine and freshwater Flappable lower eyelids

Order Carcharhiniformes: “Whaler Sharks” Carcharhinidae “Hammerhead Sharks” Sphyrnidae

Order Carcharhiniformes: “Cat Sharks” Schliorhinidae

Order Chlamydoselachi “Frilled Shark” Eel like body Teeth are three pronged Deep water

Order Hexanchiformes “Cow Sharks” Deep water Very little is known

Order Echinorhiniformes “Bramble Sharks” Thick tail stalk Has bumps on skin “hedgehog shark

Order Sqauliformes “Dogfish Sharks” Large ranges of sizes Generally best known shark

Order Sqauliformes Greenland Shark (21 feet +) Dwarf Laternshark

Order Squantiniformes “Angel Sharks” Flattened bodies Gills on ventral side Mouth at end rather than ventral like rays and skates

Order Pristiophoriformes “Sawsharks’ Similar to sawfish, but skinnier and have sensitive barbs on snout Alternating long short teeth