17. Class Chondrichthyes Notes
- 1. Class Chondrichthyes “ Cartilaginous Fish” Kingdom: Animalia Phylum: Chordata Sub Phylum: Verterbrata Class: Chondrichthyes
- 2. Class Chondrichthyes Sharks, Rays, Skates, Ratfish Skeleton made of cartilage
- 3. General Characteristics Possess movable jaws that usually have teeth Mouth is ventral, underneath the head
- 4. General Characteristics Paired lateral fins
- 5. General Characteristics Rough, sand paper like skin Made up of scales that have the same composition as teeth
- 6. Ratfish / Chimaeras Gill slits covered by a flap of skin Mostly deep-water fish Eat crustaceans and mollusks
- 7. Skates & Rays Flattened bodies Dermersal – live on the bottom Gill slits on the ventral side (bottom)
- 8. Skates & Rays Pectoral fins are flat and expanded Head fuses with pectoral fins with eyes on top
- 10. Sawfish Ventral gill slits Swing blade through schools disabling prey Similar to saw sharks except for size and gill placement
- 11. Stingrays Equipped with a stinging spine Spine connected to venomous glands Teeth modified into grinding plates
- 12. Manta & Devil Rays Not bottom dwellers instead choose to swim
- 13. Sharks Living Fossils Have not needed to evolve for 100 million years
- 14. Megalodon Ancient shark Largest predatory fish ever Twice the size of a great white
- 16. Paired vs. Unpaired fins Paired: Pectoral & Pelvic Comparable to our arms and legs Unpaired: 1 st Dorsal, 2 nd Dorsal, Anal, and Caudal All found along mid-line
- 17. Scales Scales are very small and sharp Same composition as the teeth
- 18. Jaws Made of bone Contain the disposable teeth In some species capable of extending jaw out from body
- 19. Teeth Same composition as the scales Continually shed and replaced by the rows behind
- 20. 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
- 21. Digestion Very short esophogus Stomach can be up to 1/3 the length of the shark Intestine is really small, only about a foot
- 22. Nervous System Lateral line used for sensing vibrations in the water
- 23. Nervous System Ampullae of Lorenzini Jelly filled canals that can detect electrical fields, magnetic fields, temperature, salinity, water pressure, etc.
- 24. 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
- 25. Shark Classification Two Super-Orders: Galeomorphs & Squalomorphs Further broken down into orders
- 26. Order Heterodontiformes: Bullhead Sharks Pig like snout Bottom dwellers
- 27. Order Orectolobiformes: “ Carpet Sharks” Very short mouths Upper lobe of caudal fin extended with reduced lower lobe Includes filter feeders
- 28. Order Lamniformes: “ Mackerel Fish” Larger front teeth Include some of most popular Most are active predators Functionally warm-blooded
- 29. Order Lamniformes: “ Goblin Sharks” Mitsukurindidae “ Sandtiger Sharks” Carchariidae
- 30. Order Lamniformes: “ Ragged-Tooth Sharks” Odontaspididae “ Thresher Sharks” Alopiidae
- 31. Order Lamniformes: “ Megamouth Shark” Megachasmidae “ Crocodile Sharks” Pseudocarchariidae
- 32. Order Lamniformes: “ Basking Shark” Cetorhinidae “ Mackerel Sharks” Lamnidae
- 33. Order Carcharhiniformes: “ Ground or Whaler Sharks” Adaptable to many environments, even estuarine and freshwater Flappable lower eyelids
- 34. Order Carcharhiniformes: “ Whaler Sharks” Carcharhinidae “ Hammerhead Sharks” Sphyrnidae
- 35. Order Carcharhiniformes: “ Cat Sharks” Schliorhinidae
- 36. Order Chlamydoselachi “ Frilled Shark” Eel like body Teeth are three pronged Deep water
- 37. Order Hexanchiformes “ Cow Sharks” Deep water Very little is known
- 38. Order Echinorhiniformes “ Bramble Sharks” Thick tail stalk Has bumps on skin “ hedgehog shark
- 39. Order Sqauliformes “ Dogfish Sharks” Large ranges of sizes Generally best known shark
- 40. Order Sqauliformes Greenland Shark (21 feet +) Dwarf Laternshark
- 41. Order Squantiniformes “ Angel Sharks” Flattened bodies Gills on ventral side Mouth at end rather than ventral like rays and skates
- 42. Order Pristiophoriformes “ Sawsharks’ Similar to sawfish, but skinnier and have sensitive barbs on snout Alternating long short teeth