1. Class Chondrichthyes Kingdom: Animalia Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Subclass: Holocephali
Subclass: Elasmobranchii
Superorder Batoidea
Superorder Selachimorpha

2. Cartilaginous Fish Includes: Sharks Rays Skates
Ratfish/Chimeras/Ghost fish

3. General Characteristics:
Jawed fish
Skeleton made of cartilage
Lack swim bladder
Teeth & vertebrae sometimes calcified

4. General Characteristics:
Possess movable jaws
Mouth is ventral, underneath the head
Countershading – the ventral sides are light colored while the dorsal sides are darker creating a simple camouflage

5. Evolution: Earliest relatives found in the Devonian Age
Modern looking sharks first appear in the Jurassic Era

6. Evolution Megalodon Ancient Shark Largest predatory fish ever
Twice the size of a Great White

7. Subclass Holocephali Includes: Ratfish/Chimeras Deep water fish
Large head & eyes
Gill slits covered by a flap of skin
No scales, skin instead
Caudal fin developed into “rat-like” tail
Eats crustaceans & mollusks

8. Subclass Elasmobranchii
Includes: Sharks, Rays, & Skates
Denticles – streamlined scales made of the same material as their teeth

9. Energy Efficiency:
Cartilage skeleton make them lighter, thus takes less energy to remain buoyant
Buoyant oils in liver
Fins at angles to provide lift
Skin elasticity transfers energy to tail
Scales reduce friction (smooth towards tail, rough towards head)
Store urea to maintain similar density to water

10. Superorder Batoidea Includes: Skates, Rays, & Sawfish Flattened body
Demersal – live on the ocean floor
Gill slits on ventral (bottom) side

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

12. Skates vs. Rays

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

14. Manta & Devil Rays
Not bottom dwellers instead choose to swim

15. Sawfish vs. Sawshark
Sawfish categorized with the rays while sawshark categorized with the sharks
Sawfish have ventral gill slits, smaller and flatter body
Sawshark have gill slits on the side, rounded body, bigger overall, and presence of barbels

16. Superorder Selachimorpha
Includes: Sharks
Gill slits on the side
Paired & unpaired fins
Most are quite mobile and designed for fast swimming

17. 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

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

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

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

21. 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 (pumping mechanism)
Sharks that do not have this mechanism go through active periods and rest periods where they lower body functions

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

23. Nervous System
Lateral line used for sensing vibrations in the water

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

25. 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

26. Shark Classification Two Sub-Orders: Further broken down into orders
Galeomorphs & Squalomorphs
Further broken down into orders

27. Order Heterodontiformes:
Bullhead Sharks
Pig like snout
Bottom dwellers

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

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

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

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

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

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

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

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

36. Order Carcharhiniformes:
“Cat Sharks”
Schliorhinidae

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

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

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

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

41. Order Sqauliformes
Greenland Shark (21 feet +)
Dwarf Laternshark

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

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