17. Class Chondrichthyes Notes

1. Class Chondrichthyes Class Chondrichthyes
““Cartilaginous Fish”Cartilaginous Fish”
Kingdom: AnimaliaKingdom: Animalia
Phylum: ChordataPhylum: Chordata
Sub Phylum: VerterbrataSub Phylum: Verterbrata
Class: ChondrichthyesClass: Chondrichthyes

2. Class ChondrichthyesClass Chondrichthyes
Sharks, Rays, Sharks, Rays,
Skates, RatfishSkates, Ratfish
Skeleton made of Skeleton made of
cartilagecartilage

3. General CharacteristicsGeneral Characteristics
Possess movable Possess movable
jaws that usually jaws that usually
have teethhave teeth
Mouth is ventral, Mouth is ventral,
underneath the underneath the
headhead

4. General CharacteristicsGeneral Characteristics
Paired lateral finsPaired lateral fins

5. General CharacteristicsGeneral Characteristics
Rough, sand paper Rough, sand paper
like skinlike skin
Made up of scales Made up of scales
that have the same that have the same
composition as composition as
teethteeth

6. Ratfish / ChimaerasRatfish / Chimaeras
Gill slits covered by Gill slits covered by
a flap of skina flap of skin
Mostly deep-water Mostly deep-water
fishfish
Eat crustaceans and Eat crustaceans and
mollusksmollusks

7. Skates & RaysSkates & Rays
Flattened bodiesFlattened bodies
Dermersal – live on Dermersal – live on
the bottomthe bottom
Gill slits on the Gill slits on the
ventral side ventral side
(bottom)(bottom)

8. Skates & RaysSkates & Rays
Pectoral fins are flat Pectoral fins are flat
and expandedand expanded
Head fuses with Head fuses with
pectoral fins with pectoral fins with
eyes on topeyes on top

10. SawfishSawfish
Ventral gill slitsVentral gill slits
Swing blade Swing blade
through schools through schools
disabling preydisabling prey
Similar to saw Similar to saw
sharks except for sharks except for
size and gill size and gill
placementplacement

11. StingraysStingrays
Equipped with a Equipped with a
stinging spinestinging spine
Spine connected to Spine connected to
venomous glandsvenomous glands
Teeth modified into Teeth modified into
grinding platesgrinding plates

12. Manta & Devil RaysManta & Devil Rays
Not bottom Not bottom
dwellers instead dwellers instead
choose to swimchoose to swim

13. Sharks Sharks
Living FossilsLiving Fossils
Have not needed to Have not needed to
evolve for 100 evolve for 100
million yearsmillion years

14. MegalodonMegalodon
Ancient sharkAncient shark
Largest predatory fish Largest predatory fish
everever
Twice the size of a great Twice the size of a great
whitewhite

15. External StructureExternal Structure

16. Paired vs. Unpaired finsPaired vs. Unpaired fins
Paired: Pectoral & PelvicPaired: Pectoral & Pelvic
Comparable to our arms and legsComparable to our arms and legs
Unpaired: 1Unpaired: 1
stst
Dorsal, 2 Dorsal, 2
ndnd
Dorsal, Anal, Dorsal, Anal,
and Caudaland Caudal
All found along mid-lineAll found along mid-line

17. ScalesScales
Scales are very small and sharpScales are very small and sharp
Same composition as the teethSame composition as the teeth

18. JawsJaws
Made of boneMade of bone
Contain the Contain the
disposable teethdisposable teeth
In some species In some species
capable of capable of
extending jaw out extending jaw out
from bodyfrom body

19. TeethTeeth
Same composition Same composition
as the scalesas the scales
Continually shed Continually shed
and replaced by the and replaced by the
rows behindrows behind

20. RespirationRespiration
Must swim to force Must swim to force
water through their water through their
gillsgills
Some such as nurse Some such as nurse
sharks can get sharks can get
enough oxygen so enough oxygen so
they do not need to they do not need to
swimswim

21. DigestionDigestion
Very short Very short
esophogusesophogus
Stomach can be up Stomach can be up
to 1/3 the length of to 1/3 the length of
the sharkthe shark
Intestine is really Intestine is really
small, only about a small, only about a
footfoot

22. Nervous SystemNervous System
Lateral line used for sensing vibrations in Lateral line used for sensing vibrations in
the waterthe water

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

24. Nervous SystemNervous System
Paired external Paired external
nostrils that lead nostrils that lead
directly to the braindirectly to the brain
Very acute sense of Very acute sense of
smell, can detect smell, can detect
concentrations as concentrations as
low as one part per low as one part per
billionbillion

25. Shark ClassificationShark Classification
Two Super-Orders:Two Super-Orders:
–Galeomorphs & SqualomorphsGaleomorphs & Squalomorphs
Further broken down into ordersFurther broken down into orders

26. Order Heterodontiformes:Order Heterodontiformes:
Bullhead SharksBullhead Sharks
Pig like snoutPig like snout
Bottom dwellersBottom dwellers

27. Order Orectolobiformes:Order Orectolobiformes:
““Carpet Sharks”Carpet Sharks”
Very short mouthsVery short mouths
Upper lobe of Upper lobe of
caudal fin extended caudal fin extended
with reduced lower with reduced lower
lobelobe
Includes filter Includes filter
feedersfeeders

28. Order Lamniformes:Order Lamniformes:
““Mackerel Fish”Mackerel Fish”
Larger front teethLarger front teeth
Include some of Include some of
most popularmost popular
Most are active Most are active
predatorspredators
Functionally warm-Functionally warm-
bloodedblooded

29. Order Lamniformes:Order Lamniformes:
““Goblin Sharks”Goblin Sharks”
MitsukurindidaeMitsukurindidae
““Sandtiger Sharks”Sandtiger Sharks”
CarchariidaeCarchariidae

30. Order Lamniformes:Order Lamniformes:
““Ragged-Tooth Ragged-Tooth
Sharks”Sharks”
OdontaspididaeOdontaspididae
““Thresher Sharks”Thresher Sharks”
AlopiidaeAlopiidae

31. Order Lamniformes:Order Lamniformes:
““Megamouth Shark”Megamouth Shark”
MegachasmidaeMegachasmidae
““Crocodile Sharks”Crocodile Sharks”
PseudocarchariidaePseudocarchariidae

32. Order Lamniformes:Order Lamniformes:
““Basking Shark”Basking Shark”
CetorhinidaeCetorhinidae
““Mackerel Sharks”Mackerel Sharks”
LamnidaeLamnidae

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

34. Order Carcharhiniformes:Order Carcharhiniformes:
““Whaler Sharks”Whaler Sharks”
CarcharhinidaeCarcharhinidae
““Hammerhead Hammerhead
Sharks”Sharks”
SphyrnidaeSphyrnidae

35. Order Carcharhiniformes:Order Carcharhiniformes:
““Cat Sharks”Cat Sharks”
SchliorhinidaeSchliorhinidae

36. Order ChlamydoselachiOrder Chlamydoselachi
““Frilled Shark”Frilled Shark”
Eel like bodyEel like body
Teeth are three Teeth are three
prongedpronged
Deep waterDeep water

37. Order HexanchiformesOrder Hexanchiformes
““Cow Sharks”Cow Sharks”
Deep waterDeep water
Very little is knownVery little is known

38. Order EchinorhiniformesOrder Echinorhiniformes
““Bramble Sharks”Bramble Sharks”
Thick tail stalkThick tail stalk
Has bumps on skinHas bumps on skin
““hedgehog sharkhedgehog shark

39. Order SqauliformesOrder Sqauliformes
““Dogfish Sharks”Dogfish Sharks”
Large ranges of sizesLarge ranges of sizes
Generally best known sharkGenerally best known shark

40. Order SqauliformesOrder Sqauliformes
Greenland Shark Greenland Shark
(21 feet +)(21 feet +)
Dwarf LaternsharkDwarf Laternshark

41. Order SquantiniformesOrder Squantiniformes
““Angel Sharks”Angel Sharks”
Flattened bodiesFlattened bodies
Gills on ventral sideGills on ventral side
Mouth at end rather than ventral like rays and Mouth at end rather than ventral like rays and
skatesskates

42. Order PristiophoriformesOrder Pristiophoriformes
““Sawsharks’Sawsharks’
Similar to sawfish, Similar to sawfish,
but skinnier and but skinnier and
have sensitive have sensitive
barbs on snoutbarbs on snout
Alternating long Alternating long
short teethshort teeth