Transcript Class Chondrichthyes

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