2. CHONDRICHTHYES
Brenna Pettersen, Brianna McClocklin, Zarria Mackey and Lyndsey Torcolacci

3. Classification Kingdom – Animalia Phylum- Chordata
Class – Chondrichthyes
Subclasses:
Elasmobranchii and holocephali

5. Distinguishing Characteristics
Cartilage skeletons
No swim bladder or lungs
Ectothermic
Internal fertilization
Gills
All carnivores
* Jaws, paired appendages, deep visceral arches next to the pharynx, an inner ear containing 3 semicircular canals, a paired nasal cavity. Well developed electroreceptors.
* Cartilaginous endoskeleton. Skin covered by placoid scales and mucous glands; Teeth are modified placoid scales.
teeth unattached to jaws,

6. Holocephali Currently 30 known species Limited to cold and salt water
Found at 200 – 2000 m
Closest living relative are sharks
Has grinding plates instead of teeth
Chimeras only surviving group
Sister order 400 million years ago

7. Elasmobranchii Sharks, skates and rays Five to seven gill pairs
Rigid dorsal fins and spines
Small placoid scales
Teeth are in series; upper jaw not fused to the cranium
Widely distributed in tropical and temperate waters

8. Rays & Skates Oldest fossil record from 150 million years ago
Camouflage on sea floor
Rays
Plate-like teeth
Bear live young (viviparous)
Stinging spine
Skates
Small teeth
Egg laying (oviparous)
Dorsal fin
No stinging spine

9. Shark Skin covered with denticles, which are small razor- sharp teeth
have very good senses
can be viviparous, oviparous or ovoviviparous
Over 400 species
Oldest species in the cartilaginous taxonomy

10. Evolution
The earliest known cartilaginous fishes were ancient sharks that were descended from bony-skeleton placoderms.
Swam in oceans 420 mya, 200 mya before the first dinosaur appeared on land.
40 million years ago the two subclasses divided

11. Fun facts Over 17% at risk with extinction
Ancient Greeks used electric rays as anaesthetic
More people are killed by vending machines than sharks
The largest ray is the Manta Ray which can have a 7 meter wing span.

12. sources http://vertebrates.voices.wooster.edu/chondrichthyes/
ftp://ftp.fao.org/docrep/fao/009/y4160e/y4160e41.pdf