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CHONDRICHTHYES Brenna Pettersen, Brianna Mc. Clocklin, Zarria Mackey and Lyndsey Torcolacci

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

Distinguishing Characteristics Cartilage skeletons No swim bladder or lungs Ectothermic Internal fertilization Gills All carnivores

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

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

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

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

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

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.

sources http: //vertebrates. voices. wooster. edu/chondrichthyes/ http: //www. seawater. no/fauna/chordata/Holocephali. html ftp: //ftp. fao. org/docrep/fao/009/y 4160 e 41. pdf http: //www 4. bluevalleyk 12. org/bvnw/jmohn/zoology/notes/phylum_chart_3. pdf http: //www. facebook. com/l. php? u=http%3 A%2 F%2 Fen. wikipedia. org%2 Fwiki%2 FChondrichthyes&h= FAQHTy. R 7 V http: //www. fish. wa. gov. au/Documents/recreational_fishing/fact_sheets/fact_sheet_rays. pdf http: //ocean. nationalgeographic. com/ocean/photos/ocean-rays/#/rays 05 -manta-raymaldives_17861_600 x 450. jpg http: //www. flmnh. ufl. edu/fish/education/questions/raybasics. html http: //www. ucl. ac. uk/museums-static/obl 4 he/vertebratediversity/chondrichthyes. html http: //www. nhc. ed. ac. uk/index. php? page=493. 470. 475 http: //palaeo. gly. bris. ac. uk/palaeofiles/fossilgroups/chondrichthyes/Characters/ synapomorphies. html