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Diversity of Fishes II. Phylum Chordata –Superclass Agnatha Class Pteraspidomorphi † Class Myxini (?) Class Cephalaspidomorphi –Superclass Gnathostomata.

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Presentation on theme: "Diversity of Fishes II. Phylum Chordata –Superclass Agnatha Class Pteraspidomorphi † Class Myxini (?) Class Cephalaspidomorphi –Superclass Gnathostomata."— Presentation transcript:

1 Diversity of Fishes II

2 Phylum Chordata –Superclass Agnatha Class Pteraspidomorphi † Class Myxini (?) Class Cephalaspidomorphi –Superclass Gnathostomata Class Placodermi † Class Acanthodii † Class Chondrychthyes Class Sarcopterygii Class Actinopterygii Fish Taxa Diversity

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4 Superclass Gnathostomata Class Placodermi † –Bony anterior plates –Jawed with depressed flattened bodies –Pectoral and pelvic fins

5 Superclass Gnathostomata Class Chondrichthyes Subclass Elasmobranchii –Sharks, skates and rays –Cartilaginous skeleton, placoid scales, replacement dentition, internal fertilization and multiple gill slits. Subclass Holocephali –Chimaeras or ratfishes –Upper jaws fused to braincase, cartilaginous skeleton, single gill cover, separate anal and urogenital openings, erectable dorsal spine

6 Subclass Elasmobranchii Around 800 species of sharks and rays Cartilaginous skeleton with calcifications Teeth replaced serially Soft un-segmented fins (ceratotrichia) FIVE, six or seven external gill slits (spiracule) Buoyant livers and spiral valve intestines Internal fertilization (pelvic fin claspers) Osmotic regulation through metabolic waste products (urea and Trimethylamine oxide- TMAO) Single cloaca

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9 Subclass Elasmobranchii Predators (or scavengers) Mainly marine habitats Slow metabolism and slow growth Internal fertilization Low fecundity (few & large young) –Ovipary –Ovovivipary –Vivipary

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11 Oophagy or Carnivorous ovovivipary

12 Subclass Elasmobranchii –Order Heterodontiformes (8 spp, bullhead and horn sharks) Family Heterodontidae 2 dorsal fins each with a spine

13 Subclass Elasmobranchii –Order heterodontiformes (8 spp, bullhead and horn sharks) Family Heterodontidae 2 dorsal fins each with a spine –Order Orectolobiformes (31 spp, carpet sharks) 7 families 2 dorsal fins with no spines, short mouth Includes wobbegons, nurse sharks and whale sharks

14 Subclass Elasmobranchii –Order heterodontiformes (8 spp, bullhead and horn sharks) Family Heterodontidae 2 dorsal fins each with a spine –Order Orectolobiformes (31 spp, carpet sharks) 7 families 2 dorsal fins with no spines, short mouth Includes wobbegons, nurse sharks and whale sharks –Order Carcharhiniformes (210 spp, ground and requiem sharks) 7 families 2 dorsal fins with no spines, medium mouths Includes cat sharks, gray sharks, tiger sharks, blue sharks, hammerheads

15 Subclass Elasmobranchii (cont.) –Order Lamniformes (16 spp, mackerel sharks) 7 families 2 dorsal fins with no spines, large mouths Includes great white, mako, basking sharks, thresher sharks and megamouth –Order Hexanchiformes (5 spp, cow & frill sharks) 2 families One dorsal fin, six or seven gill slits –Order Squaliformes (74 spp, dogfish sharks) 4 families 2 dorsal fins with or without spines, no anal fin Includes dogfish and cookie-cutter sharks sharks –Order Squatiniformes (12 spp, angel sharks) 1 family Ray-like body, terminal mouth

16 Subclass Elasmobranchii (cont.) –Order Pristiophoridae (5 spp, Sawsharks) Shark-like body, flat blade snout with lateral teeth of unequal size –Order Rajiformes (456 spp, 13 families) Ventral gill openings, dorsal eyes, depressed bodies, advanced pectoral fins attached to the head Includes sawfishes, guitarfishes, electric rays, skates, stingrays, butterfly rays, eagle rays and Manta rays

17 Sharks Orders

18 Rays & Skates Order Rajiformes

19 Subclass Holocephali Chimaeras or ratfishes (58 spp.) –3 Families –Upper jaws fused to braincase, cartilaginous skeleton, single gill cover, separate anal and urogenital openings, erectable dorsal spine (poisonous) –Breath through nostrils –Male have clasper on head (internal fertilization).

20 Map of World's Confirmed Unprovoked Shark Attacks (N=2,035)

21 Risk of Shark attack in US SHARKS Hits/AttDeathsAttDeaths Lightning (year) 179.7* 44.9* Alligator Tornadoes Bicycles

22 Animal Related Deaths - USA Animal Average Number of Fatalities Per Year Deer (Vehicular Collisions) 130 Dogs 18 Snakes 15 Mountain Lions 0.6 Sharks 0.4

23 EquipmentYear Number of Injuries Nails, screws, tacks, and bolts ,849 Ladders ,894 Toilets199643,687 Pruning, trimming, edging199636,091 Chain saws199613,458 Pliers, wire cutters, and wrenches199615,957 Manual-cleaning equipment199614,386 Power grinders, buffers, and polishers199613,458 Buckets and pails199610,907 Room deodorizers and fresheners19962,599 Toilet-bowl products19961,567 Paints or varnish thinners19961,549 Shark injuries in U.S.A Home Improvement

24 Florida Beaches 2000 Year 2000 USA Beach Injuries and Fatalities *From within the jurisdictions of 68 USLA East and West Coast ocean lifeguard agencies* Estimated attendance264,156,728 Lifeguard provision of medical care 236,642 Lifeguard rescues from drowning70,771 Drowning (lifeguard areas)12 Drowning (non-lifeguard areas)62 Fatalities (causes other than drowning) 58 Total fatalities132 Unprovoked shark attack23 Shark attack fatalities0


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