Diversity of Fishes II

• 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

Superclass Gnathostomata• Class Placodermi †

– Bony anterior plates– Jawed with depressed flattened

bodies– Pectoral and pelvic fins

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

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

Subclass Elasmobranchii

• Predators (or scavengers)• Mainly marine habitats• Slow metabolism and slow growth• Internal fertilization• Low fecundity (few & large young)

– Ovipary– Ovovivipary– Vivipary

Oophagy orCarnivorous ovovivipary

• Subclass Elasmobranchii– Order Heterodontiformes (8 spp, bullhead and horn

sharks)• Family Heterodontidae• 2 dorsal fins each with a spine

• 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

• 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

• 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

• 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

SharksOrders

Rays & SkatesOrder Rajiformes

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).

1580-2005 Map of World's Confirmed

Unprovoked Shark Attacks (N=2,035)

Risk of Shark attack in US

SHARKSHits/Att Deaths Att Deaths

Lightning (year) 179.7* 44.9* 11.4 0.5

Alligator 365 13 503 8 Tornadoes 1036 69 213 2

Bicycles 4476 107 37 1

Animal Related Deaths - USA

Animal AverageNumber of

FatalitiesPer Year

• Deer (Vehicular Collisions) 130• Dogs 18• Snakes 15• Mountain Lions 0.6• Sharks 0.4

Equipment Year

Number of

Injuries

Nails, screws, tacks, and bolts 1996 198,849

Ladders 1996 138,894

Toilets 1996 43,687

Pruning, trimming, edging 1996 36,091

Chain saws 1996 13,458

Pliers, wire cutters, and wrenches 1996 15,957

Manual-cleaning equipment 1996 14,386

Power grinders, buffers, and polishers 1996 13,458

Buckets and pails 1996 10,907

Room deodorizers and fresheners 1996 2,599

Toilet-bowl products 1996 1,567

Paints or varnish thinners 1996 1,549

Shark injuries in U.S.A. 1996 13

Home Improvement

Florida Beaches 2000

Estimated attendance 264,156,728

Lifeguard provision of medical care

236,642

Lifeguard rescues from drowning

70,771

Drowning (lifeguard areas) 12

Drowning (non-lifeguard areas) 62

Fatalities (causes other than drowning)

58

Total fatalities 132

Unprovoked shark attack 23

Shark attack fatalities 0