Diversity of Fishes II
Fish Taxa Diversity
• Phylum Chordata
– Superclass Agnatha
• Class Pteraspidomorphi †
• Class Myxini (?)
• Class Cephalaspidomorphi
– Superclass Gnathostomata
• Class Placodermi †
• Class Acanthodii †
• Class Chondrychthyes
• Class Sarcopterygii
• Class Actinopterygii
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 oxideTMAO)
• 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 or
Carnivorous
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
Sharks
Orders
Rays & Skates
Order 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
SHARKS
Hits/Att
Deaths
Att
179.7*
44.9*
11.4 0.5
Alligator
Tornadoes
365
1036
13
69
503 8
213 2
Bicycles
4476
107
37
Lightning
(year)
Deaths
1
Animal Related Deaths - USA
Animal Average
Number of Fatalities
Per Year
•
•
•
•
•
Deer (Vehicular Collisions)
Dogs
Snakes
Mountain Lions
Sharks
130
18
15
0.6
0.4
Home Improvement
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
Florida Beaches 2000
Estimated attendance
Lifeguard provision of medical
care
Lifeguard rescues from drowning
264,156,728
236,642
70,771
Drowning (lifeguard areas)
12
Drowning (non-lifeguard areas)
62
Fatalities (causes other than
drowning)
58
Total fatalities
Unprovoked shark attack
Shark attack fatalities
132
23
0
