General Vertebrate Zoology Exam 1

Front 1

History of Chondrichthyes

Back 1

-Early Devonian
-Three major radiations
-Prismatic endoskeletal calcification
-Holocephalii
-Neoselachii- larger number, multiple gill openings

Front 2

Characteristics of the Paleozoic Radiation

Back 2

-Three-cusped teeth
-Cladoselache
-Amphistylic jaw suspension- palatoquadrate bone is hooked inseveral places along bottom of cranium, some motion not as much as modern sharsk
-Tooth whorls
-Broad-based fins
-Caudal fins with lateral keels
-Few placoid scales- simple, composed of dentine cusp, very few inthis particular radiation
Pelvic claspers- internal fertilization, ancestral or derived? Not found in all of them

Front 3

Characteristics of the Early Mesozoic Radiation of Chonrichthyes

Back 3

-Heterodont dentition
-Hybodus
-Narrow-based fins
-Ceratotrichia- protenatious substance infins for more flexibility
-Anal fin and heterocercal tail
-Hemal arches- protect arteries and veins below notochord, ribs appear
-Internal fertilization- pelvic claspers in males now the norm elaborate courtships

Front 4

Characteristics of the Modern Radiation of Chondrichthyes

Back 4

-Triassic, Jurassic
-Mouth ventral- instead of terminal
-Calcified Vertebrae
-Tooth material more complex- enamel like material

Front 5

Characteristics of the Neoselachii Sharks

Back 5

-“New Sharks”
-Squaloid sharks- more primitive
-Galeoid sharks- tiger sharks, white sharks
-Multiple gill openings on sides of head = pleurotremate
-Cartilagenous vertebral centra- notochord remnants
-Intercalacy plates
-Placoid scales- dermal cells are clustered and fused into larger plates, Shagreen- body covering that if flexible and protective, Modern sharks add more and replace scales

Front 6

How does a Shark hunt?

Back 6

-Chemosensation- use first, pick up odor, very sensitive odor, swims up cradient
-Ampullae of Lorenzini- when they get closer these come into play (and lateral line/inner ear)
-Lateral line and inner ear-
-Vision- when really close to stimulus
-Heavy on rod structure- in retina
-Tampetum Lucidum- low light, have a dimmer in the high light
-Nictitating membrane- pull up over eye to protect eye during an attack

Front 7

Characteristics of Shark feeding

Back 7

-Anatomy
-Hyostylic jaw suspension
-Cranial kinesis- opens 90 degrees, and cranial portion of head moves laterally to increase oral brachial opening
-Modes of feeding
-Filter-feeding- whale sharks, cough after feeding
-Exsanguination- bleeding to death
-Heterodont teeth

Front 8

Characteristics of Shark Reproduction

Back 8

-Internal fertilization- males have claspers
-Quantity vs. Quality- bony cody 2-11 million egg, sharks 20-30 pups have high parental investment
-Lecithotrophy- makes a yolk to nourish an embryo, eggs produced proteinatious case, live solely on the yolk
-Matrotrophy- the female herself carry the young in her reproductive tract
-Siblicide in utero- fraternitize, siblings eating potential siblings, few young born that are mini replicas of adults
-Placentotrophic matrotrophy- young feed on blood stream of female
Sharks do aggregate for reproduction

Front 9

Shark Conservation

Back 9

-Loss of nursery grounds- limited space for little sharks to grow bigger
-Overexplitation
-Shark finning
-Slow growth = SLOW recovery!!

Front 10

Characteristics of Skates and Rays

Back 10

- skates have two dorsal fins and caudal fin on tail
-Hypotremates “below opening”
-Durophagous feeding habits
-Dorsoventrally flattened body forms
-Venomous barbs or spines- venom contains enzymes, serotonin severely contract muscles

Rays produce electrical signals from tail or modified gill structures, can recognize other conspecifics, skates lay eggs, rays bear live young
Sexually dimporphic in rays, male teeth grow sharp teeth for reproducing

Front 11

Characteristics of Holocephalii

Back 11

whole head doesn’t appear to segment body, 33 documented species, move by lateral undulations
-Ratfishes
-Mostly deep water
-Elaborate rostral extensions
-Tooth plates- eat shrimp, crustaceans, mollusks
-Armaments- poison gland