sharks
Post on 06-Jan-2016
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Sharks
Class Chondrichthyes
• skeletons made up entirely of cartilage
• cartilage contains thousands of minute prisms containing mineral that strengthens bones (hydroxyapatite)
• distinctive teeth, highly resistant to decay
Order Carcharhiniformes
• “Ground Sharks”
• nictitating eyelids present
• mouth behind front of eyes
• five pairs of gill slits
• anal fin present
Family Carcharhinidae• head “normal”
without lateral expansions
• first dorsal fin originates in front of pelvic fins
• anal fin trailing margin strongly concave
Tiger Shark (Galeocerdo cuvier)
• snout very short, bluntly squared-off
• upper lobe of caudal fin very long, sharply pointed
• pigmentation pattern: dark spots/vertical bars on back and flanks
Tiger Shark (Galeocerdo cuvier)
• electromagnetic receptors, Ampullae of Lorenzini
• lateral line reads vibrations in water, movement of animals nearby
• 2nd most attacks on humans, behind great white
Family Sphyrnidae
• head with lateral, canard-like extensions
• pelvic fins triangular
Scalloped Hammerhead (Sphyrna lewini)
• head,hammer-narrow and broadly arched with prominent indentations at each nare and the midline
• pelvic fins triangular
• first dorsal fin origin over or slightly behind pectoral axil
Scalloped Hammerhead (Sphyrna lewini)
• tends to form huge schools
• hammer enhances senses of smell, electroreception, lift and maneuverability
• prevents 3D vision and jaw protrusion
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