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ichthyology n.
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Ichthyology

Ichthyology

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Ichthyology

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  1. Ichthyology

  2. “jawed fishes” • Class Chondrichthyes- cartilaginous • Subclass Elasmobranchii- sharks, rays, and skates • Subclass Holocephali- chimeras & ratfishes • Class Osteichthyes- bony fishes • Subclass Dipnoi- lung fishes • Subclass Crossopterygii- coelocanth • Subclass Actinopterygii- modern bony fishes

  3. Class Chondrichthyes:(Cartilaginous Fishes) • general diagnostic characters: • reduced dermal armor • cartilaginous endoskeleton & girdles • tricuspid teeth • gill slits • fins: two dorsal, no anal, stiff pectorals, flexible pelvic • heterocercal tail

  4. Sharks

  5. Sting Ray

  6. Manta Ray

  7. Chimera or Ratfish

  8. 1st Elasmobranch Radiation diagnostic characters: • shark-like appearance • terminal mouth; amphistylic jaw suspension • unique tooth replacement • claspers

  9. Claspers

  10. 2nd Elasmobranch Radiation diagnostic characters: • heterodont dentition • unique pectoral & pelvic fin arrangements • heterocercal tail

  11. Extant Forms • Elasmobranchii [sharks (360 species) , skates & rays (456 species); appear in the Jurassic

  12. diagnostic characters of sharks • hyostylic jaw suspension & rostrum • cranial kinesis- allows consumption of large food items • pectoral girdle fused ventrally • placoid scales • lack gas bladder; liver provides buoyancy (~ 25% of body mass).

  13. Hyostylic Jaw Suspension

  14. sensory systems • lateral line system (mechanoreceptors) • ampullae of Lorenzini (detects electrical impulses) • acute chemosensory • tapetum lucidum • internal fertilization and large female investment; oviparity, ovoviviparity, & viviparity

  15. Ampullae of Lorenzini

  16. Placoid Scales

  17. Placoid Scales

  18. Shark Egg Case

  19. diagnostic characters of skates & rays • hard teeth with flat crowned plates; mostly adapted for feeding on benthic invertebrates • swimming via undulations of pectoral fins • stingrays (family Dasyatidae) modified placoid scales form a sting at the base of the tail • manta rays (family Mobulidae) plankton feeders

  20. Cartilaginous Skeleton

  21. Shark Anatomy Link Click Here

  22. Class Osteichthyes: “bony fishes” • most abundant and diverse vertebrates >21,000 species • bony scales (enlarged in the head region) • operculum covering the gills • stream-lined; laterally compressed • ossified endoskeleton; secondarily lost in some species

  23. Operculum

  24. Dipnoans • subclass Dipnoi- "double breathers"; lungfishes • upper jaw fused to the brain case; large, crushing tooth plates • two dorsal fins • paired fins

  25. Crossopterygians • dominant fresh water predators during the Devonian period • rhipidistians (ancestor to amphibians) & coelacanth; Latimeria (extant)

  26. important structural characteristics: • lobed fins with elements connecting to pectoral & pelvic girdles • autostylic jaw suspension- jointed braincase (jaw connects directly to the brain case) • labyrinth tooth- complex folding of the enamel

  27. Coelocanth (Latimeria)

  28. Actinopterygians (ray-finned fishes) • most modern bony fishes; subclass Actinopterygii • important structural characteristics: • ganoid scales • distinctive pectoral & pelvic girdles • fins attach to the body via flexible fin rays instead of a fleshy lobe • branchiostegal rays • no internal nares

  29. Branchiostegal Rays

  30. Ganoid Scales

  31. Ctenoid Scales Cycloid Scales

  32. “bony fish”

  33. Paddlefish (Polydon)

  34. Sturgeon

  35. Fish Diversity

  36. Smallmouth Bass

  37. Green Sunfish

  38. Catfish

  39. Oklahoma Non-game Fish