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Tetrapods

5 th edition text. ~24,000 species. Tetrapods. Teleosts. lobe-fin fishes. ray-fin fishes. ray-fin fish lobe-fin fish extinct lobe-fin fish extinct early tetrapod. fin rays digits. ”early actinopterygians”. lobe-fins. ray-fins. bichirs and reedfishes freshwater (150 MYA). North

joelle-pennington
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Tetrapods

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  1. 5th edition text ~24,000 species Tetrapods Teleosts lobe-fin fishes ray-fin fishes

  2. ray-fin fish lobe-fin fish extinct lobe-fin fish extinct early tetrapod fin rays digits

  3. ”early actinopterygians” lobe-fins ray-fins

  4. bichirs and reedfishes freshwater (150 MYA) North America Eurasia Australia Africa South America cladogram for major continents

  5. Polypteriformes ~16 sp 2 genera aka ropefish similar to bichir larval stage

  6. skeleton: cartilage, bone scales: ganoid fins: “lobed”

  7. unique = independent origin

  8. gular plates lobed fins

  9. bichirs Polypterus sp. spiracles (~elasmobranchs) spiral valve intestine ventral lungs and gills

  10. Sarcopterygii Actinopterygii African Australian African bichir South American lungs gills always external larval gills

  11. reedfish Erpetoichthys calabaricus external gills as adult neoteny?

  12. “early actinopterygians” lobe-fins ray-fins

  13. gars also Central America North America Eurasia Present day ~400 MYA Australia Africa South America cladogram for major continents

  14. NEAq spotted gar Lepisosteus oculatus longnose gar Lepisosteus osseus

  15. Lepisosteiformes ~7 sp. FW bone skeleton interlocking vertebrae (~reptiles, load-bearing) extended body and snout

  16. anterior nostrils numerous teeth

  17. spiral valve intestine diamond-shaped ganoid scales (native american arrowheads)

  18. scales PLACOID GANOID ELASMOID enamel/dentine ganoine/bone enamel/bone

  19. African Australian African bichir South American lungs gills certain stages always American gar always • buoyancy • respiration external larval gills dorsal lung

  20. heart gars: up to 72 valves

  21. oviparity toxic eggs? adhesive disk larval stage

  22. distribution Great lakes to Gulf of Mexico

  23. longnose gar Lepisosteus osseus 50 lbs, 2 m spotted gar Lepisosteus oculatus 6 lbs >1 m East: introduced NEAq

  24. Atractosteus spatulaalligator gar     MCZ specimen ~3 m length

  25. ‘lie-in-wait’ or ‘ambush’ predators double-breasted cormorant with gar

  26. gar pike-characin pike or pickerel needflefish pike killifish barracuda pike-head Example: convergent evolution distant relatives converge

  27. Example: divergent evolution close relatives diverge

  28. fossils from late Paleozoic >250 MYA

  29. “early actinopterygians”

  30. Early Actinopterygii sturgeon bowfin gar

  31. sturgeon and paddlefish gars bowfin North America Eurasia Present day ~400 MYA Australia Africa South America cladogram for major continents

  32. laurentian distribution sturgeon and paddlefishes NA, Asia gars NA, CA bowfin NA

  33. Early Osteichthyes Tetrapods Teleosts lobe-fin fishes ray-fin fishes

  34. MSC Biology of Fishes at NEAq

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