Osteichthyans (Bony Fish)

Extinct: Placoderms, Ostracoderms, Acanthodians
Sarcopterygii (lobe finned fish)
1. Fins: Extended central shaft bone - feather/leaf like
2. Early forms: long & cylindrical
3. Ancestors to tetrapods
4. 2 dorsal fins + epichordal tail lobe. Fleshy paired fins, bony axis
5. Dipnoi: Lungfish
  1. 6 spp - freshwater only
  2. Autostylic Jaw
    1. Lack teeth (premax & maxillary)
      1. Toothy palate
    2. Durophagous - eat shelled stuff
  3. Caudal, anal and dorsal fins fused
  4. Aesteviation (torpor when dry)
    1. Slime cocoon in dry season
6. Actinistians: Coleocanths
  1. Fin rays from lobes - 3 lobed tail
  2. Rostral organ - electroreception?
  3. 2 extant spp - marine
  4. Fat filled swim bladder with ossified walls
    1. Tapetum lucidum 250-300m depth
  5. Ovoviviparous - 9cm eggs. 13 month gestation 40cm pups
Actinopterygii (ray finned fish)
1. Fins: Bones at base - fanlike
  1. Paired, long fin base
2. Mid Devonian fossils - small 5cm
3. (early specimens) Heterocercal tails
4. Scales interlock - Ganoine
5. Non solid cheek - increase orobranchial chamber, increase jaw muscles
6. Chondrosteans
  1. Polypteryformes
    1. 11 spp - birchirs/reedfish
    2. heterocercal tails, fleshy fin base. flag like dorsal finlets
    3. Well ossified skeleton. Ganoid scales
  2. Acipenseriformes
    1. ~30spp - sturgeons/paddlefish
    2. Sturgeons (Acipenseridae)
      1. Lack endochondral bone (decreased dermal bone)
      2. Heterocercal tails
      3. Protrusible Jaws (suction)
        5 rows enlarged scale
      4. N. Hemisphere only, FW & Marine. Only breed in FW
    3. Paddlefish (Polyodontidae)
      1. 2 extant spp. Up to 2m long
      2. Largely decreased dermal ossification
      3. Large rostrum & ampullary organs
      4. Filter feeders
  3. Neopterygians
    1. Lepisosteiformes (Gars 7sp)
      1. Piscivorous
      2. 1-4m inhabit FW & estuaries
        Warm temperate regions
      3. interlocking multilayered scales
    2. Amiiformes (Bowfin 1sp)
      1. Single layered scales
      2. Jaw modified - suction
        Eat anything
      3. Asymmetrical caudal fin
    3. Teleosteans (all other fish 27000sp) 4 Clades:
      1. Osteoglossomorpha (~220sp)
        Jurassic seas: tropical FW
        Jaw mechanics - bony mouths
      2. Elomorpha (~800sp eels)
        Late jurassic
        Marine
        Leptocephalus larvae
        Transparent eel larvae - grow large
      3. Clupeomorpha (~360-400sp)
        Plankton eaters
        Mouth and gill straining apparatus
        Highly valuable
      4. Euteleostei (the rest)
        Mid - late cretaceous
        Weberian apparatus (connects swim bladder to auditory system)

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Osteichthyans (Bony Fish)

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	Creado por Litty Carter hace más de 11 años