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