Test 2 Flashcards
(191 cards)
Osteichthyes timeline
earliest fossils - 420 mya(silurian) - already had distinct lineages, diversified a lot in cenozoic
Osteichthyes synapomorphies
endochondral bone, dermatocranium, teeth with roots on premaxilla maxilla and dentary, dermal bone on roof of mouth, dermal bone operculum (lost in tetrapods), branchiostegal rays (dermal bone on floor of gill cavity, lost in tetrapods), lepidotrichia, scales with enamel or ganoine, lungs
actinopterygii synapomorphy
everted brain. wtf
tribasic fin structure
fan-like. has girdle > 3 basal elements > radial pterygiophores> lepidotrichia
paleoniscoids
mid-devonian - jurassic paraphyletic extinct group, had heterocercal tail but were fish-like.
polypteriformes
bichirs, reedfish. freshwater, central african. ganoid scales, dorsal finlets, ventral paired lungs. my sweet beautiful outgroup of actinopterygians
acipenseriformes
aka chondrostei. sturgeons and paddlefish. lost most bone (some dermal left), evolved gas bladder
sturgeon facts
1-6 m, bony scutes, northern hemisphere freshwater, anadromous, bottom feeders
paddlefish
rostrum 1/3 of their body length, lots of electroreceptors. only 2 spp. planktivores in rivers, modified gill rakers
neopterygii
“new fin” a lot less basals, more lepidotrichia. includes gars, bowfins (holostei) and teleosts. also can swing out maxilla to inc buccal cavity size and improve suction
fish jaw suspension evolution
early = autodiastylic or amphistylic, now modern is methyostylic
methyostyly
hyostyly but with bone (usually can project jaw but the back joint isnt quite as flexible)
holostei
group that includes lepisosteiformes and amiiformes
lepisosteformes
gars. 7 spp, warm, temperate fresh/brackish waters. ganoid scales. physostomous swim bladder
amiiformes
bowfins. 2 spp. suction feeders. asymmetric caudal fin, physostomy
teleost synapomorphies
emerge mid-triassic. ANOTHER hox duplication (most lost 1 and have 7 copies), swim bladder is dorsal and gas exchange is lost, homocercal tail (helps with buoyancy with less use of other fins), leptoid scales (overlapping, saves weight), skull reduction, mobile maxilla and premaxilla, pelagic eggs (lost in some lineages)
pharyngeal jaws
help in place of a tongue, evolved several times in teleosts
imbricated scales
overlapping
how many teleosts
35000 spp.
elopomorpha
includes true eels, tarpon, bonefish. have leptocephalic leaf-like pelagic larvae.
leptocephalus
having a small head
catadromy
some eels - live in streams and have pelagic mating/larvae
osteoglossomorpha
250 spp. freshwater fish. most are obligate or facultative air breathers
clupeomorpha
small, silver, schooling planktivores. like 450 spp inc.herring, anchovies