Lesson 8 -- Sarcopterygii (lobe finned fishes) Flashcards
1
Q
tetropodomorph
A
- almost perfect fossil found in quebec –> doesnt mean that that was there the aninal lived –> land was constantly moving
2
Q
coelacanthiformes
A
- long hisotry
- deep into the devonian
- come to an abrupt hault 66 million years ago
- knew that colecanths were hugely represented in the fossil record
– all come to an end –> no colecanths from rocks that were younger than that
– paleoenthiligical scientist on holiday – finds a freshly killed colecanth - these things persist but they are just very good at hinding
- 2nd species discovered on coast of indonesia
3
Q
characteristics of coleacanth
A
- have a unique electroreceptive system
-paired fins - anal and second dorsal fin
- osmolality of their blood is very close to sea water –> kind of like chondrithyea
- give live births to adult looking pups
- don’t know how they accomplish internal fertilization because there is no “penis”
- do not do well in captivity
- have an intrarcranial joint
^^^^ only extant vertebrate with this kind of joint
4
Q
ceolocants
A
- some quite enormous fihses
- move their fins in diagonal oaurs
5
Q
lungfish
A
freshwater fish that belong to dipnoan
6
Q
dipnoans
A
- lack an articulated and toothbearing premaxillary and mandible
- all extant are freshwater
- skeletons are mostly cartilagenous
— but hightly mineralized
— pedomorphic traits
— all have this fused dorsal/caudal/anal fin
^^^ as the embryo develops, they reatin this lack of separation among fins
7
Q
pedomorphic traits
A
——-traits retained into adulthood that have a juvenile like trait
in HUMANS –> babies have large heads and so do adults
8
Q
austrailian lungfush
A
- almost uses its gills entirely for ventilation
- no parental care after spawning
- intense male courtship
9
Q
south american lungfish
A
- an obligate air breather
- has to use its lungs to survive
- comes to the surface and gulps down air to survive
10
Q
African lungfish
A
- uses lungs to take on oxygen
- but uses gills to filter out CO2
- in seasonal times where their water disappears
— they bury into the mud and lower their metabolic rate
— period of dormacy
— come out after the rains come
— behavior is known to be quite ancient
11
Q
tetropodomorph
A
- derived tetrapod fishes have most of the derived skeleton that we have today
- shows how close we are to these other forms of sarcopteriggi
12
Q
tikaalik
A
- from the late denovian
- “fishopod”
- number of traits you would find in both fish like and tetrapod like
13
Q
tetrapods (Ichthyostega)
A
- ear region for underwater hearing
- paddle like hindlimbs – suggest aquatic
- forelimbs didn’t evolve (or somehow was cut off)
14
Q
denovian tetrapod
A
presence of zigapophysis –> make vertebral column much more resistant for torsion – -good for resistance to gravity
15
Q
not quite a denovian tetrapod
A
pelvic fin
