Osteichthyes - >27,000 bony fishes, 13,000 herps, 9000 birds, 4800 mammals
Bony Fish Characteristics–
Endochondral bone
Bony operculum
Covering gills
Extinct Antecedents
Placoderms (Arthrodires)
Neck Joint
Two major branches
Of Osteichthyes
1. Sarcopterygia
Lung fish Fig 6-3
Coelocanths Fig 6-4
Tetrapods
2 Actinopterygia
Ray-finned fishes
Trends in Actinopterygian Evolution Fig 6-2, 6-8
1) Heavy body armor
Ganoid scales
light overlapping scales
cycloid, ctenoid
Ctenoid
2) Heterocercal
Heterocercal tail of Paddlefish
Homocercal tail
Homocercal tail of swordfish
Gar
Bowfin (Amia)
3) Development of gas/swim bladder for buoyancy Fig 4-3
Physostomous
Physoclistous
Ovale
1. Are mammals on this cladogram? If so where?
2. What is the major difference between ostracoderms and placoderms?
3. For actinopterygians, what is the ancestral condition in terms of scale type
and tail type?
4. Sharks maintain neutral buoyancy without a swim bladder. How?
5. What would you predict about the organs for maintaining neutral
buoyancy in bottom-dwelling rays and actinopterygians?
6. If a physoclistous fish were swimming to deeper depths, what would the
ovale of the swim bladder be doing?
4) Evolution of protrusible jaws and pharyngeal jaws
Fig 6-7
Fig 6-7
4) Evolution of protrusible jaws and pharyngeal jaws
Scissors =
gar
Maxilla rotates out – trout
Premaxilla slides out
Protrusible tube
Advantage??
Sling-jaw Wrasse – Now that’s protrusible!
Pharyngeal Jaws
Advantage??
Reproduction – most actinopterygians oviparous
Marine- planktonic
Freshwater & nest–guarding Marine
- demersal
Planktonic larvae
of marine fish
Note adaptations
to blend in with plankton
Or to avoid predation
Fig 6-15
Swimming and Actinopterygian fish
“The gap between the swimming fish and the scientist is closing,
but the fish is still well ahead”
Lindsey 1978
Swimming styles and swimming efficiency Fig 6-14, 6-15, 6-16
Anguilliform
Carangiform
Ostraciform
Fig 6-13
Fig 6-16
High
Viscous drag
High
inertial drag
Burst Speed
Pike
Sustained Speed
Lobe Finned fishes - Sarcopterygia
Actinopterygia
Lungfish
Coelocanth
Australia
Africa
S. America
Aestivating African lungfish
Sketch sent to JLB Smith
Marjorie Courtney-Latimer
With the mounted S Africa
specimen
Oops! No internal organs or
skeleton!
1938
“I need a government plane!”
JLB Smith and flight crew
with 2nd coelocanth
Smith sleeps with his prize
The reward is presented
1997 - it happens again!
on a honeymoon trip to Indonesia!
See what paying
attention in
Vert Bio can do?