Osteichthyes - >27,000 bony fishes, 13,000 herps, 9000 birds, 4800 mammals

Bony Fish Characteristics–Endochondral bone

Bony operculumCovering gills

Extinct AntecedentsPlacoderms (Arthrodires)

Neck Joint

Two major branchesOf Osteichthyes1. Sarcopterygia

Lung fish Fig 6-3Coelocanths Fig 6-4Tetrapods

2 ActinopterygiaRay-finned fishes

Trends in Actinopterygian Evolution Fig 6-2, 6-8

1) Heavy body armor light overlapping scales Ganoid scales cycloid, ctenoid

Ctenoid

2) Heterocercal Homocercal tail

Heterocercal tail of Paddlefish Homocercal tail of swordfish

Gar

Bowfin (Amia)

3) Development of gas/swim bladder for buoyancy Fig 4-3

PhysoclistousPhysostomous

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 outProtrusible tube

Advantage??

Sling-jaw Wrasse – Now that’s protrusible!

Pharyngeal JawsAdvantage??

Reproduction – most actinopterygians oviparous

Marine- planktonic Freshwater & nest–guarding Marine - demersal

Planktonic larvae of marine fish

Note adaptations to blend in with planktonOr 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

Anguilliform

Carangiform

Ostraciform

Swimming styles and swimming efficiency Fig 6-14, 6-15, 6-16

Fig 6-13

HighViscous drag

High inertial drag

Fig 6-16

Pike

Sustained SpeedBurst Speed

Lobe Finned fishes - Sarcopterygia

Actinopterygia

Coelocanth

Lungfish

S. America

Africa

Australia Aestivating African lungfish

Marjorie Courtney-LatimerWith the mounted S Africa specimenOops! No internal organs or skeleton!

1938

Sketch sent to JLB Smith

JLB Smith and flight crewwith 2nd coelocanth

Smith sleeps with his prize

“I need a government plane!”

The reward is presented

1997 - it happens again! on a honeymoon trip to Indonesia!

See what paying attention in Vert Bio can do?