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 2Actinopterygia Ray-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 out Protrusible tube Advantage??

Sling-jaw Wrasse – Now that’s protrusible!

Pharyngeal Jaws Advantage??

Reproduction – most actinopterygians oviparous Marine- planktonicFreshwater & 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

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

Fig 6-13

High Viscous drag High inertial drag Fig 6-16

Pike Sustained Speed Burst Speed

Lobe Finned fishes - Sarcopterygia Actinopterygia Coelocanth Lungfish

S. America Africa Australia Aestivating African lungfish

Marjorie Courtney-Latimer With the mounted S Africa specimen Oops! No internal organs or skeleton! 1938 Sketch sent to JLB Smith

JLB Smith and flight crew with 2 nd coelocanth Smith sleeps with his prize “I need a government plane!”

The reward is presented

it happens again! on a honeymoon trip to Indonesia! See what paying attention in Vert Bio can do?