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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 Sarcopterygia Lung fish Fig 6-3
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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 • Sarcopterygia • Lung fish Fig 6-3 • Coelocanths Fig 6-4 • Tetrapods • Actinopterygia • Ray-finned fishes
Trends in Actinopterygian Evolution Fig 6-2, 6-8 • 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 Physostomous Physoclistous Ovale
Are mammals on this cladogram? If so where? • What is the major difference between ostracoderms and placoderms? • For actinopterygians, what is the ancestral condition in terms of scale type and tail type? • Sharks maintain neutral buoyancy without a swim bladder. How? • What would you predict about the organs for maintaining neutral buoyancy in bottom-dwelling rays and actinopterygians? • If a physoclistous fish were swimming to deeper depths, what would the ovale of the swim bladder be doing?
Evolution of protrusible jaws and pharyngeal jaws Scissors = gar Maxilla rotates out – trout Premaxilla slides out Protrusible tube Advantage??
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
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 6-16 High inertial drag High Viscous drag
Burst Speed Sustained Speed Pike
Lobe Finned fishes - Sarcopterygia Actinopterygia Lungfish Coelocanth
Aestivating African lungfish Australia Africa S. America
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
1997 - it happens again! on a honeymoon trip to Indonesia! See what paying attention in Vert Bio can do?