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VERTEBRATE ZOOLOGY (VZ Lecture22 – Spring 2012 Althoff - reference PJH Chapter 16)
Early Bird-like Forms Archaeopteryx Model of Microraptor (Dromaeosaurid) (American Museum of Natural History)
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(Opisthocomus hoazin)
Found in South America—primarily Brazil _______________ (Opisthocomus hoazin)
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Opisthocomus comes from the Greek meaning "wearing long hair behind"
___________________ Opisthocomus comes from the Greek meaning "wearing long hair behind" Nicknames include: __________ (because of their crocodilian odor & harsh monotonous call) __________ (because of it's clumsiness in the air and unusual diet) Nestlings have the ________ (2 per wing). When freightened they fall out of the nest (which is usually over water) and they use the claws to climb back up to the nest Has a diet of leaves…which means it has to have a way to breakdown cellulose “______________” stomach
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__________ (Opisthocomus hoazin)
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Hoatzin Skeleton modified to accommodate large crop – fermentation vat housing bacteria that help it breakdown cellulose to obtain “the good stuff” (proteins/sugars) in the plant material (not unlike what ungulates do) _________ bird species that has the “foregut fermentation” approach to handling plant material containing cellulose Rests on a _____________ while lengthy digestion takes place. The callosity is an elliptical, horny patch of skin lying over the rear tip of the sternum Feeds chicks _______________ mush of leaves Emu also has claws…3 per wing
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Late Jurassic (155-150 MYA) Germany
reptilian reptilian avian reptilian Archaeopteryx Late Jurassic ( MYA) Germany
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Archaeopteryx …. features
Feathers had much more differentiated feathers than either Caudipteryx and Protoarchaeopteryx—two species which appeared “after” Archaeopteryx Wing feathers differentiated into primaries and secondaries—nearly identical to extant birds ___________________ flight feathers—which enhances aerodynamics forces on the wing After finding the 7th specimen, revealed a rectangular sternum which would add surface area for flight muscle attachment…further evidence it probably could fly. Probably took off by running and flapping wings. Modern day “__________” equivalent would be roadrunner…a ground dwelling, cursorial predator that takes to the air to escape a predator
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6 5 4 3 2 1 TERRESTRIAL ARBOREAL Archaeopteryx Neornithes
Fig , p427 PJH
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Evolution of Derived Characters (Fig. 16-25)
Grasping arms, swivel wrist joint, _________ directed pubis Symmetrical vane feathers on wings and tail, down-like feathers on body, long tail Asymmetrical wing and tail feathers, longer arms, reduced tail
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RIGHT LATERAL VIEWS OF PELVIS
1 Ornithischia PUBUS ORIENTED POSTERIORLY Early archosaur Saurischia
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Pubis oriented posteriorly
Archosauromorphs Lepidosauromorphs ARCHOSAURS LEPIDOSAURS Ornithischia Saurischia BIRDS Pubis oriented posteriorly Fig. 16-2, p391 PJH
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Evolution of Derived Characters (Fig. 16-25)
Strut-like coracoid, fused pelvis, pygostyle, reduced foot claws Increased skeletal fusion, deeper sternum, alula, shorter tail Shorter back and tail, deeper sternum AND keel, more compact back and hip
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Strut-like coracoid 4
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fused caudal vertebrae
4 Fused pelvis (dorsal view) Pygostule fused caudal vertebrae (laternal view)
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Alula – feathers attached to “thumb”
that help with aerodynamics of flight… especially with slowing down without stalling 5
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Deeper sternum with keel
6 Arctic puffin
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