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)

(Opisthocomus hoazin) Found in South America—primarily Brazil _______________ (Opisthocomus hoazin)

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

__________ (Opisthocomus hoazin)

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

Late Jurassic (155-150 MYA) Germany reptilian reptilian avian reptilian Archaeopteryx Late Jurassic (155-150 MYA) Germany

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

6 5 4 3 2 1 TERRESTRIAL ARBOREAL Archaeopteryx Neornithes Fig. 16-25, p427 PJH

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

 RIGHT LATERAL VIEWS OF PELVIS 1 Ornithischia PUBUS ORIENTED POSTERIORLY Early archosaur Saurischia

Pubis oriented posteriorly Archosauromorphs Lepidosauromorphs ARCHOSAURS LEPIDOSAURS Ornithischia Saurischia BIRDS Pubis oriented posteriorly Fig. 16-2, p391 PJH

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

Strut-like coracoid 4

fused caudal vertebrae 4 Fused pelvis (dorsal view) Pygostule  fused caudal vertebrae (laternal view)

Alula – feathers attached to “thumb” that help with aerodynamics of flight… especially with slowing down without stalling 5

Deeper sternum with keel 6 Arctic puffin