Transcript Archaeopteryx

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)
• Found in South America—primarily Brazil
_______________
(Opisthocomus hoazin)
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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 –
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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
reptilian
reptilian
avian
reptilian
Archaeopteryx
Late Jurassic (155-150 MYA) Germany
Archaeopteryx …. features
• Feathers had much more differentiated feathers than
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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
TERRESTRIAL
ARBOREAL
Archaeopteryx
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Fig. 16-25, p427 PJH
Neornithes
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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
1  RIGHT LATERAL VIEWS OF PELVIS
Ornithischia
PUBUS
ORIENTED
POSTERIORLY
Early archosaur
Saurischia
Archosauromorphs
ARCHOSAURS
Lepidosauromorphs
LEPIDOSAURS
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
4 Strut-like coracoid
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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
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Deeper sternum with keel
Arctic puffin