Evolution of

Geology 331 , the first . Its is nearly identical to . Another view of Archaeopteryx

Yours truly with Archaeopteryx in , June 1998 Archaeopteryx carcass in a salty lagoon, 160 MY ago Archaeopteryx Archaeopteryx show evidence of behaviors similar to birds, particularly complex nesting behavior. , , died while sitting on Recovering the seen in last slide Oviraptor sitting on the sitting on the nest Evidence for theropod ancestry of birds

• Morphologic similarities • Cladistic analysis • Feathered from • Dino : http://www.cbsnews.com/video/watch/?id=5658225n&tag=cbsnewsSidebarArea.0 The theropod and the theropod The theropod and the Jurassic Archaeopteryx. Why is the best candidate for a theropod ancestor younger than the first bird? Dromaeosaurids (within Maniraptorans), including Velociraptor must have originated in the Jurassic, but were not preserved

Ghost Lineage *


Prothero, 2007 Anchiornis (“near bird”), a feathered maniraptoran discovered in 2009. Closes the time gap between maniraptorans and Archaeopteryx. of a living bird

Cladistic analysis supports the of birds from ancestors like Coelophysis, Allosaurus, and Velociraptor

Morphologic features supporting from theropods Classification vs. Phylogeny

• Linnean Classification • or Reptilia no categories, but a nested hierarchy shows evolutionary Class Dinosauria relationships Class Aves Reptilia Archaeopteryx Diapsida Archosauria Linnean scheme Dinosauria obscures evolutionary relationships. Aves Archaeopteryx Classification vs. Phylogeny Pros Cons • Linnean scheme fails to • Linnean scheme is simple show evolutionary and places major groups relationships between at a high taxonomic level. groups. • Cladistics scheme shows • Cladistics scheme is evolutionary relationships cumbersome because of in a nested hierarchy. so many names. Lack of ranks is confusing to non- specialists.

Conclusion: Classification and Phylogenetics serve different purposes. Linnean Classification


Prothero, 2007 on display in T. rex Sue at the Field

Clavicles on T. rex Peter Larson showing the attached to the shoulder blades of T. rex. Healed broken ribs Perching of birds A feathered theropod showing evolution of improved capabilities in birds

Cretaceous toothed bird with Cretaceous toothed bird with wing claws No toothed birds survived the K/T event Where did birds come from? They evolved from theropod dinosaurs. from China, 2002

Another feathered dinosaur from Laioning, China Birds evolved from feathered theropods

Feathered theropods Feathered theropod dinosaur from China, 1998 Reconstruction of feathered dinosaur Fossilized in feathered dinosaur Chinese dromaeosaur theropod, 1999 Chinese dromaeosaur theropod skeleton with preserved Closeup of feathers on Chinese dromaeosaur theropod Complete skeleton of Chinese dromaeosaur theropod with feathers, at the bottom. Tail of Chinese dromaeosaur showing bundles of bony ligaments for stiffening the tail, typical of theropods. Forearm of a therizinosaur theropod with preserved feathers A simplified cladogram showing the systematic position of huali among the .

X Xu et al. 484, 92-95 (2012) doi:10.1038/nature10906 Selected elements of Yutyrannus huali

X Xu et al. Nature 484, 92-95 (2012) doi:10.1038/nature10906 Actual fossil birds from China that are different from feathered dinos , a Cretaceous aquatic, toothed bird How the 'terror bird' tore its prey: South American predator, 60Ma-2Ma