Evolutionary History

 

Shared Derived Traits

Their appearance consists of a narrow band that runs in an upside down u-shape on their chests and a white band on their beaks. They also lack feathers on their legs and face. Unique behavior traits are that they have loud donkey like braying calls and they nest in burrows.

Shared Ancestral Traits

Wings modified into flippers, with very flat bones and the wrist and elbow joints fused. Their bones are solid to decrease buoyancy. Increased density of feathers. Countershading for camouflage with white under bellies and black backs. Legs positioned as far back as possible. Stiff and springy feathers to trap air while diving.    

Birds&Vertebrate Phylogeny

Bird Phylogeny

Figure 1.3: Phylogenetic tree of related neoaves

Penguin Phylogeny

 

Sources

http://tolweb.org/treehouses/?treehouse_id=3029

Kinzey, W.G. (1997). New World Primates, Ecology, Evolution and Behavior. New York: Aldine de Gruyter.

http://www.honoluluzoo.org/spider_monkey.htm