<div class="tree_txt_unlinked"><p>Ponginae contains a single genus, <em>Pongo</em>,
or the orangutans, found only in Asia. There are two forms: the
Sumatran orangutan and the Bornean orangutan, which likely diverged
about 1.5 Ma, though their taxonomic relationship remains debated. All
orangutans are extremely sexually dimorphic, with males about twice the
size of females. Unlike African apes, orangutans have high rounded
brain cases with poorly developed brow ridges, tall, narrow orbits set
close together, and a prognathic snout with a convex premaxilla. Their
molars have low cusps, covered covered in thick, pitted enamel for
opening the tough cases of some fruits. Their forelimbs are very long,
and their fingers very curved.</p>
<p><strong>Citations</strong>: Fleagle 1999</p>
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