Why are there so many types of lizards?

Researchers have sequenced the complete genetic code -- the genome -- of several vertebrate species from Panama. They found that changes in genes involved in the interbrain (the site of the pineal gland and other endocrine glands), for color vision, hormones and the colorful dewlap that males bob to attract females, may contribute to the formation of boundaries between species. Genes regulating limb development also evolved especially quickly.
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Playing both ends: Amphibian adapted to varied evolutionary pressures

Caecilian, Siphonops annulatus, a limbless amphibian found throughout Brazil, has a concentration of enlarged mucous glands in its head region and a concentration of enlarged poison glands in its posterior region. These concentration appear to have evolved from different selective pressures: the ability to tunnel into the ground and to defend oneself from predators.
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