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. https://www.sciencedaily.com/releases/2018/02/180223151844.htm