We tend to think the contours of biodiversity are well known, especially in extensively studied areas. However, this is not necessarily the case and sometimes strikingly new species are discovered even in well-trod areas. A case in point is the country of the Dominican Republic, which has been thoroughly studied by biologists for more than 40 years, particularly by herpetologists who have exhaustively catalogued the reptiles and amphibians there for several decades.
Particularly well-studied have been small lizards in the genus Anolis, commonly called anoles. These are very common lizards on islands throughout the Caribbean and in the southeastern United States where the green anole, a photogenic species with pinkish-red throat fan (called a dewlap), is widely known.
Because of their abundance and species richness, anoles have become a workhorse of field biologists, who have learned much about evolution and ecology from studies of the 150 Caribbean anole species (another 250 occur in Central and South America). The more than 40 species of Anolis on the island of Hispaniola (the island containing Haiti and the Dominican Republic) have been particularly popular with researchers, and no new species has been found there since the early 1980's (not including several species that have been newly recognized when formerly widespread species have been subdivided into multiple species). Herpetologists thought the diversity of Hispaniola was well understood. "Never in a million years would I have thought that a completely new species of anoles, something unlike anything previously known, would be discovered on that island," said Jonathan Losos, Curator of Herpetology at the Harvard's Museum of Comparative Zoology and a professor in the Department of Organismic and Evolutionary Biology.
And then along came Miguel Landestoy. Self-taught, the Dominican naturalist and photographer makes his living leading photographic and nature field trips and conducting conservation research throughout the Dominican Republic. On one trip in 2007 to the western edge of the Dominican Republic, very near the border with Haiti, Landestoy spied, high in a tree, a large anole clearly unlike any other he had ever seen. He managed to capture the animal, but only briefly, and it escaped before he could take a suitable photo. But he knew it was something different, something unknown, and so he kept returning to the forest.
And then one day, several years later, he saw another. And this time he got the photo. He quickly sent it to several American herpetologists, including Luke Mahler, then a graduate student in Losos' lab and now an assistant professor at the University of Toronto. Mahler took one look at the photo and his jaw dropped. He showed it to Losos, and asked him where he thought it was from. "I had no idea," Losos says, "and guessed somewhere high in the Andes, where they are still finding new species. It never even crossed my mind that it might be from Hispaniola."
By the end of the week, Mahler was on a plane to the Dominican Republic for a whirlwind, 36-hour trip to secure a specimen. Landestoy met Mahler at the airport and the two quickly drove the five hours to the site. Luck was with them and they were able to capture two lizards in an all-night search, then motor directly back to the airport so that Mahler could fly back to Boston in time to prepare for his Monday teaching duties.
Mahler's detailed anatomical analyses documented the uniqueness of the new species. Colleagues Richard Glor and his lab sequenced the DNA to place the species in the evolutionary tree of these lizards. Their results indicate that the species is related to other large lizards from the same island. And thus Anolis landestoyi came into being with publication of the paper by Mahler and colleagues in The American Naturalist.
As well as demonstrating that there are new species to find even in well-studied areas, Anolis landestoyi's discovery yields important findings about the evolution of Caribbean Anolis lizards. In evolutionary circles, anoles are famous for the evolution of many different types of habitat specialists on a single island--one species adapted to live in the tree canopy, another in the grass, a third on twigs, and so on. What is particularly unusual about anole evolution, however, is that the same set of habitat specialists has evolved independently on each of the major islands of the Caribbean (Cuba, Hispaniola, Jamaica and Puerto Rico). The phenomenon of convergent evolution--in which species independently evolve the same traits--is well known, but convergence of entire suites of habitat specialists is much less documented, and Caribbean anoles are the textbook example of this phenomenon.
However, even in these anoles, there were some exceptions, types of habitat specialists that had evolved on one island, but had no parallels on any of the other islands. One particularly interesting example were large, slow moving anoles, very similar to true chameleons, only found on Cuba. Or so we thought. It turns out that Anolis landestoyi is very similar in both anatomy and habits to the Cuban species, showing that the communities of lizards on these islands are even more similar than previously realized.
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Discovery of a giant chameleon-like lizard (Anolis) on Hispaniola and its significance to understanding replicated adaptive radiations. American Naturalist.
D. Luke Mahler, Shea M. Lambert, Anthony J. Geneva, Julienne Ng, S. Blair
Hedges, Jonathan B. Losos, and Richard E. Glor
Contact Information:
Luke Mahler, University of Toronto: luke.mahler@utoronto.ca
Jonathan Losos, Harvard University: jlosos@oeb.harvard.edu
Richard Glor: University of Kansas: glor@ku.edu