Iguana 12.4 b&w text 240 IGUANA • VOLUME 12, NUMBER 4 • DECEMBER 2005 GUTSCHE R O B ER T PO W EL L Norops utilensis 1 is endemic to the Isla de Utila (Islas de la Bahia, Honduras). Discovered in 1995, it is a poorly known member of the N. pentaprion-group. In contrast to the other members of the group, all of which live in broadleaf trop- ical rain forests, N. utilensis dwells exclusively in a highly spe- The World’s Most Endangered Anole? Alexander Gutsche Department of Biology, Sensory Biology, Humboldt-University Berlin, Germany Photographs by the author unless otherwise indicated. IGUANA • VOLUME 12, NUMBER 4 • DECEMBER 2005 241WORLD’S MOST ENDANGERED ANOLE? � 1 In 1987, Craig Guyer and Jay Savage (Systematic Zoology 35: 509–531) proposed a classification of anoles that included formal recognition of several distinct genera within the group. One of these genera was Norops, to which the Utila Anole has been assigned. Although recognition of those genera has been strongly advocated by some authorities, others, who would refer to the Utila Anole as Anolis utiliensis, prefer a more conservative approach until a number of concerns regarding generic relationships among anoles have been addressed. Those concerns were best summarized by Ernest Williams in 1989 (In: C.A. Woods (ed.), Biogeography of the West Indies: Past, Present, and Future. Sandhill Crane Press, Gainesville, Florida). An adult female Utila Anole (Norops utilensis). Because suitable nesting holes are a limited resource in the mangrove forests, Utila Anoles may lay their eggs communally. The two shells in this nest hole in a hollow Red Mangrove root are remains of eggs that were undoubtedly laid by two different females. cialized habitat – the salty mangrove swamps of Isla Utila (see Iguana 12:142 for detailed descriptions of the habitat). Norops utilensis is a medium-sized anole, reaching about 150 mm in total length, most of it tail (maximum known snout-vent length = 59 mm). They are well-camouflaged due to a lichenose gray-brown dorsal pattern, which makes them difficult to detect as they adhere closely to the surface of man- grove trunks and branches. A red dewlap is present in both 242 IGUANA • VOLUME 12, NUMBER 4 • DECEMBER 2005 GUTSCHE One-day-old hatchling Utila Anole at the egg-laying site (tree hole in a Rhizophora mangle root). Natural habitat of Norops utilensis at the type locality: A mixture of Black (Avicennia germinans) and Red Mangroves (Rhizophora mangle). A Common Black Hawk (Buteogallus anthracinus) in the Big Bight, one of the areas where Norops utilensis is known to occur. Although these hawks typically prefer larger prey (including iguanas), they might occa- sionally take an anole. Predation pressure from visual predators may contribute to the cryptic coloration and shy behavior of Utila Anoles. R O B ER T PO W EL L IGUANA • VOLUME 12, NUMBER 4 • DECEMBER 2005 243WORLD’S MOST ENDANGERED ANOLE? males and females, but is much larger in males and forms a bright shining signal flag when they respond to intruders or advertise their presence to females. Utila anoles are entirely arboreal and live and behave in a gecko-like fashion, pressing their bodies tightly against the substrate as they cling closely to the surface of mangrove trunks and twigs at heights ranging from 1–7 m above the waterlogged ground. Like most anoles, females lay a single egg at a time, using suitable, detritus-filled tree holes. These tree holes are a limited resource within the mangroves; consequently, communal nest- ing appears to be common. Although the local climate is strictly seasonal (with distinct wet and dry seasons), N. utilensis repro- duces throughout the year. Most reproductive activity occurs during the rainy season (when food is presumably most plenti- ful), but individuals quickly become reproductively active dur- ing periods in the dry season when favorable conditions exist. Norops utilensis is not common in the mangrove swamps. Since its discovery, only 13 specimens have been detected at two localities. Due to the specialized and severely limited habi- tat, apparently low population sizes, and ongoing human threats to the habitat (e.g., deforestation and use of the man- grove swamps for solid waste disposal), N. utilensis meets all of the IUCN Red List criteria (http://www.redlist.org/info/cate- gories_criteria.html) to qualify for critically endangered status. As for so many other threatened insular endemics, the best chances for long-term survival lie in controlling the size of the human population, education, and preservation of critical habi- tats (see Iguana 10:28–37 and Iguana 11:206–211 for addi- tional pertinent information). References Gutsche, A., J.R. McCranie, and K. Nicholson. 2004. Field observations on a nesting site of Norops utilensis Köhler, 1996 (Reptilia, Squamata) with comments about its conservation status. Salamandra 40:297–302. Köhler, G. 1996. A new species of anole of the Norops pentaprion-group from Isla de Utila, Honduras. Senck. biol. 75:23–31. McCranie, J.R., L.D. Wilson, and G. Köhler. 2005. Amphibians & Reptiles of the Bay Islands and Cayos Cochinos, Honduras. Bibliomania!, Salt Lake City, Utah. Utila Anoles are associated strictly with mangrove stands near the Big Bight. JO E B U R G ES S Utila Anoles rely heavily on crypsis to avoid predators and rarely extend their dewlaps (see also inside front cover).