Abstract

The Lesser Antilles, in the Eastern Caribbean, is inhabited by threeIguanaspecies: the Lesser Antillean iguanaIguana delicatissima, which is endemic to the northernmost islands of the Lesser Antilles, the introduced common iguana from South America,Iguana iguana iguana, represented also by the two newly described endemic subspeciesIguana iguana sanctaluciaefrom Saint Lucia andIguana iguana insularisfrom Saint Vincent and the Grenadines, and Grenada, and the introducedIguana rhinolophafrom Central America. Drawing on both morphological and genetic data, this paper describes theIguanapopulations from Saba and Montserrat as a new species,Iguana melanoderma. This species is recognized on the basis of the following combination of characteristics: private microsatellite alleles, unique mitochondrial ND4 haplotypes, a distinctive black spot between the eye and tympanum, a dorsal carpet pattern on juveniles and young adults, a darkening of body coloration with aging (except for the anterior part of the snout), a black dewlap, pink on the jowl, the high number of large tubercular nape scales, fewer than ten medium sized-triangular dewlap spikes, high dorsal spikes, and lack of horns on the snout. This new melanistic taxon is threatened by unsustainable harvesting (including for the pet trade) and both competition and hybridization from escaped or released invasive alien iguanas (I. iguana iguanaandI. rhinolopha) from South and Central America, respectively. The authors call for action to conserveIguana melanodermain Saba and Montserrat and for further research to investigate its relationship to other melanistic iguanas from the Virgin Islands and coastal islands of Venezuela.