Differentiation in the genera Enyalius and Strobilurus (Iguanidae): implications for pleistocene climatic changes in Eastern Brazil

Abstract

Geographic variations in meristic and morphometric characters are examined to delimit the taxa of the forest-restricted genus Enyalius in eastern Brazil Eight taxa are recognized. Phenetic affinities among these are described by multiple discriminant analysis and Wagner networks based on separate morphological data sets. A phylogeny is proposed, and a sequence of al opatric differentiations is hypothesized. The locations of refugia of the Brazilian Atlantic forest during drier cliiiatic periods are hypothesized from present variation in vegetation and precipitation: Santa Catarina refuge, around Baías de Paranaguá and São Francisco and adjacent slopes of Serra do Mar; São Paulo refuge, Serra do Mar between Paranapiacaba and São Sebastião; Bocaina refuge, around Baía da Ilha Grande; Mantiqueira refuge, on Serra da Mantiqueira; Órgãos refuge, on Serra dos Órgãos; Southern Espírito Santo refuge, in the mountains south of Rio Doce; Northern Espírito Santo refuge, on the coastal plain north of Rio Doce; Salvador refuge, around Baía de Todos os Santos; Pernambuco refuge, along coast of northern Alagoas and southern Pernambuco; Upper Rio Doce refuge, near the headwaters in Minas Gerais. Locations of the hypothesized refugia are compared with the geographical separation in Enyalius proposed to have preceded differentiation. Differentiation in Enyalius is most interpretable with reference to past forest refugia separated by corridors of open vegetation. Geographic variation in Strobilurus torquatus in northeastern Brazil requires similar conclusions.