title: Molecular data reveal spatial and temporal patterns of diversification and a cryptic new species of lowland Stenocercus Duméril & Bibron, 1837 (Squamata: Tropiduridae).
abstract: Phylogenetic studies have uncovered biogeographic patterns and the associated diversification processes of Neotropical wet forest taxa, yet the extensive open and drier biomes have received much less attention. In the Stenocercus lizard radiation, restricted sampling and phylogenetic information have limited inferences about the timing, spatial context, and environmental drivers of diversification in the open and dry lowland settings of eastern and southern South America. Based on new DNA sequence data of previously unsampled species, we provide an updated historical biogeographic hypothesis of Stenocercus. We infer phylogenetic relationships, estimate divergence times, and track ancestral distributions, asking whether cladogenetic events within the genus correlate to reported shifts in South American landscapes during the past 30millionyears, focusing in the open and drier areas. To examine correlations between genetic and ecological divergence, we extracted environmental data from occurrence records and estimated climatic envelopes occupied by lowland taxa. Our results suggest that Stenocercus began to diversify around the South American Midwest by the late Oligocene. We recovered two main lowland and two main Andean clades within the genus; within both Andean clades, most cladogenetic events date back to the Miocene, synchronously with the most intense phase of Andean uplift. In the western clade of lowland Stenocercus, species ranges and divergence times are consistent with major landscape shifts at the upper Guaporé and Paraguay River basins as a result of Andean orogeny, suggesting vicariant speciation. By contrast, in the 'horned' lowland clade, we find evidence that dispersal and ecological differentiation have shaped species divergences and current ranges in the Brazilian Cerrado, Caatinga, Pampas and Atlantic Forest, possibly under a vanishing refuge scenario. Lastly, our phylogenetic results indicate two divergent clades within the formerly recognized taxon S. sinesaccus, and further evaluation of morphological data corroborates the existence of a distinct, new species of Stenocercus, here described. The new taxon occurs in the Chapada dos Parecis massif in the Brazilian states of Mato Grosso and Rondônia.
authors.affiliation: Laboratório de Herpetologia, Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, SP, Brazil. Electronic address: tropidurus@gmail.com.
authors.forename: Mauro
authors.initials: M
authors.lastname: Teixeira
authors.affiliation: Department of Biology, City College and Graduate Center, City University of New York, New York, NY 10031, USA.
authors.forename: Ivan
authors.initials: I
authors.lastname: Prates
authors.affiliation: Laboratório de Herpetologia, Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, SP, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Nisa
authors.affiliation: Departamento de Ciências Básicas e Produção Animal, Faculdade de Agronomia, Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, MT, Brazil.
authors.forename: Nathalia Suzan Camarão
authors.initials: NS
authors.lastname: Silva-Martins
authors.affiliation: Departamento de Ciências Básicas e Produção Animal, Faculdade de Agronomia, Medicina Veterinária e Zootecnia, Universidade Federal de Mato Grosso, 78060-900 Cuiabá, MT, Brazil.
authors.forename: Christine
authors.initials: C
authors.lastname: Strüssmann
authors.affiliation: Laboratório de Herpetologia, Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, SP, Brazil.
authors.forename: Miguel Trefaut
authors.initials: MT
authors.lastname: Rodrigues
mesh_terms: D000818:Animals; D001483:Base Sequence; D001938:Brazil; D049810:Genetic Speciation; D014644:Genetic Variation; D008116:Lizards / Q000145:classification* / Q000235:genetics*; D010239:Paraguay; D010802:Phylogeny; D058974:Phylogeography; D065947:Rainforest; D013020:South America; D014329:Tropical Climate
keywords: Andes; Climatic niche; Historical biogeography; Iguania; Stenocercini; Taxonomy