Molecular phylogeny, species limits, and biogeography of the Brazilian endemic lizard genus Enyalius (Squamata: Leiosauridae): an example of the historical relationship between Atlantic Forests and Amazonia.

The endemic Brazilian Enyalius encompasses a diverse group of forest lizards with most species restricted to the Atlantic Forest (AF). Their taxonomy is problematic due to extensive variation in color pattern and external morphology. We present the first phylogenetic hypothesis for the genus based on 2102 bp of the mtDNA (cyt-b, ND4, and 16S) and nuclear (c-mos) regions, uncovering all previously admitted taxa (9 spp). Different methods of tree reconstruction were explored with Urostrophus vautieri, Anisolepis grilli and A. longicauda as outgroups. The monophyly of Enyalius and its split into two deeply divergent clades (late Oligocene and early Miocene) is strongly supported. Clade A assembles most lineages restricted to south and southeastern Brazil, and within it Enyalius brasiliensis is polyphyletic; herein full species status of E. brasiliensis and E. boulengeri is resurrected. Clade B unites the Amazonian E. leechii as sister-group to a major clade containing E. bilineatus as sister-group to all remaining species from northeastern Brazil. We detected unrecognized diversity in several populations suggesting putative species. Biogeographical analyses indicate that Enyalius keeps fidelity to shadowed forests, with few cases of dispersal into open regions. Ancient dispersal into the Amazon from an AF ancestor may have occurred through northeastern Brazil.

Comparative cytogenetics and supernumerary chromosomes in the Brazilian lizard genus Enyalius (Squamata, Polychrotidae).

Cytogenetical analyses based on conventional and differential staining were performed for the first time on five species of the Brazilian lizard genus Enyalius: E. bibronii, E. bilineatus, E. iheringii, E. leechii, and E. perditus. The species share a similar 2n = 36 (12M + 24m) karyotype, comprised of 12 metacentric or submetacentric macrochromosomes, except for an acrocentric pair 6 that characterizes E. bibronii. The 24 microchromosomes were acrocentrics, but in E. perditus two meta/submetacentric microchromosome pairs were unambiguously identified. Karyotypes with 2n = 37 and 2n = 37/38 chromosomes were also observed in some specimens of E. bilineatus as a result of the presence of supernumerary chromosomes (Bs). Ag-NORs were always located at the distal region of the long arm of the submetacentric pair 2. The constitutive heterochromatin was mostly restricted to the pericentromeric regions of some macrochromosomes and microchromosomes. A XX:XY mechanism of sex determination with a dot-like Y microchromosome occurs in E. bilineatus, E. leechii, and E. perditus.