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The Sister Islands rock iguana (Cyclura nubila caymanensis) is critically endangered and endemic to the Caribbean islands Little Cayman and Cayman Brac. The Cayman Brac population and indeed the entire species is under threat from habitat destruction, invasive species, and anthropogenic impacts on the island. We assessed the genetic diversity, estimated effective population sizes, and tested for differentiation of populations between these two islands to inform potential future translocation should this be needed for the Cayman Brac population. Two mitochondrial DNA markers (cytochrome b and NADH subunit 4) and seven DNA microsatellite markers were used to assess the genetic diversity, genetic structure, demographic history, and effective population size of the two iguana populations. Mitochondrial DNA showed no genetic differentiation between populations; however, we found little to moderate divergence with microsatellites. We compared multiple demographic scenarios and revealed that ongoing gene flow is likely. The demographic history implied a significant genetic bottleneck around 10,000 years ago, coinciding with the sea level rise at the close of the last glacial period, and the start of the Holocene. Estimates of current effective population sizes indicate a small-scale number of breeders on each island of similar magnitude to the census mature population size (between 100 and 800 individuals). The relatively low differentiation between populations supports the possible development of active genetic management plans to manage the declining populations of the Sister Islands rock iguana. [ABSTRACT FROM AUTHOR]

Erymnochelys madagascariensis is a Critically Endangered turtle endemic to Madagascar. Anthropogenic activity has depleted the wild population by 70% in the last century, and effective conservation management is essential to ensuring its persistence. Captive breeding was implemented to augment depleted populations in the southern part of Ankarafantsika National Park (ANP), when no genetic data were available for E. madagascariensis. It is unknown how much of the natural population's diversity is encapsulated in captivity. We used eight microsatellite loci and fragments of two mitochondrial genes to identify the genetic structure of E. madagascariensis in the wild. Captive bred turtles were compared with wild populations in order to assess the representativeness of this ex situ conservation strategy for ANP. Six microsatellite clusters, ten cytochrome b, and nine COI haplotypes were identified across wild populations, with high genetic divergence found between populations in two groups of watersheds. Captive bred individuals represent three out of six sampled microsatellite clusters found in the wild and just one mitochondrial haplotype, possibly due to genetic drift. To improve genetic representation, the strategy of frequent interchange between captive and wild breeders within ANP should be revitalised and, as originally planned, hatchlings or juveniles should not be released beyond ANP. [ABSTRACT FROM AUTHOR]

Three species of boid snakes are recognized in Madagascar, namely the genus Sanzinia (one species and two subspecies) and the genus Acrantophis (two species). In the present study, we studied the patterns of genetic variation of these species across Madagascar using a fragment of the mitochondrial 16S rRNA gene in 77 specimens. To support the phylogenetic relationships of the lineages identified, three further gene fragments (cytochrome b, 12S rRNA and c-mos) were analyzed in a reduced but representative set of samples. The results obtained corroborate that the genus Sanzinia includes two highly divergent mitochondrial lineages that evolved independently from each other on the east versus the west side of Madagascar. Each of these lineages presents a further subdivision that separates northern from southern groups. The nuclear marker showed no variation among the Malagasy boas, indicating either very low substitution rates in this gene or relatively recent speciation events coupled with high mitochondrial substitution rates. Because the broad geographic sampling detected no admixture among haplotypic lineages within Sanzinia, it is hypothesized that these may represent distinct species. Deviant haplotypes of snakes morphologically similar to Acrantophis dumerili indicate that this taxon may be a complex of two species as well. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95, 640–652. [ABSTRACT FROM AUTHOR]

Madagascar is a biodiversity hotspot particularly rich in amphibian diversity and only a few charismatic Malagasy amphibians have been investigated for their population-level differentiation. The Mantella madagascariensis group is composed of two rainforest and three swamp forest species of poison frogs. We first confirm the monophyly of this clade using DNA sequences of three nuclear and four mitochondrial genes, and subsequently investigate the population genetic differentiation and demography of the swamp forest species using one mitochondrial, two nuclear and a set of nine microsatellite markers. Our results confirm the occurrence of two main mitochondrial lineages, one dominated by Mantella aurantiaca (a grouping supported also by our microsatellite-based tree) and the other by Mantella crocea + Mantella milotympanum. These two main lineages probably reflect an older divergence in swamp Mantella. Widespread mitochondrial introgression suggests a fairly common occurrence of inter-lineage gene flow. However, nuclear admixture seems to play only a limited role in this group, and the analyses of the RAG-1 marker points to a predominant incomplete lineage sorting scenario between all five species of the group, which probably diverged relatively recently. Our demographic analyses show a common, severe and recent demographic contraction, inferred to be in temporal coincidence with the massive deforestation events that took place in the past 1000 years. Current data do not allow to conclusively delimit independent evolutionary units in these frogs, and we therefore refrain to suggest any taxonomic changes. [ABSTRACT FROM AUTHOR]