Genetic Differentiation and Demographic History of the Northern Rufous Mouse Lemur (<Emphasis Type="Italic">Microcebus tavaratra</Emphasis>) Across a Fragmented Landscape in Northern Madagascar

Phylogeographic barriers, together with habitat loss and fragmentation, contribute to the evolution of a species’ genetic diversity by limiting gene flow and increasing genetic differentiation among populations. Changes in connectivity can thus affect the genetic diversity of populations, which may influence the evolutionary potential of species and the survival of populations in the long term. We studied the genetic diversity of the little known Northern rufous mouse lemur (Microcebus tavaratra), endemic to Northern Madagascar. We focused on the population of M. tavaratra in the Loky–Manambato region, Northern Madagascar, a region delimited by two permanent rivers and characterized by a mosaic of fragmented forests. We genotyped 148 individuals at three mitochondrial loci (D-loop, cytb, and cox2) in all the major forests of the study region. Our analyses suggest that M. tavaratra holds average genetic diversity when compared to other mouse lemur species, and we identified two to four genetic clusters in the study region, a pattern similar to that observed in another lemur endemic to the region (Propithecus tattersalli). The main cluster involved samples from the two mountain forests in the study region, which were connected until recently. However, the river crossing the study region does not appear to be a strict barrier to gene flow in M. tavaratra. Finally, the inferred demographic history of M. tavaratra suggests no detectable departure from stationarity over the last millennia. Comparisons with codistributed species (P. tattersalli and two endemic rodents, Eliurus spp.) suggest both differences and similarities in the genetic clusters identified (i.e., barriers to species dispersal) and in the inferred demographic history. These comparisons suggest that studies of codistributed species are important to understand the effects of landscape features on species and to reconstruct the history of habitat changes in a region.     

Genetic and morphological diversity of mouse lemurs (Microcebus spp.) in northern Madagascar: The discovery of a putative new species?

Tropical forests harbor extremely high levels of biological diversity and are quickly disappearing. Despite the increasingly recognized high rate of habitat loss, it is expected that new species will be discovered as more effort is put to document tropical biodiversity. Exploring under‐studied regions is particularly urgent if we consider the rapid changes in habitat due to anthropogenic activities. Madagascar is known for its extraordinary biological diversity and endemicity. It is also threatened by habitat loss and fragmentation. It holds more than 100 endemic primate species (lemurs). Among these, Microcebus (mouse lemurs) is one of the more diverse genera. We sampled mouse lemurs from several sites across northern Madagascar, including forests never sampled before. We obtained morphological data from 99 Microcebus individuals; we extracted DNA from tissue samples of 42 individuals and amplified two mitochondrial loci (cytb and cox2) commonly used for species identification. Our findings update the distribution of three species (Microcebus tavaratra, Microcebus arnholdi, and Microcebus mamiratra), including a major increase in the distribution area of M. arnholdi. We also report the discovery of a new Microcebus lineage genetically related to M. arnholdi. Several complementary approaches suggest that the newly identified Microcebus lineage might correspond to a new putative species, to be confirmed or rejected with additional data. In addition, morphological analyses showed (a) clear phenotypic differences between M. tavaratra and M. arnholdi, but no clear differences between the new Microcebus lineage and the sister species M. arnholdi; and (b) a significant correlation between climatic variables and morphology, suggesting a possible relationship between species identity, morphology, and environment. By integrating morphological, climatic, genetic, and spatial data of two northern Microcebus species, we show that the spatial distribution of forest‐dwelling species may be used as a proxy to reconstruct the past spatial changes in forest cover and vegetation type.     

Highly Variable Densities and a Decline in Critically Endangered Golden-Crowned Sifaka (Propithecus tattersalli) Abundance from 2008–2018

International Journal of Primatology - Animal abundance is determined by a number of factors, including vegetation structure, food availability and quality, human activities, predation risk, and...