Unequal degrees of taxonomic subdivision can pose problems for research that relies on cross-taxon comparisons of biogeographic patterns. Numerous species of lemurs have been described in recent years. These descriptions were unevenly distributed over the genera of lemurs as exemplified by the closely related mouse lemurs ( spp.) and dwarf lemurs ( spp.). According to previous studies, these genera display striking differences such as many versus few species, small versus large distributions, and small versus large mitochondrial divergence within and between species. We questioned if these differences reflect the biological reality or a biased taxonomic subdivision, which might be partially due to relatively small amounts of available genetic data from dwarf lemurs. We complemented existing datasets with genetic data from 51 dwarf lemurs from nine sites in southern Madagascar. We analyzed the mitochondrial gene and the nuclear loci , , and . Based on a comparison of mitochondrial genetic data from both genera, we delineated eight hypothetical subgroups within two recognized species. We used mitochondrial and nuclear data to reconstruct species trees and to estimate divergence times between species and subgroups. We further performed Bayesian species delimitations based on nuclear sequence data from subgroups. Strong signals in mitochondrial and nuclear data indicate the existence of deeply divergent, distinct groups within recognized species. Based on several lines of evidence, we conclude that the species diversity in has been underestimated so far. We delineate six species among the eight subgroups and provide a formal description for one new species.
Hibernation is an adaptive strategy some mammals use to survive highly seasonal or unpredictable environments. We present the first investigation on the transcriptomics of hibernation in a natural population of primate hibernators: Crossley's dwarf lemurs ( Cheirogaleus crossleyi ). Using capture–mark–recapture techniques to track the same animals over a period of 7 months in Madagascar, we used RNA‐seq to compare gene expression profiles in white adipose tissue (WAT) during three distinct physiological states. We focus on pathway analysis to assess the biological significance of transcriptional changes in dwarf lemur WAT and, by comparing and contrasting what is known in other model hibernating species, contribute to a broader understanding of genomic contributions of hibernation across Mammalia. The hibernation signature is characterized by a suppression of lipid biosynthesis, pyruvate metabolism and mitochondrial‐associated functions, and an accumulation of transcripts encoding ribosomal components and iron‐storage proteins. The data support a key role of pyruvate dehydrogenase kinase isoenzyme 4 ( PDK4 ) in regulating the shift in fuel economy during periods of severe food deprivation. This pattern of PDK4 holds true across representative hibernating species from disparate mammalian groups, suggesting that the genetic underpinnings of hibernation may be ancestral to mammals.
Fork-marked dwarf lemurs (Phaner spp.) of Madagascar and the needle-clawed galagos (Euoticus spp.) of Central-West Africa are two genera within the primate suborder Strepsirrhini. Despite their distant relationship, these genera share remarkably convergent anatomical, behavioural and ecological characteristics. However, like most nocturnal primates in sub-Saharan Africa they are poorly studied and little is known about the population estimates of both genera. I conducted surveys of wild populations of Phaner pallescens, P. parienti and P. furcifer in Madagascar as well as Euoticus elegantulus and E. pallidus in Cameroon. Six transects were established in Madagascar covering a total distance of 20 km, within which I encountered 52 fork-marked dwarf lemurs. In Cameroon three transects were established covering a total distance of 8.5 km, and 56 encounters of needle-clawed galagos were made. Population encounter rates of P. pallescens, P. parienti, P. furcifer, E. elegantulus and E. pallidus were 3.3, 2.4, 2.3, 9.9 and 8.3 individuals per kilometre, respectively. Compared to previous estimates of population encounter rates in other study sites, these values are lower. Low population encounter rates of fork-marked dwarf lemurs and needle-clawed galagos may be due to environmental and anthropogenic pressures at the study sites. Further ecological, behavioural and conservation studies are required for these genera.
Phaner and Euoticus are selective in their preferred habitats. They make use of planted trees. They show ecological plasticity with specialization regarding areas with trees greater than 10 m in height and a canopy.