The genomic diversity of the Eliurus genus in northern Madagascar with a putative new species.

Madagascar exhibits extraordinarily high level of species richness and endemism, while being severely threatened by habitat loss and fragmentation (HL&F). In front of these threats to biodiversity, conservation effort can be directed, for instance, in the documentation of species that are still unknown to science, or in investigating how species respond to HL&F. The tufted-tail rats genus (Eliurus spp.) is the most speciose genus of endemic rodents in Madagascar, with 13 described species, which occupy two major habitat types: dry or humid forests. The large species diversity and association to specific habitat types make the Eliurus genus a suitable model for investigating species adaptation to new environments, as well as response to HL&F (dry vs humid). In the present study, we investigated Eliurus spp. genomic diversity across northern Madagascar, a region covered by both dry and humid fragmented forests. From the mitochondrial DNA (mtDNA) and nuclear genomic (RAD-seq) data of 124 Eliurus individuals sampled in poorly studied forests of northern Madagascar, we identified an undescribed Eliurus taxon (Eliurus sp. nova). We tested the hypothesis of a new Eliurus species using several approaches: i) DNA barcoding; ii) phylogenetic inferences; iii) species delimitation tests based on the Multi-Species Coalescent (MSC) model, iv) genealogical divergence index (gdi); v) an ad-hoc test of isolation-by-distance within versus between sister-taxa, vi) comparisons of %GC content patterns and vii) morphological analyses. All analyses support the recognition of the undescribed lineage as a putative distinct species. In addition, we show that Eliurus myoxinus, a species known from the dry forests of western Madagascar, is, surprisingly, found mostly in humid forests in northern Madagascar. In conclusion, we discuss the implications of such findings in the context of Eliurus species evolution and diversification, and use the distribution of northern Eliurus species as a proxy for reconstructing past changes in forest cover and vegetation type in northern Madagascar.

Dietary flexibility of the greater bamboo lemur (Prolemur simus), a specialized feeder, in eastern Madagascar.

The degree of dietary flexibility in primates is species specific; some incorporate a wider array of resources than others. Extreme interannual weather variability in Madagascar results in seasonal resource scarcity which has been linked to specialized behaviors in lemurs. Prolemur simus, for example, has been considered an obligate specialist on large culm bamboo with >60% of its diet composed of woody bamboos requiring morphological and physiological adaptations to process. Recent studies reported an ever-expanding list of dietary items, suggesting that this species may not be an obligate specialist. However, long-term quantitative feeding data are unavailable across this species' range. To explore the dietary flexibility of P. simus, we collected data at two northern sites, Ambalafary and Sahavola, and one southern site, Vatovavy, from September 2010 to January 2016 and May 2017 to September 2018, respectively. In total, we recorded 4022 h of behavioral data using instantaneous sampling of adult males and females from one group in Ambalafary, and two groups each in Sahavola and Vatovavy. We recorded 45 plant species eaten by P. simus over 7 years. We also observed significant differences in seasonal dietary composition between study sites. In Ambalafary, bamboo was the most frequently observed resource consumed (92.2%); however, non-bamboo resources comprised nearly one-third of the diet of P. simus in Sahavola and over 60% in Vatovavy. Consumption of all bamboo resources increased during the dry season at Ambalafary and during the wet season at Vatovavy, but never exceeded non-bamboo feeding at the latter. Culm pith feeding was only observed at Ambalafary, where it was more common during the dry season. We identify P. simus as a bamboo facultative specialist capable of adjusting its feeding behavior to its environment, indicating greater dietary flexibility than previously documented, which may enable the species to survive in increasingly degraded habitats.

Eyes in the Sky: Assessing the Feasibility of Low-Cost, Ready-to-Use Unmanned Aerial Vehicles to Monitor Primate Populations Directly.

Primates face many climate and land use change threats, making long-term population monitoring critical to prioritizing conservation efforts. Ground-based line transects are typically conducted to estimate and monitor primate populations. However, transects may be costly and logistically challenging. We sought to test whether low-cost (<5,000 USD), ready-to-use unmanned aerial vehicles (UAVs) could effectively monitor primate populations in north-eastern Madagascar. Critically Endangered [A3cd] golden-crowned sifakas (Propithecus tattersalli) are medium-sized, white lemurs whose creamy colour contrasts against defoliated tree canopies, making them an ideal study species for aerial counts. Quad-copter UAV flights over sifaka groups did not elicit antipredator responses. Photographs demonstrated the ability of UAVs to capture viable imagery of sifakas from approximately 20 m above ground level. Unfortunately, crashes resulting from an inability to programme automated flights over hilly forests cut this pilot study short, highlighting several challenges that remain to implementing UAVs in remote field studies. This study demonstrates that while UAVs offer considerable promise in the future of primate research and conservation, high start-up costs and remote field conditions provide challenging obstacles to first time users hoping to use this exciting new technology. Furthermore, we strongly recommend that thermal cameras be used for direct primate counts with UAVs.

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.

Morphological variability or inter-observer bias? A methodological toolkit to improve data quality of multi-researcher datasets for the analysis of morphological variation.

OBJECTIVES: The investigation of morphological variation in animals is widely used in taxonomy, ecology, and evolution. Using large datasets for meta-analyses has dramatically increased, raising concerns about dataset compatibilities and biases introduced by contributions of multiple researchers. MATERIALS AND METHODS: We compiled morphological data on 13 variables for 3073 individual mouse lemurs (Cheirogaleidae, Microcebus spp.) from 25 taxa and 153 different sampling locations, measured by 48 different researchers. We introduced and applied a filtering pipeline and quantified improvements in data quality (Shapiro-Francia statistic, skewness, and excess kurtosis). The filtered dataset was then used to test for genus-wide sexual size dimorphism and the applicability of Rensch's, Allen's, and Bergmann's rules. RESULTS: Our pipeline reduced inter-observer bias (i.e., increased normality of data distributions). Inter-observer reliability of measurements was notably variable, highlighting the need to reduce data collection biases. Although subtle, we found a consistent pattern of sexual size dimorphism across Microcebus, with females being the larger (but not heavier) sex. Sexual size dimorphism was isometric, providing no support for Rensch's rule. Variations in tail length but not in ear size were consistent with the predictions of Allen's rule. Body mass and length followed a pattern contrary to predictions of Bergmann's rule. DISCUSSION: We highlighted the usefulness of large multi-researcher datasets for testing ecological hypotheses after correcting for inter-observer biases. Using genus-wide tests, we outlined generalizable patterns of morphological variability across all mouse lemurs. This new methodological toolkit aims to facilitate future large-scale morphological comparisons for a wide range of taxa and applications.