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Map of Madagascar with the ranges of C. sp. nov. 2 and other species in the C. crossleyi group: C. andysabini, C. crossleyi, C. lavasoensis, and CCS2. Map also includes lineages of other Cheirogaleus species groups that are partially sympatric, C. sibreei and CCS5. Additionally, C. major is included with the newly reported population at Sahafina. Photographs are provided to show the distinct phenotypic differences between sympatric lineages.
Source publication
A new species in the genus Cheirogaleus is described from Ranomafana and Andringitra national parks, Madagascar. Ranomafana National Park is a rainforest situated in a montane region, and Andringitra National Park is comprised of grassland, lowland and highland forests displaying great altitudinal variation. Both parks are known to harbor wide spec...
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Context 1
... than previously known for C. crossleyi. Additional sites are being identified not just for C. crossleyi, but other Cheirogaleus lineages. A population of C. major was recently identified at Sahafina and confirmed with mitochondrial DNA (D-loop) sequenced from fecal samples. The presence of this population is being reported here for the first time (Fig. ...
Context 2
... close populations of Cheirogaleus, C. andysabini, C. lavasoensis and C. crossleyi. Geographic isolation should not be the sole consideration for diagnosing a new species, but should be considered as one piece of evidence alongside other factors. In this case other factors include genetic divergence, size, pelage variation, and habitat elevation ( Fig. 3; Table 2; Table ...
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Knowledge on status of peripheral plant populations is important for understanding of species’ adaptation and evolution within their ranges. There is a lack of data on the status of Silaum silaus (Apiaceae) populations at the periphery of its native range. One of the most northern native S. silaus populations is situated in the Republic of Mordovia...
Citations
... This is because they are much smaller than their diurnal relatives (Mittermeier et al., 2008) and their small bodies make it difficult for them to cross the large open spaces between isolated forest fragments (Guschanski et al., 2007;Olivieri et al., 2008;but see Steffens et al., 2021). Further, these families have undergone heavy taxonomic expansion in recent years (Yoder et al., 2000;Louis et al., 2006;Groves, 2016;McLain et al., 2017) and many newly described species have restricted geographic distributions . Due to their vulnerability, forest fragmentation may have detrimental effects on the distribution and population density of cheirogaleids and lepilemurids (Lehman, Rajaonson, & Day, 2006b, 2006cRandrianambinina et al., 2010;Ibouroi, Schwitzer, & Rabarivola, 2013;Steffens & Lehman, 2016), and fragmentation has also been linked to genetic bottlenecks in these populations (Craul et al., 2009). ...
The clearing and fragmentation of tropical forests is the single biggest threat to primate populations who depend on this habitat for survival. In contrast to primates that live in continuous, undisturbed forests, primate communities of fragmented forests need to adapt to decreased food availability and increased inter-and intraspecific competition typical of these degraded and anthropogenically disturbed habitats. Some primate species are highly sensitive to habitat fragmentation, whilst other species can adapt and even thrive in fragmented and degraded forests. Here, we assessed how forest fragmentation and associated edge effects impact the population density of four species of nocturnal lemur in the Sahamalaza-Iles Radama National Park, North West Madagascar. We conducted 118 transect walks over a 3-year period covering a total distance of 107 km to collect encounter rate (N/km) and population density (N/Ha) data for each species, which we then compared between the edge and core areas of a continuous forest and a fragmented forest. Our results were highly species-specific, with the population densities of two species (Lepilemur sahamalaza and Microcebus sambiranensis) increasing in edge and fragmented habitat, whilst we observed the opposite for Cheirogaleus medius. Mirza zaza density appeared consistent between the continuous and fragmented forest and in both edge and core areas. We also found evidence of species-specific population density relationships with fragment size, core area and fragment shape; however, further work is needed to support these findings. This study demonstrates that some nocturnal lemurs can adapt to degraded habitats and thrive within fragmented forests, whilst other species are less capable of doing so.
... The dwarf lemurs (genus Cheirogaleus) are a group of nine, small, omnivorous, primate species from Madagascar (Groves, 2016;McLain et al., 2017) and are the sole group of primates that enter obligate hibernation (Dausmann, 2008;Dausmann & Blanco, 2016;Wright & Martin, 1995). To do this, Cheirogaleus spp. ...
Primate encounter rates often vary throughout the year due to seasonal differences in activity, ecology, and behaviour. One notably extreme behaviour is continuous hibernation. Although a rare adaptation in primates, the dwarf lemurs of Madagascar (genus Cheirogaleus) enter obligate hibernation each year during the dry season, after spending the wet season consuming high-energy foods. Whilst seasonal changes in activity in some Cheirogaleus populations are well-known, many species remain little-studied, and there is no specific information on their encounter rates, nor when they enter and emerge from hibernation. This uncertainty critically affects reliable calculation of population density estimates for these highly threatened lemurs. In this study, we assessed how encounter rates of the fat-tailed dwarf lemur (C. medius) vary seasonally in the transitional forests of the Sahamalaza-Iles Radama National Park, northwest Madagascar, during a 4-year period. We established a system of line transects (N = 60) throughout our study area, on which we conducted distance sampling of C. medius. We then used our distance sampling data to calculate encounter rate and population density data. We found encounter rates of C. medius to be significantly higher during the wet season compared with the dry season. Furthermore, encounter rates of C. medius were particularly low from May–August. These results provide some evidence to suggest the time period that C. medius hibernate in Sahamalaza-Iles Radama National Park. These findings underpin the importance of careful study design when surveying threatened species with seasonal differences in activity, such as those that hibernate. This study also demonstrates the importance of species-specific behavioural data for accurate population density assessment, which is required to inform conservation action.
... The Cheirogaleidae are a diverse family of lemurs, made up of five genera, containing a total of 41 small-bodied, nocturnal, and largely solitary species (Hotaling et al., 2016;McLain et al., 2017;Mittermeier et al., 2008). Cheirogaleid lemurs are widespread throughout all of Madagascar's forest types and they are present within both pristine and disturbed habitat (Mittermeier et al., 2010). ...
Aim: Global animal populations are in decline due to destruction and degradation
of their natural habitat. Understanding the factors that determine the distribution
and density of threatened animal populations is therefore now a crucial component
of their study and conservation. The Cheirogaleidae are a diverse family of small-bodied,
nocturnal lemurs that are widespread throughout the forests of Madagascar.
However, many cheirogaleid lemurs are now highly threatened with extinction and
the environmental factors that determine their distribution and population density
are still little known. Here, I investigated the environmental drivers of Cheirogaleidae
population density at genus level.
Location: Various forest sites across Madagascar.
Methods: I investigated how six environmental variables affect Cheirogaleidae population
density at the genus level via random-effect meta-analyses. I then used a generalized
linear mixed-effects model to identify the primary predictors of Cheirogaleidae
population density. Finally, I investigated how the population density of this family
of lemurs varies between protected and unprotected areas of Madagascar via a GLM
analysis.
Results: My results indicate that the relationships between the tested environmental
factors and population density are genus-specific among the Cheirogaleidae. Rather remarkably, the density of Microcebus appears to have a profoundly positive relationship
with anthropogenic disturbance and a negative relationship with forest cover, a
finding that is also reflected by larger population densities within unprotected areas
in comparison with localities within Madagascar's protected area network.
Main Conclusions: The results of this study are highly encouraging for the conservation
of the Cheirogaleidae and highlight the remarkable resilience of these lemurs to
habitat degradation and anthropogenic activity. However, this study also outlines the
dearth of knowledge that we have for many species, and why these data are urgently
needed to understand the biogeography and ecology of threatened animal populations
and implement successful conservation.
... Our indirect evidence suggests that in Vohimana, Cheirogaleus apparently hibernates earlier (early May) and emerges earlier (early August) than in Tsinjoarivo forest (males hibernate from late May to mid-September, females from mid-late June to mid-September; Blanco et al., 2010) and in Ranomafana National Park (from May to late September; Wright and Martin, 1995). Recent molecular analysis revealed the presence of furry-eared dwarf lemurs in most forests sites around Vohimana (Andasibe, Mantadia, Torotorofotsy, Maromizaha;McLain et al., 2017), but as in the nearby Torotorofotsy area the presence of both greater dwarf lemurs and hairy-eared dwarf lemurs was reported based on field surveys (Rakotondratsimba et al., 2013), further morphological and genetic analyses may help to confirm the taxonomic identity of the observed Cheirogaleus species in Vohimana. The presence of the elusive aye-aye was only indirectly detected through the observation of bite marks. ...
... Our indirect evidence suggests that in Vohimana, Cheirogaleus apparently hibernates earlier (early May) and emerges earlier (early August) than in Tsinjoarivo forest (males hibernate from late May to mid-September, females from mid-late June to mid-September; Blanco et al., 2010) and in Ranomafana National Park (from May to late September; Wright and Martin, 1995). Recent molecular analysis revealed the presence of furry-eared dwarf lemurs in most forests sites around Vohimana (Andasibe, Mantadia, Torotorofotsy, Maromizaha;McLain et al., 2017), but as in the nearby Torotorofotsy area the presence of both greater dwarf lemurs and hairy-eared dwarf lemurs was reported based on field surveys (Rakotondratsimba et al., 2013), further morphological and genetic analyses may help to confirm the taxonomic identity of the observed Cheirogaleus species in Vohimana. The presence of the elusive aye-aye was only indirectly detected through the observation of bite marks. ...
... Our indirect evidence suggests that in Vohimana, Cheirogaleus apparently hibernates earlier (early May) and emerges earlier (early August) than in Tsinjoarivo forest (males hibernate from late May to mid-September, females from mid-late June to mid-September; Blanco et al., 2010) and in Ranomafana National Park (from May to late September; Wright and Martin, 1995). Recent molecular analysis revealed the presence of furry-eared dwarf lemurs in most forests sites around Vohimana (Andasibe, Mantadia, Torotorofotsy, Maromizaha;McLain et al., 2017), but as in the nearby Torotorofotsy area the presence of both greater dwarf lemurs and hairy-eared dwarf lemurs was reported based on field surveys (Rakotondratsimba et al., 2013), further morphological and genetic analyses may help to confirm the taxonomic identity of the observed Cheirogaleus species in Vohimana. The presence of the elusive aye-aye was only indirectly detected through the observation of bite marks. ...
The Vohimana Reserve is located in the heart of the Ankeniheny-Zahamena corridor, one of Madagascar's conservation priorities, and hosts a mid-altitude rainforest. The forest has long faced strong anthropogenic disturbances, such as slash-and-burn agriculture, logging, and poaching. Prior to this study no long-term study on the lemur community in Vohimana had been conducted and no updated information was available. We aimed to provide a lemur inventory and a description of threats that could be used by forest managers in order to inform and optimize future conservation plans. Between April and December 2018, we surveyed the forest using line-transect distance sampling. Our results show that Vohimana is home to 11 lemur species , including two critically endangered species (Indri indri and Propithecus diadema).We found no evidence of the presence of the black-and-white ruffed lemur (Varecia variegata), which was once reported to inhabit the forest. The possible disappearance of this species, the low frequency of Lemuridae species observations, and the observation of snares, selective logging, and charcoal production suggest actions and long-term monitoring are urgently needed in order to protect this fragile but strategic ecosystem.
... Here, we focus on Madagascar's dwarf lemurs (genus Cheirogaleus). The genus has undergone substantial taxonomic revisions in recent years (Rumpler et al. 1994;Pastorini et al. 2001;Groeneveld et al. 2009Groeneveld et al. , 2010Groeneveld et al. , 2011Lei et al. 2014Lei et al. , 2015Frasier et al. 2016;Mclain et al. 2017), though four species complexes have remained generally well resolved: Cheirogaleus sibreei, C. medius, C. crossleyi, and C. major. All dwarf lemurs are small (between 150 and 450 g), nocturnal, obligate hibernating primates. ...
Our study illustrates the power of selective sampling and genomic analysis for identifying populations/species in need of conservation, given that analyses of whole genomes allows us to identify historical events detectable in the genomes of extant individuals. We conclude from our analyses that the Cheirogaleus sp. cf. medius population warrants further investigation, both taxonomically, given its disjunct distribution, and as a species of conservation concern. All four taxa show temporal changes in ancestral Ne over the last 2 million years with an overall decrease in Ne in recent years (50 k years). While species may recover from some fluctuation in population size, large crashes leave long-term traces in the genome that can be detrimental to long-term survival of populations (Palkopoulou et al. 2015). We demonstrate that for Cheirogaleus, such events can be potentially disadvantageous, such as low heterozygosity from population declines, as seen in C. sp. cf. medius. However, the significant enrichment of several categories of genes in introgressed regions of the genome, shown by the GO analysis, demonstrates for the first time a potential source of novel variation in Cheirogaleus. Hybridization is a pervasive evolutionary force and can drive adaptive differentiation between populations (Runemark et al. 2018). We show that ancient admixture may have been a possible mechanism for adaptive phenotypic evolution in these species of concern.
... Here, we focus on Madagascar's dwarf lemurs (genus Cheirogaleus). The genus has undergone substantial taxonomic revisions in recent years (Rumpler et al. 1994;Pastorini et al. 2001;Groeneveld et al. 2009Groeneveld et al. , 2010Groeneveld et al. , 2011Lei et al. 2014Lei et al. , 2015Frasier et al. 2016;Mclain et al. 2017), though four species complexes have remained generally well resolved: Cheirogaleus sibreei, C. medius, C. crossleyi, and C. major. All dwarf lemurs are small (between 150 and 450 g), nocturnal, obligate hibernating primates. ...
Madagascar's biodiversity is notoriously threatened by deforestation and climate change. Many of these organisms are rare, cryptic, and severely threatened, making population-level sampling unrealistic. Such is the case with Madagascar's dwarf lemurs (genus Cheirogaleus), the only obligate hibernator within the primates. We here apply comparative genomic approaches to generate the first genome-wide estimates of genetic diversity within species of Cheirogaleus. We generate a reference genome for the fat-tailed dwarf lemur, Cheirogaleus medius, and use this resource to facilitate analyses of high-coverage (~30x) genomes for wild-caught individuals representing four dwarf lemur species: Cheirogaleus sp. cf. medius, C. major, C. crossleyi and C. sibreei. This study therefore represents the largest contribution to date of novel genomic resources for Madagascar's lemurs. We show that phylogenetic relationships among the four lineages of Cheirogaleus demonstrate broad-scale concordance across the genome, and yet we detect a number of discordant genomic regions. Using the size distribution of introgressed regions, we estimate that admixture, and subsequent introgression, occurred between species an average of 4.1 Mya. Introgressed regions contain genes associated with hibernation, though most significantly, show over-represented gene ontology categories relating to transcription. Finally, we estimate levels of heterozygosity and find particularly low levels in an individual sampled from an isolated population of C. medius that we refer to as C. sp. cf. medius. Our study highlights the power of comparative genomic analysis for identifying species and populations of conservation concern, as well as for illuminating possible mechanisms of adaptive phenotypic evolution - in this case, hibernation.
... Based on multiple taxonomic references, the latest book All the World's Primates (AWP) identifies 505 primate species. 1 Since its publication in 2016, more species have been described. [2][3][4][5][6][7] The latter group even includes a newly recognized species of great ape, Pongo tapanuliensis. 2 New species descriptions often reignite a debate that has long plagued biological sciences: "What is a species?" How much distinctiveness is enough to warrant a new name or to elevate a subspecies to species rank? ...
The varied answers to the question “What is a species?” provoke more than lively debates in academic circles. They pose practical problems for law enforcement. Commercial wildlife trade threatens many primate species and is regulated through such laws and international agreements as the U.S. Endangered Species Act and the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Enforcing legislation relies on the ability to identify when violations occur. Species‐defining characters may not be preserved in wildlife trade items. For example, pelage patterns and behavioral characters (e.g., vocalizations) are absent from skulls. Accordingly, identifying victims of illegal trade can be difficult, which hinders enforcement. Moreover, identifying new species and “splitting” of currently recognized species can result in enforcement lags and regulatory loopholes. Although such negative consequences should not hinder scientific advancement, we suggest that they be considered by primate taxonomists and provide recommendations to prevent unintended conservation consequences.
Ecological niches are the environmental conditions under which an organism can maintain viable populations. A detailed understanding of an organisms’ ecological niche can provide information on its taxonomy and biogeography, and ecological niche modelling allows researchers to investigate how closely-related species are able to coexist. Ecological niche models also enable conservationists to determine species’ habitat requirements, map distributions, and assess threats. We used this approach to investigate the conservation biogeography of the dwarf lemurs (genus Cheirogaleus), a group of cryptic, nocturnal primates endemic to Madagascar. Using climatic and vegetation-related variables, we constructed ecological niche models for three species to investigate niche overlap among taxa. We also constructed maps of the availability of forest habitat, and we assessed anthropogenic risk and protection. Our ecological niche models and background tests indicated that each of the three analysed Cheirogaleus species occupies distinct environmental space. The area of suitable habitat (realized niche) varied interspecifically (28,889–41,934 km²). This also was mirrored by variation in the percentage of each species’ realized niche within protected areas (20,065–25,266 km²) and near anthropogenic features (5,744–16,999 km²). Our results support the 2020 taxonomy of the dwarf lemurs recognised by the IUCN Red List and provides information on their biogeography. Furthermore, our ecological niche models have highlighted that the habitat of some dwarf lemur species, such as C. crossleyi, are more threatened than other species, such as C. medius and C. major, and these species require urgent conservation attention.
