Topic
Microgale
About: Microgale is a research topic. Over the lifetime, 32 publications have been published within this topic receiving 565 citations.
Papers
TL;DR: A timeframe of tenrec evolution built on the basis of this solid phylogenetic framework showed that morphological specializations of the tenrecs may have been affected by environmental changes caused by climatic and/or subsequent colonization events.
Abstract: Malagasy tenrecs belong to the Afrotherian clade of placental mammals and comprise three subfamilies divided in eight genera (Tenrecinae: Tenrec, Echinops, Setifer and Hemicentetes; Oryzorictinae: Oryzorictes, Limnogale and Microgale; Geogalinae:Geogale). The diversity of their morphology and incomplete taxon sampling made it difficult until now to resolve phylogenies based on either morphology or molecular data for this group. Therefore, in order to delineate the evolutionary history of this family, phylogenetic and dating analyses were performed on a four nuclear genes dataset (ADRA2B, AR, GHR and vWF) including all Malagasy tenrec genera. Moreover, the influence of both taxon sampling and data partitioning on the accuracy of the estimated ages were assessed. Within Afrotheria the vast majority of the nodes received a high support, including the grouping of hyrax with sea cow and the monophyly of both Afroinsectivora (Macroscelidea + Afrosoricida) and Afroinsectiphillia (Tubulidentata + Afroinsectivora). Strongly supported relationships were also recovered among all tenrec genera, allowing us to firmly establish the grouping of Geogale with Oryzorictinae, and to confirm the previously hypothesized nesting of Limnogale within the genus Microgale. The timeline of Malagasy tenrec diversification does not reflect a fast adaptive radiation after the arrival on Madagascar, indicating that morphological specializations have appeared over the whole evolutionary history of the family, and not just in a short period after colonization. In our analysis, age estimates at the root of a clade became older with increased taxon sampling of that clade. Moreover an augmentation of data partitions resulted in older age estimates as well, whereas standard deviations increased when more extreme partition schemes were used. Our results provide as yet the best resolved gene tree comprising all Malagasy tenrec genera, and may lead to a revision of tenrec taxonomy. A timeframe of tenrec evolution built on the basis of this solid phylogenetic framework showed that morphological specializations of the tenrecs may have been affected by environmental changes caused by climatic and/or subsequent colonization events. Analyses including various taxon sampling and data partitions allow us to point out some possible pitfalls that may lead to biased results in molecular dating; however, further analyses are needed to corroborate these observations.
77 citations
TL;DR: The species richness found in the control site, the largest remaining block within the reserve, is comparable to other much more extensive forest blocks at parallel elevations and with similar botanical communities, so it seems that the lipotyphlan community within the controlSite has not experienced notable local extinctions.
Abstract: A small mammal survey of the Lipotyphla (Tenrecidae and Soricidae) was conducted in the montane forest of the Reserve Speciale d'Ambohitantely, Central High Plateau, Madagascar. Species richness of this group was assessed using standardized pit-fall trap techniques in a control site of 1250 ha and four smaller forest fragments (136, 30, 12 and 0.64 ha). The forests of this reserve are highly fragmented, isolated for many decades and about 90 km from the nearest large forest block. On the basis of pit-fall captures, lipotyphlan diversity was highest in the control site with nine species, including eight endemic taxa. The number of species declined progressively with diminishing forest size. The species richness found in the control site, the largest remaining block within the reserve, is comparable to other much more extensive forest blocks at parallel elevations and with similar botanical communities. Thus, it seems that the lipotyphlan community within the control site has not experienced notable local extinctions. The introduced Soricidae, Suncus murinus, has colonized the Ambohitantely forests. However, there is no evidence of competition between this species and members of the family Tenrecidae, particularly Microgale, as has been postulated in the literature.
70 citations
TL;DR: It is concluded that a high level of RMR is advantageous, and possibly essential, for reproduction in the Tenrecidae and may be associated with an improvement in homeothermy.
Abstract: Resting metabolic rate (RMR) and body temperature ($T_{b}$) were measured in the shrew-tenrecs Microgale dobsoni and Microgale talazaci during reproduction. Limited data are also presented for Microgale cowani and Microgale melanorrhachis. Resting metabolic rate and $T_{b}$ fluctuated with ambient temperature ($T_{a}$) so that metabolic rate in nonbreeding animals could not be termed "basal." Resting metabolic rate in nonreproducing adults of all four species at 30°C was higher than levels previously recorded in the Tenrecidae. The smaller species had RMR higher than predicted by the Kleiber curve. During pregnancy and lactation, elevated levels of RMR were attained in M. dobsoni, M. talazaci, and M. cowani, but there was no evidence that the level of RMR attained was influenced by litter size. All three species demonstrated improved thermoregulation during pregnancy. It is concluded that a high level of RMR is advantageous, and possibly essential, for reproduction in the Tenrecidae. Elevated RMR may be a...
48 citations
TL;DR: Phylogenetic analysis of the mitochondrial ND2 gene supports its recognition as a distinct species and suggests a sister relationship with the much more widespread Microgale cowani.
Abstract: A new species of shrew tenrec in the genus Microgale is described from a series of 12 specimens taken on the south-western slopes of the Tsaratanana Massif in northern Madagascar and is named Microgale jobihely. This new species is distinguished from other named members of this endemic genus by a variety of mensural and discrete morphological characters. Phylogenetic analysis of the mitochondrial ND2 gene supports its recognition as a distinct species and suggests a sister relationship with the much more widespread Microgale cowani. Microgale jobihely appears to be the only member of this genus that is a very localized endemic, and a biogeographic scenario is presented to explain this observation. It is currently known from a small area of forest, outside of the protected areas system, that is faced with considerable anthropogenic pressure.
32 citations
TL;DR: Results of stable isotope analysis suggest that in combination the differentiation of microhabitats and trophic niches explain the coexistence of small mammals in this community.
Abstract: Unraveling the mechanisms facilitating species coexistence in communities is a central theme in ecology Species-rich tropical mammal communities provide excellent settings to explore such mechanisms as they often harbor numerous congeneric species with close phylogenetic relationships Explicit tests for the mechanisms that allow syntopic occurrence in these assemblages, however, is often hampered because of the difficulty in obtaining detailed ecological data on the organisms making up the community Using stable nitrogen and carbon ratios of hair samples, we examine whether trophic niche differentiation and microhabitat segregation explain the coexistence of 21 small mammal species at a montane humid forest site in eastern Madagascar Overall, the community was trophically diverse and covered wide isotopic space This diversity was based on: (1) a multi-layered trophic community structure with mainly frugivorous-granivorous rodents (subfamily Nesomyinae) as primary consumers and insectivorous tenrecs (family Tenrecidae) as secondary and tertiary consumers; (2) trophic segregation of rodents and tenrecs with the latter occupying different microhabitats; and (3) a dense and regular packing of species in the community The 12 locally occurring Microgale shrew tenrecs (subfamily Oryzorictinae) showed high trophic redundancy, but were maximally spaced from each other within the trophic space covered by the genus Results of stable isotope analysis suggest that in combination the differentiation of microhabitats and trophic niches explain the coexistence of small mammals in this community Congeneric species appeared to be under more intense competition compared with non-congeneric species and their coexistence can only partly be explained by trophic and microhabitat niche segregation
32 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2020 | 1 |
| 2015 | 1 |
| 2013 | 1 |
| 2010 | 1 |
| 2009 | 1 |