Showing papers on "Mantella published in 2007"

Evidence for recent gene flow between north-eastern and south-eastern Madagascan poison frogs from a phylogeography of the Mantella cowani group.

Abstract: The genus Mantella, endemic poison frogs of Madagascar with 16 described species, are known in the field of international pet trade and entered under the CITES control for the last four years. The phylogeny and phylogeography of this genus have been recently subject of study for conservation purposes. Here we report on the studies of the phylogeography of the Mantella cowani group using a fragment of 453 bp of the mitochondrial cytochrome b gene from 195 individuals from 21 localities. This group is represented by five forms: M. cowani, a critically endangered species, a vulnerable species, M. haraldmeieri, and the non-threatened M. baroni, M. aff. baroni, and M. nigricans. The Bayesian phylogenetic and haplotype network analyses revealed the presence of three separated haplotype clades: (1) M. baroni, M. aff. baroni, M. nigricans, and putative hybrids of M. cowani and M. baroni, (2) M. cowani and putative hybrids of M. cowani and M. baroni, and (3) M. haraldmeieri. The putative hybrids were collected from sites where M. cowani and M. baroni live in sympatry. These results suggest (a) a probable hybridization between M. cowani and M. baroni, (b) a lack of genetic differentiation between M. baroni/M. aff. baroni and M. nigricans, (c) evidence of recent gene-flow between the northern (M. nigricans), eastern (M. baroni), and south-eastern (M. aff. baroni) forms of distinct coloration, and (d) the existence of at least three units for conservation in the Mantella cowani group.

Molecular systematics of Malagasy poison frogs in the Mantella betsileo and M. laevigata species groups

Abstract: Malagasy poison frogs of the genus Mantella with its 16 species are currently sub-divided into 5 major groups. Of these, the Mantella betsileo group is traditionally understood as containing four species, Mantella betsileo, M. expectata, M. viridis and M. manery, while the M. laevigata group is considered to be monospecific. A phylogenetic analysis of samples from multiple localities of all species in these two groups, based on sequences of the mitochondrial cytochrome b gene, shows the existence of several well-distinct clades in what is currently considered to be Mantella betsileo: (1) central-western populations from Kirindy, Isalo, and near Antsirabe close to the Betsileo region, to which the name M. betsileo is to be applied, (2) populations of the north-east and north-west, which are closely related to M. viridis and to which the name M. ebenaui is to be applied, and (3) a clade from southernmost Madagascar and from the Tsingy de Bemaraha, which is sister to M. expectata and furthermore includes important intra-clade variation, therefore probably representing one or two undescribed species. Our data also support a large genetic distance of M. manery to all other species and its probable sister-group relationship to the sympatric M. laevigata; M. manery is consequently transferred from the M. betsileo group to the M. laevigata group.

Specialist or generalist? Feeding ecology of the Malagasy poison frog Mantella aurantiaca

Abstract: We studied the diet of a population of free-ranging Mantella aurantiaca, an alkaloid-containing poison frog from Madagascar. As in other poison frogs, this species is thought to sequester alkaloids from arthropod prey. Among prey, mites and ants are known to regularly contain alkaloids and mites appear to be a major source of dietary alkaloids in poison frogs. We predicted that mites and ants would constitute the most important prey item for these frogs. Prey inventories were obtained during the rainy season by stomach flushing 23 adult male and 42 adult female frogs from one population. Males had smaller body sizes than females and ate smaller prey items, but males and females displayed no differences in the number of prey items consumed. The numerical proportion of ants in most specimens was surprisingly low (11% in males and 15% in females), while mites were slightly more frequent (34% in males and 18% in females). Other prey items consumed in large proportions were flies and collembolans. Comparing the total of 5492 arthropod prey items with 1867 arthropods sampled from the frogs' leaf litter habitat, the proportion of prey classes did not significantly differ among the samples, indicating a low degree of prey electivity in this population. Our data suggest that not all poison frogs exhibit a continuous and active preference for feeding on ants and mites, but instead some may consume high proportions of ants due to a high abundance of ants in their environment.

Remarkable records of amphibians and reptiles on Madagascar’s central high plateau

Abstract: We present data on the herpetofauna from the high plateau of Madagascar, based upon recent survey work and analysis of the literature. We visited several sites during a field survey of the critically endangered harlequin mantella, Mantella cowani Boulenger 1882, in the Antoetra and Antratrabe regions. The habitats of the high lands are currently quite altered and only a few spots present a certain degree of forest coverage. At these sites, we discovered several taxa that were little known thus far, not yet recorded for central Madagascar, or possibly still undescribed. M. cowani was found at four sites, although with differences in abundance. Other remarkable species are the frogs Boophis ankaratra Andreone 1993, B. elenae Andreone 1993, and B. rhodoscelis Boulenger 1882, as well as the possibly new species Boophis sp. 2 (aff. boehmei Glaw & Vences 1992), B. sp. 1 (aff. ankaratra), and Gephyromantis sp. (cf. plicifer Boulenger 1882). A further search for M. cowani was also done in the Ambatodadama area (near Antsirabe), where it was formerly known, based upon specimens housed in the Paris Museum. We did not confirm this species at this site, but we found Mantella betsileo (Grandidier 1872): this is the first recent record for this species from a highaltitude locality in central Madagascar, indicating that its type locality (“Pays Betsileo”) is not erroneous, as formerly believed. Most of the species found on the high plateau are typical of eastern rainforests, but evidence from the studied sites confirms that the original zoological assemblages from the high plateau have undergone a marked decline. The giant snake Acrantophis dumerili Jan 1860 was found at Antoetra and near Antsirabe, representing important range extensions. At Antoetra, we also found Pseudoxyrhopus imerinae (Gunther 1890), which is the third known locality for this species. In the collection of the Turin museum, we found a further specimen of this rare snake, collected at Andrangoloaka at the end of the 19th century.

Herpetofaunal assemblages on seven offshore islands of northwestern Madagascar

Abstract: Herpetofaunal communities of the offshore islands of northern Madagascar are diverse and poorly described. We present diversity, abundance and absolute density estimates of reptile species found across seven islands and associated mainland. Our results suggest the presence of a range of species of conservation interest including Zonosaurus tsingy Raselimanana et al. 2000 and Mantella sp. Further surveys and voucher specimens would be necessary to obtain confirmation. We discuss local habitat determinants of presence/absence, temporal fluctuations in abundance, and the role played by island size. Our results indicate potential for niche segregation between different gecko species.

Size at metamorphosis of Boophis occidentalis Glaw & Vences, 1994 in an arid environment of central-southern Madagascar

Abstract: We report the size of tadpoles at metamorphosis of Boophis occidentalis measured upon tadpo - les and froglets collected in a river of the Isalo Massif, central-southern Madagascar The tadpoles ranged from 3-70 mm and newly metamorphosed froglets 22-32 mm snout-vent length, thus reaching about 47- 60 % of the adult size We comment on such a large size at metamorphosis in the light of the adaptation and ecological advantages in arid environment where the species lives, and compare it with that of other sympatric species, such as gottlebei, S brevis, and Mantella expectata