28 research outputs found
Multiple paternity in a viviparous toad with internal fertilisation
Anurans are renowned for a high diversity of reproductive modes, but less than 1% of species exhibit internal fertilisation followed by viviparity. In the live bearing West African Nimba toad (Nimbaphrynoides occidentalis), females produce yolk-poor eggs and internally nourish their young after fertilisation. Birth of fully developed juveniles takes place after nine months. In the present study, we used genetic markers (eight microsatellite loci) to assign the paternity of litters of 12 females comprising on average 9.7 juveniles. In nine out of twelve families (75%) a single sire was sufficient; in three families (25%) more than one sire was necessary to explain the observed genotypes in each family. These findings are backed up with field observations of male resource defence (underground cavities in which mating takes place) as well as coercive mating attempts, suggesting that the observed moderate level of multiple paternity in a species without distinct sperm storage organs is governed by a balance of female mate choice and male reproductive strategies
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Recent colonization and expansion through the Lesser Sundas by seven amphibian and reptile species
The Lesser Sundas Archipelago is comprised of two parallel chains of islands that extend between the Asian continental shelf (Sundaland) and Australo-Papuan continental shelf (Sahul). These islands have served as stepping stones for taxa dispersing between the Asian and Australo-Papuan biogeographical realms. While the oceanic barriers have prevented many species from colonizing the archipelago, a number of terrestrial vertebrate species have colonized the islands either by rafting/swimming or by human introduction. Here, we examine phylogeographic structure within the Lesser Sundas for three snake, two lizard and two frog species that each has a Sunda Shelf origin. These species are suspected to have recently colonized the archipelago, though all have inhabited the Lesser Sundas for over 100 years. We sequenced mtDNA from 231 samples to test whether there is sufficiently deep genetic structure within any of these taxa to reject human-mediated introduction. Additionally, we tested for genetic signatures of population expansion consistent with recent introduction and estimated the ages of Lesser Sundas clades, if any exist. Our results show little to no genetic structure between populations on different islands in five species and moderate structure in two species. Nucleotide diversity is low for all species, and the ages of the most recent common ancestor for species with monophyletic Lesser Sundas lineages date to the Holocene or late Pleistocene. These results support the hypothesis that these species entered the archipelago relatively recently and either naturally colonized or were introduced by humans to most of the larger islands in the archipelago within a short time span
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Leap-frog dispersal and mitochondrial introgression: Phylogenomics and biogeography of Limnonectes fanged frogs in the Lesser Sundas Archipelago of Wallacea
Aim: The Lesser Sunda Islands are situated between the Sunda and Sahul Shelves, with a linear arrangement that has functioned as a two-way filter for taxa dispersing between the Asian and Australo-Papuan biogeographical realms. Distributional patterns of many terrestrial vertebrates suggest a stepping-stone model of island colonization. Here we investigate the timing and sequence of island colonization in Asian-origin fanged frogs from the volcanic Sunda Arc islands with the goal of testing the stepping-stone model of island colonization. Location: The Indonesian islands of Java, Lombok, Sumbawa, Flores and Lembata. Taxon: Limnonectes dammermani and L. kadarsani (Family: Dicroglossidae). Methods: Mitochondrial DNA was sequenced from 153 frogs to identify major lineages and to select samples for an exon-capture experiment. We designed probes to capture sequence data from 974 exonic loci (1,235,981 bp) from 48 frogs including the outgroup species, L. microdiscus. The resulting data were analysed using phylogenetic, population genetic and biogeographical model testing methods. Results: The mtDNA phylogeny finds L. kadarsani paraphyletic with respect to L. dammermani, with a pectinate topology consistent with the stepping-stone model. Phylogenomic analyses of 974 exons recovered the two species as monophyletic sister taxa that diverged ~7.6 Ma with no detectable contemporary gene flow, suggesting introgression of the L. dammermani mitochondrion into L. kadarsani on Lombok resulting from an isolated ancient hybridization event ~4 Ma. Within L. kadarsani, the Lombok lineage diverged first while the Sumbawa and Lembata lineages are nested within a Flores assemblage composed of two parapatrically distributed lineages meeting in central Flores. Biogeographical model comparison found strict stepping-stone dispersal to be less likely than models involving leap-frog dispersal events. Main conclusions: These results suggest that the currently accepted stepping-stone model of island colonization might not best explain the current patterns of diversity in the archipelago. The high degree of genetic structure, large divergence times, and absent or low levels of migration between lineages suggests that L. kadarsani represents five distinct species
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The herpetofauna of the kei islands (Maluku, indonesia): Comprehensive report on new and historical collections, biogeographic patterns, conservation concerns, and an annotated checklist of species from kei kecil, kei besar, Tam, and Kur
In 2011 and 2014, we conducted two expeditions to four islands in the Kei Island group in Maluku Province of eastern Indonesia. We documented and collected 33 species of lizards, snakes, and frogs, and after reviewing historical occurrences in the island group, we accounted for a total of 39 species present in the Kei Islands (26 lizards, 10 snakes, 3 frogs). Here we present a checklist with species accounts and a key to all lizards, snakes, and frogs presently known from the Kei Islands, and discuss potentially erroneous previous records. As presently described, the Kei Islands hold four endemic lizards, though we expect some Kei Island populations of species thought to be widespread will be described as distinct species in the future. We report four species that have not previously been documented from the Kei Islands, including three species of gecko (Lepidodactylus), as well as one frog (Litoria cf. bicolor), which raises the number of known amphibians from two to three. We reassess the biogeography of the Kei Islands in the context of this new survey and suggest that rather than simply being part of a filter zone between the Sunda and Sahul Shelves, a substantial proportion of the fauna of small eastern Indonesian islands such as the Kei Islands shows an allegiance with other oceanic islands in the South Pacific. Finally, we discuss conservation of herpetofauna and overall biodiversity in the Kei Islands
A New Species of Kalophrynus with a Unique Male Humeral Spine from Peninsular Malaysia (Amphibia, Anura, Microhylidae)
A new microhylid, Kalophrynus yongi, is described from the Cameron Highlands of Peninsular Malaysia. Morphologically, the new species differs from all known congeners by having a very stout forelimb with a humeral spine in males. Acoustically, it resembles K. baluensis and K. heterochirus and sharply differs from K. interlineatus, K. pleurostigma, K. palmatissimus, and K. nubicola