Search publications of the members of the Royal Belgian institute of natural Sciences
-
A molecular diagnostic for identifying central African forest artiodactyls from faecal pellets
-
A morphometric revision of the genus Ophthalmotilapia (Teleostei, Cichlidae) from Lake Tanganyika (East Africa)
-
A simple and versatile respirometer for aquatic animals.
-
African Mole-rats (Bathyergidae): A Complex Radiation in Tropical Soils
-
African rodentia
-
An Assessment Of The Systematics Of The Genus Desmomys Thomas , 1910 (Rodentia : Muridae) Using Mitochondrial DNA sequences
- We analyzed two mitochondrial gene fragments to assess genetic divergence within the genus Desmomys endemic to Ethiopia and its phylogenetic relationships with related genera. The phylogenetic analysis supported the monophyly of the Arvicanthini-Otomyini group and revealed that Stochomys is clearly a member of Arvicanthini. Our study demonstrated that D. harringtoni and D. yaldeni belong to remarkably different mitochondrial lineages, the estimated divergence time between them is 4.10-5.38 Myr. Such early splitting of specialized forest dweller, D. yaldeni, from its sole congener supposes a more ancient formation of some elements of Ethiopian forest rodent fauna than is assumed today.
-
Anthropisation et effets de lisière : impacts sur la diversité des rongeurs dans la Réserve Forestière de Masako (Kisangani, R.D. Congo).
- Anthropogenic effects on rodent richness, diversity, abundance, and relative density were studied in 4 habitats of the Masako Reserve, situated in the northeastern part of the Democratic Republic of the Congo. A primary forest dominated by Gilbertiodendron dewevrei as well as 3 anthropogenic habitats (secondary forest, fallow land, and the edge zone situated between the fallow land and the secondary forest) were sampled for rodents between May 2009 and April 2010. 1275 specimens (24 species and 5 families) were captured to quantify the differences in composition and abundance between the non disturbed habitat and the anthropogenic habitats, and between the edge zone and its adjacent habitats. Results indicated a non uniform rodent distribution across the four habitats. Richness and diversity were high in the edge habitat and low in the primary forest. Every habitat was characterized by a different relative density, of which the highest values were observed for the secondary forest and for the fallow habitat; the lowest value was observed for the primary forest. Edge zone characteristics differed from the adjacent habitats which suggested the existence of edge effects. Abundances differed significantly between habitats except between the secondary forest and the fallow land. The low evenness values observed in all habitats reflected the relative instability of the ecosystems at study. A chi-squared test confirmed the existence of seasonal effects on rodent abundance; the impact of anthropogenic activities on rodent presence was shown in the same way for the anthropogenic habitats but not for the primary forest habitat.
-
Biodiversity and conservation genetics research in Central Africa: new approaches and avenues for international collaboration
-
Biogeographic origin and radiation of Cuban Eleutherodactylus frogs of the auriculatus species group, inferred from mitochondrial and nuclear gene sequences.
- We studied phylogenetic relationships of the Eleutherodactylus auriculatus species group to infer colonization and diversification patterns in this endemic radiation of terrestrial frogs of the genus Eleutherodactylus in the largest of the Greater Antilles, Cuba. An initial screening of genetic diversity based on partial sequences of the 16S rRNA gene in almost 100 individuals of all species of the group and covering the complete known geographic range of their occurrence found most species endemic to small ranges in the eastern Cuban mountains while a single species was widespread over most of Cuba. Our molecular phylogeny, based on 3731 bp of four mitochondrial and one nuclear gene, suggests that most cladogenetic events within the group occurred among clades restricted to the eastern mountains, which acted as refugia and facilitated the diversification in this group. Our results reveal two separate colonization events of Central and Western Cuba and allow inferring the timing of the subsequent diversification events that occurred between 11 and 2 Mya. Because populations previously assigned to E. auriculatus represent four genetically strongly divergent lineages that also differ in their advertisement calls, we propose that E. auriculatus as currently recognized comprises four species. The difficulties in assigning the name auriculatus to any of these four species, and the fact that E. principalis is nested within one of them, stress the need for a thorough taxonomic revision of this group.
-
Complete mitochondrial DNA replacement in a Lake Tanganyika cichlid fish.
- We used nuclear and mitochondrial DNA (mtDNA) sequences from specimens collected throughout Lake Tanganyika to clarify the evolutionary relationship between Lamprologus callipterus and Neolamprologus fasciatus. The nuclear data support the reciprocal monophyly of these two shell-breeding lamprologine cichlids. However, mtDNA sequences show that (i) L. callipterus includes two divergent and geographically disjunct (North-South) mtDNA lineages; and that (ii) N. fasciatus individuals cluster in a lineage sister group to the northern lineage of L. callipterus. The two mtDNA lineages of L. callipterus diverged c. 684 kya to 1.2 Ma, coinciding with a major water level low stand in Lake Tanganyika, which divided the lake into isolated sub-lakes. This suggests that the two mtDNA lineages originated as the result of the separation of L. callipterus populations in different sub-basins. The incongruent phylogenetic position of N. fasciatus can best be explained by an ancient unidirectional introgression from L. callipterus into N. fasciatus. Remarkably, our data indicate that this event resulted in the complete mtDNA replacement in N. fasciatus. Our data suggest that hybridization occurred soon after the divergence of the two L. callipterus mtDNA lineages, probably still during the water level low stand, and that subsequently the invading mtDNA lineage spread throughout the lake.
-
Conservation of the endemic cichlid fishes of Lake Tanganyika Implications from Population level studies based on mtDNA
-
Conservation units based on mitochondrial and nuclear DNA variation among European bullhead populations ( Cottus gobio L ., 1758 ) from Flanders , Belgium
-
Contribution to the systematics and zoogeography of the East-African Acomys spinosissimus Peters 1852 species complex and the description of two new species (Rodentia: Muridae)
- We revised the taxonomic status of the putative Acomys spinosissimus complex based on the comparative study of speci- men collections from Tanzania, Zambia, Zimbabwe, Mozambique, DR Congo and South Africa, by means of analysis of external morphology, craniometry, enzymes, mitochondrial DNA sequences and karyology. Our results confirm that A. spinosissimus represents a complex of species with seemingly non-overlapping distribution ranges. The distribution range of A. spinosissimus appears to be restricted between the Zambesi and Limpopo Rivers, while the reinstated A. selousi (that includes A. transvaalensis) occurs further to the South (i.e. northern limit seemingly just north of the Limpopo River). The investigated populations north of the Zambezi River are morphologically and genetically distinct from A. spinosissimus and A. selousi. Based on this evidence, we described Acomys muzei sp. nov. and Acomys ngurui sp. nov., each one occur- ring separately along one side of the Eastern Arc Mountains. Finally, we lacked sufficient information to describe a third new species from the area north of the Zambesi River.
-
Cytochrome b sequence analysis reveals differential molecular evolution in African mole-rats of the chromosomally hyperdiverse genus Fukomys (Bathyergidae, Rodentia) from the Zambezian region.
- African mole-rats (Bathyergidae, Rodentia) of the (eu)social genus Fukomys are one of the most speciose mammal genera endemic to Sub-Saharan Africa. Fukomys distributed in the Zambezian phytochorion is characterized by extreme chromosomal variation (2n=40-78). We inferred a molecular phylogeny of Zambezian Fukomys to resolve the interrelationships and the evolutionary history of the known chromosomal races. We sequenced the entire cytochrome b gene (1140bp) for a total of 66 specimens representing 18 karyotypical races from Zambia. An additional 31 sequences were retrieved from GenBank including data on all other chromosomal races. The haplotypes belonging to a small chromosomal race from Salujinga cluster with the Fukomys mechowii (Giant mole-rat) haplotypes. Differential degrees of chromosomal variation are observed among the major mole-rat clades, which is most pertinent when comparing the central Zambezian Fukomys micklemi and the northern Zambezian Fukomys whytei clades. The karyotypically hyper-diverse (12 known chromosomal races) Fukomys micklemi clade shows low levels of cytochrome b sequence divergence. Within the F. whytei clade we find a more conservative pattern of chromosomal diversification (three known chromosomal races) while the levels of sequence divergence are much higher then in the F. micklemi clade. Our results suggest that chromosomal changes may drive phyletic divergence and, eventually, speciation. The observed cladogenetic events during the Plio-Pleistocene within the F. mechowii, F. whytei, F. damarensis and F. micklemi clades appear to coincide with climatically mediated speciation bursts in other savannah dwelling mammals, including hominids. Based on the molecular data presented, combined with morphological and chromosomal data, the taxonomic implication seems to be that Fukomys may contain several (undescribed) cryptic species.
-
Dealing with food and eggs in mouthbrooding cichlids: structural and functional trade-offs in fitness related traits.
- As in any vertebrate, heads of fishes are densely packed with functions. These functions often impose conflicting mechanical demands resulting in trade-offs in the species-specific phenotype. When phenotypical traits are linked to gender-specific parental behavior, we expect sexual differences in these trade-offs. This study aims to use mouthbrooding cichlids as an example to test hypotheses on evolutionary trade-offs between intricately linked traits that affect different aspects of fitness. We focused on the oral apparatus, which is not only equipped with features used to feed and breathe, but is also used for the incubation of eggs. We used this approach to study mouthbrooding as part of an integrated functional system with diverging performance requirements and to explore gender-specific selective environments within a species.
-
Discovery of a new duiker species (Bovidae: Cephalophinae) from the Dahomey Gap, West Africa
- Among the two most widely distributed duiker species, Philantomba monticola (Thunberg, 1789) and Philantomba maxwelli (C.H. Smith, 1827), the latter shows geographic variation in pelage color and body size. This issue was not investigated in detail so far, especially in the eastern region of its distribution area, notably due to the lack of material from the Dahomey Gap. We undertook a species-level revision of Philantomba in West Africa, notably including a series of specimens collected in Togo, Benin and Nigeria. Using morphological measurements (craniometry) and genetic data (two mitochondrial and three nuclear markers), we describe a new duiker species occurring in the Dahomey Gap (Togo, Benin) and the Niger delta, Philantomba walteri sp. nov. This discovery highlights the importance of the Dahomey Gap for the evolutionary history of the West African forest faunas. It also has conservation implications given that the new species is one of the main targets of the local bushmeat trade.
-
Distinct population structure in a phenotypically homogeneous rock-dwelling cichlid fish from Lake Tanganyika.
- Several lineages of cichlid fishes in the East African Great Lakes display stunning levels of morphological diversification. The rapid evolution of rock-dwelling polygynous mouthbrooders in Lake Malawi, for example, was in part ascribed to their allopatric distribution on disjunct stretches of rocky coast, where even short habitat discontinuities reduce gene flow effectively. However, as seen in other cichlids, ecological barriers do not always prevent gene flow, whereas genetic structure can develop along continuous habitat, and morphological diversification does not necessarily accompany genetic differentiation. The present study investigates the population structure of Variabilichromis moorii, a monogamous substrate-brooding lamprologine of rocky coasts in Lake Tanganyika, which occurs over about 1000 km of shoreline almost without phenotypic variation. Phylogeographic analyses of mitochondrial DNA sequences indicated that dispersal is infrequent and generally occurs between adjacent locations only. Exceptions to this pattern are closely related haplotypes from certain locations on opposite lakeshores, a phenomenon which has been observed in other species and is thought to reflect lake crossing along an underwater ridge in times of low water level. Genetic population differentiation, estimated from mitochondrial DNA and microsatellite data in six adjacent populations, was equally high across localities separated by sandy shores and along uninterrupted stretches of rocky shore. Our results suggest that ecological barriers are not required to induce philopatric behavior in Variabilichromis, and that morphological stasis persists in the face of high levels of neutral genetic differentiation.
-
Divergent and reticulate processes in evolution of Ethiopian Lophuromys flavopunctatus species complex : evidence from mitochondrial and nuclear DNA differentiation patterns
- Molecular study of mitochondrial and nuclear genes and cytogenetic analysis were performed to examine possible patterns of speciation in the diverse Lophuromys flavopunctatus species complex of Ethiopia. Phylogenetic analysis of mtDNA data resulted in an unresolved bush of ten deeply diverged haplotype groups corresponding to potential species either well supported by various types of character or ‘cryptic’. The cytogenetic analysis showed represen- tatives of five of these mtDNA lineages to share an identical karyotype (2n = 70, NFa = 84), that has not been found previously in Ethiopia. One of them, L. cf. sikapusi, being a member of the L. flavopunctatus species complex, dem- onstrates remarkable morphological similarity to representatives of another species complex, L. sikapusi s.l., which might be considered as a result of convergent evolution in analogous environments. Analysis of RAPD data suggests that at least two mtDNA types might have been subject to interspecific transfer due to hybridization. In the case of two sympatric haplotypes of L. brunneus we may assume that the contemporary pattern of variation between them can be explained by relatively recent hybridization with another distinct species, L. flavopunctatus. The formation of two groups belonging to distinct mitochondrial lineages within northern populations could be associated with more complex processes including ancient hybridization.
-
Diversity, dynamics and reproduction in a community of small mammals in Upper Guinea , with emphasis on pygmy mice ecology
-
DNA Barcoding Amphibians and Reptiles
- Only a few major research programs are currently targeting COI barcoding of amphibians and reptiles (including chelonians and crocodiles), two major groups of tetrapods. Amphibian and reptile species are typically old, strongly divergent, and contain deep conspecifi c lineages which might lead to problems in species assignment with incomplete reference databases. As far as known, there is no single pair of COI primers that will guarantee a suffi cient rate of success across all amphibian and reptile taxa, or within major subclades of amphibians and reptiles, which means that the PCR amplifi cation strategy needs to be adjusted depending on the specifi c research question. In general, many more amphibian and reptile taxa have been sequenced for 16S rDNA, which for some purposes may be a suitable complementary marker, at least until a more comprehensive COI reference database becomes available. DNA barcoding has successfully been used to identify amphibian larval stages (tadpoles) in species-rich tropical assemblages. Tissue sampling, DNA extraction, and amplifi cation of COI is straightforward in amphibians and reptiles. Single primer pairs are likely to have a failure rate between 5 and 50\% if taxa of a wide taxonomic range are targeted; in such cases the use of primer cocktails or subsequent hierarchical usage of different primer pairs is necessary. If the target group is taxonomically limited, many studies have followed a strategy of designing specifi c primers which then allow an easy and reliable amplifi cation of all samples.
