Research experience
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Jan 2007–
Dec 2008Research: Deutsches Primatenzentrum
Deutsches Primatenzentrum · Abteilung Verhaltensökologie & SoziobiologieGermany · Göttingen
Publications (7) View all
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Article: Nuclear versus mitochondrial DNA: evidence for hybridization in colobine monkeys.
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ABSTRACT: Colobine monkeys constitute a diverse group of primates with major radiations in Africa and Asia. However, phylogenetic relationships among genera are under debate, and recent molecular studies with incomplete taxon-sampling revealed discordant gene trees. To solve the evolutionary history of colobine genera and to determine causes for possible gene tree incongruences, we combined presence/absence analysis of mobile elements with autosomal, X chromosomal, Y chromosomal and mitochondrial sequence data from all recognized colobine genera. Gene tree topologies and divergence age estimates derived from different markers were similar, but differed in placing Piliocolobus/Procolobus and langur genera among colobines. Although insufficient data, homoplasy and incomplete lineage sorting might all have contributed to the discordance among gene trees, hybridization is favored as the main cause of the observed discordance. We propose that African colobines are paraphyletic, but might later have experienced female introgression from Piliocolobus/Procolobus into Colobus. In the late Miocene, colobines invaded Eurasia and diversified into several lineages. Among Asian colobines, Semnopithecus diverged first, indicating langur paraphyly. However, unidirectional gene flow from Semnopithecus into Trachypithecus via male introgression followed by nuclear swamping might have occurred until the earliest Pleistocene. Overall, our study provides the most comprehensive view on colobine evolution to date and emphasizes that analyses of various molecular markers, such as mobile elements and sequence data from multiple loci, are crucial to better understand evolutionary relationships and to trace hybridization events. Our results also suggest that sex-specific dispersal patterns, promoted by a respective social organization of the species involved, can result in different hybridization scenarios.BMC Evolutionary Biology 03/2011; 11:77. · 3.52 Impact Factor -
Article: Vertical and horizontal habitats of fruit-feeding butterflies (Lepidoptera) on Siberut, Mentawai
Ecotropica 01/2011; VOLUME 17, 2011, No. 2. · 0.15 Impact Factor -
Article: Mitochondrial evidence for multiple radiations in the evolutionary history of small apes.
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ABSTRACT: Gibbons or small apes inhabit tropical and subtropical rain forests in Southeast Asia and adjacent regions, and are, next to great apes, our closest living relatives. With up to 16 species, gibbons form the most diverse group of living hominoids, but the number of taxa, their phylogenetic relationships and their phylogeography is controversial. To further the discussion of these issues we analyzed the complete mitochondrial cytochrome b gene from 85 individuals representing all gibbon species, including most subspecies. Based on phylogenetic tree reconstructions, several monophyletic clades were detected, corresponding to genera, species and subspecies. A significantly supported branching pattern was obtained for members of the genus Nomascus but not for the genus Hylobates. The phylogenetic relationships among the four genera were also not well resolved. Nevertheless, the new data permitted the estimation of divergence ages for all taxa for the first time and showed that most lineages emerged during four short time periods. In the first, between approximately 6.7 and approximately 8.3 mya, the four gibbon genera diverged from each other. In the second (approximately 3.0 - approximately 3.9 mya) and in the third period (approximately 1.3 - approximately 1.8 mya), Hylobates and Hoolock differentiated. Finally, between approximately 0.5 and approximately 1.1 mya, Hylobates lar diverged into subspecies. In contrast, differentiation of Nomascus into species and subspecies was a continuous and prolonged process lasting from approximately 4.2 until approximately 0.4 mya. Although relationships among gibbon taxa on various levels remain unresolved, the present study provides a more complete view of the evolutionary and biogeographic history of the hylobatid family, and a more solid genetic basis for the taxonomic classification of the surviving taxa. We also show that mtDNA constitutes a useful marker for the accurate identification of individual gibbons, a tool which is urgently required to locate hunting hotspots and select individuals for captive breeding programs. Further studies including nuclear sequence data are necessary to completely understand the phylogeny and phylogeography of gibbons.BMC Evolutionary Biology 03/2010; 10:74. · 3.52 Impact Factor -
Article: Group structure and physical characteristics of Simakobu monkeys (Simias concolor) on the Mentawai Island of Siberut, Indonesia.
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ABSTRACT: We present data on group structure and physical characteristics from free-ranging Simias concolor. Mean group size (n = 3) was 8.7 +/- 1.1 individuals with an average adult male:female sex ratio of 1:3. All individuals were sexed and allocated into three categories (infants, juveniles plus subadults and adults) on the basis of their physical development. Within age categories, head-body lengths ranged from 19.6 to 25, 34 to 44 and 42 to 53 cm. Corresponding body weights ranged from 0.5 to 0.9, 2.35 to 4.4 and 5.2 to 7.85 kg, respectively; on average adult males were 13% larger and 23% heavier than adult females. Results indicate that for S. concolor living in undisturbed habitat (i) group sizes are larger than previously reported and (ii) polygyny is the most likely mating system. Both results support an earlier proposal that group size and social organization in Simakobu monkey are related to the degree of habitat disturbance.Folia Primatologica 05/2009; 80(2):74-82. · 1.00 Impact Factor -
Article: Abundance and community structure of Mentawai primates in the Peleonan forest, north Siberut, Indonesia
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ABSTRACT: The island of Siberut in the Mentawai Archipelago, west of Sumatra, Indonesia, supports four of the five primate species endemic to the Archipelago, all categorized as threatened on the IUCN Red List. As a baseline for future research on the ecology and conservation of Siberut's primates we used a line-transect approach to survey primates in the Peleonan forest, site of the Siberut Conservation Project in northern Siberut. In 104 km of surveys we made a total of 391 observations of primates and estimated density and population sizes for the Project's 10.7 km2 main study site. Overall primate biomass density was estimated to be 697 kg km-2 and abundances, in individuals km-2, were: pig-tailed snub-nosed langur Simias concolor, 53.1; Siberut macaque Macaca siberu, 16.2; Kloss's gibbon Hylobates klossii, 8.9; Mentawai langur Presbytis potenziani, 8.2. These results confirm those from earlier studies that in undisturbed and unhunted primary forests S. concolor is more successful than the sympatrically occurring P. potenziani. Results for all species suggest considerable population sizes on the island and underline its importance for the conservation of Mentawai primates.Oryx 06/2008; 42(03):375 - 379. · 1.83 Impact Factor
