Time filter

Source Type

Saint-Germain-du-Bois, France

Vargas-Ramirez M.,Museum of Zoology Museum fur Tierkunde | Maran J.,LAssociation du Refuge des Tortues | Fritz U.,Museum of Zoology Museum fur Tierkunde
Organisms Diversity and Evolution | Year: 2010

Using sequence data of the mitochondrial cytochrome b gene, we investigated phylogeographic differentiation of the Amazonian tortoise species Chelonoidis carbonaria and C. denticulata. While C. carbonaria is generally restricted to savannah habitats and adjacent forests, C. denticulata is associated with wet tropical and subtropical forests. Our study suggests a correlation between distinct habitat preferences and phylogeography of the two species. In Maximum Parsimony, Maximum Likelihood and Bayesian analyses, haplotypes of C. carbonaria cluster in several distinct clades reflecting the species' patchy distribution in savannah habitats. By contrast, haplotypes of C. denticulata are only weakly differentiated; a finding also confirmed by parsimony network analysis. This suggests that the contiguous Amazonian rainforest allows gene flow between populations of the forest-dwelling C. denticulata throughout the range, but significantly impedes gene flow in C. carbonaria. The phylogeographic structure and extant distribution pattern of C. carbonaria is supportive of former Amazonian rainforest fragmentation, enabling the dispersal of savannah species. Based on fossil calibration, we dated divergence times for the C. carbonaria clades using a relaxed molecular clock, resulting in average estimates ranging from 4.0-2.2 mya. This implies that the onset of rainforest fragmentation could predate the Pleistocene considerably. Furthermore, our findings call for further research on geographic and taxonomie variation in C. carbonaria and for a reassessment of the conservation status of the distinct genetic units. © Gesellschaft für Biologische Systematik 2010. Source

Fritz U.,Museum of Zoology | Branch W.R.,Port Elizabeth Museum | Branch W.R.,Nelson Mandela Metropolitan University | Hofmeyr M.D.,University of the Western Cape | And 8 more authors.
Zoologica Scripta | Year: 2011

With 18 currently recognised species, Pelusios is one of the most speciose chelonian genera worldwide, even though the taxonomy of some species is contentious. Recent investigations suggested that the closely related, but morphologically distinct genus Pelomedusa is paraphyletic with respect to Pelusios, and that Pelomedusa consists of nine deeply divergent lineages. Using three mitochondrial and three nuclear DNA fragments (2054bp mtDNA, 2025bp nDNA), we examined for the first time the phylogeny of Pelusios by molecular means. Our analyses included all Pelusios species, except the probably extinct P.seychellensis, as well as the nine Pelomedusa lineages. The results showed that Pelusios and Pelomedusa are reciprocally monophyletic. Limited sampling of Pelusios species and homoplasy introduced by remote outgroups most likely explain the paraphyly of Pelomedusa in previous studies. The distinctiveness of most Pelusios species was confirmed, but none of the currently recognised species groups within Pelusios was monophyletic. In Pelusios rhodesianus and P.sinuatus distinct genetic lineages were discovered, suggestive of cryptic taxa. In contrast, the recognition of the weakly differentiated P.castaneus and P.chapini as full species is doubtful, as is the validity of the Malagasy and Seychellois subspecies of P.castanoides. GenBank sequences of P.williamsi were nested within P.castaneus, but the morphological distinctiveness of the two species makes it likely that the GenBank sequences (derived from a turtle from the pet trade) are misidentified. Divergence among the distinct genetic lineages of Pelomedusa equals or exceeds the differences among Pelusios species, supporting the view that Pelomedusa is a species complex. © 2010 The Authors. Zoologica Scripta © 2010 The Norwegian Academy of Science and Letters. Source

Vargas-Ramirez M.,Museum of Zoology Museum fur Tierkunde | Vences M.,TU Braunschweig | Branch W.R.,Port Elizabeth Museum | Branch W.R.,University of Witwatersrand | And 9 more authors.
Molecular Phylogenetics and Evolution | Year: 2010

We investigated the phylogeographic differentiation of the widely distributed African helmeted terrapin Pelomedusa subrufa based on 1503 base pairs of mitochondrial DNA (partial cyt b and ND4 genes with adjacent tRNAs) and 1937 bp of nuclear DNA (partial Rag1, Rag2, R35 genes). Congruent among different analyses, nine strongly divergent mitochondrial clades were found, representing three major geographical groupings: (1) A northern group which includes clades I from Cameroon, II from Ghana and Ivory Coast, III from Benin, Burkina Faso and Niger, IV from the Central African Republic, and V from Kenya, (2) a northeastern group consisting of clades VI from Somalia, and VII from Saudi Arabia and Yemen, and (3) a southern group comprising clade VIII from Botswana, the Democratic Republic of Congo, Madagascar and Malawi, and clade IX from South Africa. Malagasy and continental African populations were not clearly differentiated, indicating very recent arrival or introduction of Pelomedusa in Madagascar. The southern group was in some phylogenetic analyses sister to Pelusios, rendering Pelomedusa paraphyletic with respect to that genus. However, using partitioned Bayesian analyses and sequence data of the three nuclear genes, Pelomedusa was monophyletic, suggesting that its mitochondrial paraphyly is due to either ancient introgressive hybridization or phylogenetic noise. Otherwise, nuclear sequence data recovered a lower level of divergence, but corroborated the general differentiation pattern of Pelomedusa as revealed by mtDNA. This, and the depth of the divergences between clades, indicates ancient differentiation. The divergences observed fall within, and in part exceed considerably, the differentiation typically occurring among chelonian species. To test whether Pelomedusa is best considered a single species composed of deep genealogical lineages, or a complex of up to nine distinct species, we suggest a future taxonomic revision that should (1) extend the geographical sampling of molecular data, specifically focusing on contact zones and the possible sympatric occurrence of lineages without admixture, and (2) evaluate the morphology of the various genealogical lineages using the type specimens or topotypical material of the numerous junior synonyms of P. subrufa. © 2010 Elsevier Inc. Source

Kindler C.,Museum of Zoology Museum fur Tierkunde | Branch W.R.,Port Elizabeth Museum | Branch W.R.,Nelson Mandela Metropolitan University | Hofmeyr M.D.,University of the Western Cape | And 7 more authors.
Journal of Zoological Systematics and Evolutionary Research | Year: 2012

We examine the phylogeography, phylogeny and taxonomy of hinge-back tortoises using a comprehensive sampling of all currently recognized Kinixys species and subspecies and sequence data of three mitochondrial DNA fragments (2273bp: 12S rRNA, ND4+adjacent DNA coding for tRNAs, cytb) and three nuclear loci (2569bp: C-mos, ODC, R35). Combined and individual analyses of the two data sets using Bayesian and Maximum Likelihood methods suggest that the savannah species of Kinixys are paraphyletic with respect to the rainforest species K. homeana and K. erosa, and that the rainforest species may be derived from a savannah-living ancestor. The previously recognized savannah species K. belliana was a conglomerate of three deeply divergent clades that we treat here as distinct species. We restrict the name K. belliana (Gray, 1830) to hinge-back tortoises ranging from Angola to Burundi, while five-clawed hinge-back tortoises from the northernmost part of the formerly recognized range of K. belliana, together with four-clawed tortoises from West Africa, are assigned to the species K. nogueyi (Lataste, 1886). These two species are allied to K. spekii, whereas Southeast African and Malagasy hinge-back tortoises formerly lumped together with K. belliana represent the distinct species K. zombensis Hewitt, 1931, which is sister to K. lobatsiana. The latter two species together constitute the sister group of the rainforest species K. homeana and K. erosa. Mitochondrial data suggest that K. natalensis has a basal phylogenetic position in a clade embracing K. belliana sensu stricto, K. nogueyi and K. spekii, while nuclear data and the two data sets combined favour a sister group relationship of K. natalensis to all other hinge-back tortoises. Phylogeographic structure is present in all wide-ranging species and correlates in K. homeana and K. erosa with the Dahomey Gap and former rainforest refugia. The Malagasy population of K. zombensis is weakly differentiated from its South African conspecifics and further sampling is needed to determine whether there is support for the subspecific distinctness of Malagasy tortoises. © 2012 Blackwell Verlag GmbH. Source

Fritz U.,Museum of Zoology Museum fur Tierkunde | Stuckas H.,Museum of Zoology Museum fur Tierkunde | Vargas-Ramirez M.,Museum of Zoology Museum fur Tierkunde | Hundsdorfer A.K.,Museum of Zoology Museum fur Tierkunde | And 2 more authors.
Journal of Zoological Systematics and Evolutionary Research | Year: 2012

We analyse phylogeny, systematics and biogeography of slider turtles (Trachemys spp.) using sequence data of four mitochondrial genes (3242bp) and five nuclear loci (3396bp) of most South American and southern Central American taxa and representatives of northern Central American, West Indian and North American slider species (16 species and subspecies) and allied North American species (genera Chrysemys, Deirochelys, Graptemys, Malaclemys, Pseudemys). By applying maximum likelihood, relaxed molecular clock and ancestral range analyses, we provide evidence for two successive colonizations of South America by slider turtles. In addition, we show that the current species delineation of Central and South American slider turtles is incorrect. Our data suggest that Trachemys grayi is a distinct polytypic species that embraces, besides the nominotypical subspecies, T. g. emolli and T. g. panamensis. Trachemys ornata is also polytypic with the subspecies T. o. ornata, T. o. callirostris, T. o. cataspila, T. o. chichiriviche and T. o. venusta. Moreover, T. adiutrix should be regarded as a subspecies of T. dorbigni. All studied Trachemys species are inferred to have originated in the Late Miocene to Early Pliocene. The ancestor of the two subspecies of T. dorbigni colonized South America most probably prior to the establishment of the land bridge connecting Central and South America, whereas the two South American subspecies of T. ornata represent a younger independent immigration wave from Central America. © 2011 Blackwell Verlag GmbH. Source

Discover hidden collaborations