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Article Reference Inter and intra island introgression in a wolf spider radiation from the Galapagos and its implications for parallel evolution
Parallel radiations within island systems are often assumed to follow a simple scenario in which single colonization events are followed by in situ adaptive divergence. However, subsequent gene exchange after the initial colonization and during the divergence process might have important evolutionary impacts on species radiations. Gene exchange among ecologically similar species from different islands may lead to introgression of adaptive genetic variation and influence the parallel divergence process. In this study, we estimate levels of gene exchange within a wolf spider radiation of the genus Hogna Simon, 1885, from the Galápagos, wherein habitat specialization into ‘high elevation’ and ‘coastal dry’ species apparently evolved repeatedly on two islands. By using a multilocus approach we show that low levels of inter-island and relatively higher levels of intra island introgression shaped genetic variation in this species complex. Using these estimates, we demonstrate by means of a coalescence simulation that under these inter- and intra-island migration rates parallel evolution most likely evolves by introgression of adaptive alleles among islands, rather than through independent mutations despite the close genetic relationship of species within islands. As species phylogenies within radiations are frequently used to infer the divergence pattern, even relatively low levels of interspecific gene flow should not be neglected when interpreting parallel trait evolution.
Located in Library / RBINS Staff Publications
Article Reference The Tachakoucht–Iriri–Tourtit arc complex (Moroccan Anti-Atlas): Neoproterozoic records of polyphased subduction-accretion dynamics during the Pan-African orogeny
We report new mapping, tectonic, metamorphic and U–Pb zircon dating data on the polyphased Tachakoucht–Iriri and Tourtit arc-related units within the Moroccan Pan-African belt (Sirwa window, Anti-Atlas). The studied area contains four different sub-units, from south to north: (1) the Tachakoucht gneisses intruded to its northern part by (2) Iriri intrusions. To the north, the Tachakoucht–Iriri massif is thrusted by (3) the south-verging 760 Ma Khzama ophiolitic sequence intruded by (4) the Tourtit meta-granitic complex. The Tachakoucht gneiss represents former andesitic to dacitic porphyritic rocks crystallized around 740–720 Ma in an intra-oceanic arc setting (IOAS). Subsequently, it has been buried and metamorphosed to 700 °C, 8 kbar in response to early accretion of the arc onto the West African Craton (WAC). This tectono-metamorphic event also led to the dismembering and stacking of back-arc ophiolite onto the arc unit. Subsequently, the Iriri intrusions, a suite of hydrous mafic dykes (hornblende gabbro and fine-grained basalt) and ultramafic (hornblendite) plutons showing subduction zone affinities, intruded the Tachakoucht gneiss under P–T conditions of 750–800 °C and 2–5 kbar. Emplacement of Iriri intrusions led locally to pronounced partial melting of the Tachakoucht gneiss and to the production of leucogranitic melts. These melts crop out into the Iriri–Tachakoucht gneiss contacts as leucogneissic bands (former leucosomes, dated at 651 ± 5 Ma) but also intruded the Khzama ophiolite to form the Tourtit granite (dated at 651 ± 3 Ma). These ages (651–641 Ma) also constrain the timing of Iriri intrusion emplacement. The entire complex has been overprinted by a second deformation event under greenschist to amphibolite facies conditions marked by transposition of primary structures and a development of mylonitic shear zones. These results and those published on the Bou Azzer window show that two phases of subduction-related magmatism occurred in the Anti-Atlas belt and that they were separated by an early accretion of the intra-oceanic arc system (IOAS) onto the West African craton passive margin. Our interpretations also validate thermo-mechanical models predicting an intense perturbation of subduction dynamics during arc-continent collision (i.e. composite subductions, polarity reversal) which can expand the production of typical hydrous arc magma and induces a late magmatic phase after partial or total accretion of the IOAS.
Located in Library / RBINS Staff Publications
Article Reference The mitochondrial cytochrome <i>c</i> oxidase I gene reveals phylogeographic structure in the African Goshawk <i>Accipiter tachiro</i> (Accipitridae)
Located in Library / RBINS Staff Publications
Article Reference Second Record and DNA Barcode of the Ant Tyrannomyrmex rex Fernández (Hymenoptera: Formicidae: Myrmicinae)
Located in Library / RBINS Staff Publications
Article Reference The link between microbial diversity and nitrogen cycling in marine sediments is modulated by macrofaunal bioturbation
Located in Library / RBINS Staff Publications
Article Reference Two new species of <i>Leptanilloides</i> Mann, 1823 (Formicidae: Dorylinae) from the Andes of southern Ecuador
Two new species of Leptanilloides are described: L. copalinga Delsinne & Donoso sp. nov., and L. prometea Delsinne & Donoso sp. nov., based on workers collected in the leaf litter and soil of the Andes of southern Ecuador. Both species belong to the L. biconstricta species-group (formally diagnosed here). The metatibial gland, considered a synapomorphy for Dorylinae, is observed in L. prometea sp. nov. but seems absent in L. copalinga sp. nov. We provide a COI DNA barcode for both species and a revised key for the worker caste of all known species in the genus. We also describe a single male identified as a potential new Leptanilloides species on the basis of morphology. Furthermore, its mitochondrial COI gene sequence does not match any previously barcoded species. However, we refrain from giving it a specific name because of our lack of knowledge about the worker caste. So far, half of the 14 Leptanilloides species have been discovered above 1500 m in the mountain forests or páramos of the Ecuadorian Andes, confirming, if needed, the biological significance of these threatened habitats.
Located in Library / RBINS Staff Publications
Article Reference Daily temperature fluctuations alter interactions between closely related species of marine nematodes
Located in Library / RBINS Staff Publications
Article Reference Intraspecific functional trait variability does not result in higher fitness under thermal stress in a free-living marine nematode
Located in Library / RBINS Staff Publications
Article Reference In situ observations of suspended particulate matter plumes at an offshore wind farm, southern North Sea
Suspended particulate matter (SPM) plumes associated with the monopile foundations of the Belgian offshore wind farm (OWF) Belwind I were acoustically profiled by means of a Doppler current profiler (ADCP). Together with the analysis of a bottom lander dataset of optical and acoustic backscatter sensors (OBSs and ADPs respectively), the spatiotemporal SPM plume dynamics were inferred. The fieldwork comprised (1) near-bed measurements of hydrodynamics and SPM concentrations in the direct vicinity of the wind turbines, by means of a bottom lander over a spring–neap cycle in May 2010; this dataset represents a typically tidedriven situation because there was no significant meteorological forcing during the measurement period; (2) additional vessel-based measurements conducted in May 2013 to capture the SPM plumes inside and outside the OWF over part of a tidal cycle. Both in situ datasets revealed that the SPM plumes were generated at the turbine piles, consistent with aerial and space-borne imagery. The SPM plumes are well aligned with the tidal current direction in the wake of the monopiles, concentrations being estimated to reach up to 5 times that of the background concentration of about 3 mg/l. It is suggested that the epifaunal comunities colonizing the monopile surface and the protective rock collar at the base play a key role as source of the suspended matter recorded in the plumes. The organisms filter and trap fine SPM from the water column,resulting in predominant accumulation of SPM, including detritus and (pseudo-) faeces, at the base of the piles. When tidal currents exceed a certain velocity, fine particles in the nearbed fluff layer are re-suspended and transported downstream in the wake of the piles.
Located in Library / RBINS Staff Publications
Article Reference NEW FOSSIL HYAENODONTA (MAMMALIA, PLACENTALIA) FROM THE YPRESIAN AND LUTETIAN OF FRANCE AND THE EVOLUTION OF THE PROVIVERRINAE IN SOUTHERN EUROPE
The proviverrines from the Ypresian (MP7–MP10) and Lutetian (MP11–MP14) are represented mainly by species recorded in the northern and central parts of Europe (Paris Basin, Belgian Basin, Germany, Switzerland). Here, we describe fossils from southern France: Saint-Papoul (MP8 + 9; Aude) and Aigues-Vives 2 (?MP13; Aude). One dentary with secant molars from Saint-Papoul represents a new genus and species, Preregidens langebadrae. This taxon is possibly present in Avenay (France), the MP8 + 9 reference locality. One of the three dentaries discovered in Aigues-Vives 2 belongs to the hypercarnivorous Oxyaenoides schlosseri, previously represented by only two isolated lower molars. This dentary appears to be the most derived of the proviverrines. This species is possibly present in Saint-Martin-de-Londres (France), a locality that is considered to be close to the MP13 reference level. The two other dentaries from Aigues-Vives 2 support the presence of Eurotherium theriodis and provide the first possible evidence of sexual dimorphism in a proviverrine species. A phylogenetic analysis of the proviverrines is performed to resolve the phylogenetic position of the three taxa. This identifies a close relationship between the new genus (Preregidens) and Oxyaenoides. The new fossils allow the age of Saint-Papoul and Aigues-Vives 2 to be refined: the first locality is considered to be close in age to Avenay (Ypresian; France), while the second one seems to be close to Egerkingen c (Lutetian; Switzerland), which is considered to be possibly close in age to the MP13 reference level. Finally, the presence of O. schlosseri and E. theriodis in the southern part of France is compatible with the hypothesis that the mammals involved in the first intra-Eocene turnover migrated northwards.
Located in Library / RBINS Staff Publications