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Article Reference Diversity of rotifer fauna from five coastal peat swamps on phuket island, southern Thailand
A total of 133 rotifer species was identified from five coastal peat swamps on Phuket Island. Of these, Dicranophoroides sp.A and Harringia rousseleti were new to Thailand. The most speciose genus was Lecane (30.82\%), followed by Lepadella (12.03\%). The highest species richness occurred in Jae-Son (100 species), followed byJik (84 species), Jood (67 species), Mai-Khao (65 species) and Sra-Boua (48 species), respectively. One hundred and ninety-three rotifer species are now known from peat swamps in Thailand.
Located in Library / RBINS Staff Publications
Article Reference Octet Stream Ant biodiversity conservation in Belgian calcareous grasslands: Active management is vital
A list of ant species collected in eight calcareous grasslands in the Viroin valley (Viroinval, Belgium) is presented. Thirty species were identified, including Temnothorax albipennis, for the first time recorded in Belgium. Ant community composition and chorology of some ant species are discussed. Recommendations on how to use ant community composition and nest densities of several ant species to evaluate management in calcareous grasslands are given. It appears that in locations with encroachment of tall grasses (especially Brachypodium pinnatum) and spontaneous afforestation, due to a complete lack of or to inadequate management, most of the often rare xerophilic ant species are replaced by mesophilic, rather common species.
Located in Library / RBINS Staff Publications
Article Reference Esperiopsis koltuni sp. nov. (Demospongiae: Poecilosclerida: Esperiopsidae), a carnivorous sponge from deep water of the Sea of Okhotsk (North Pacific)
Esperiopsis koltuni, a new species of the sponge family Esperiopsidae, is described from deep water of the Sea of Okhotsk. The new species has a unique growth form: there is a basal plate with radiating cylindrical branches, whose oval flat distal parts bear filament-like outgrowths. Megascleres are arranged differently in the main part of branches and in their distal flat parts. The dermal membrane contains isochelae with protruding alae and abundant sigmancistras. Microscleres are represented by large anchorate spatuliferous isochelae, small isochelae, sigmas and sigmancistras. Esperiopsis koltuni sp. nov. is hermaphroditic, with parenchymella larva. The larval skeleton consists only of sigmas and sigmancistras. Esperiopsis koltuni sp. nov. can be easily distinguished from other Esperiopsis species by dimensions and combination of spicule types. In particular, it is the only species in the genus with three different size categories of styles. The new species lacks the aquiferous system, has a characteristic body plan with symmetrical lateral expansions, an unusual arrangement of microscleres in the dermal membrane and true sigmancistras. Moreover, prey capture by a filament-like outgrowth of the flat distal part was observed. All of these characteristics indicate that Esperiopsis koltuni sp. nov. is a carnivorous sponge.
Located in Library / RBINS Staff Publications
Article Reference Antrobathynella stammeri (Jakobi, 1954) : The first record of bathynellacea (Crustacea : Syncarida) in Belgium
Located in Library / RBINS Staff Publications
Article Reference Spiniferaphonte, a new genus of Laophontidae (Copepoda: Harpacticoida), with notes on the occurrence of processes on the caudal rami
A new genus and species of Laophontidae, Spiniferaphonte ornata n. gen., n. sp., is described from the coast of Kenya. The new genus is closely related to Laophontina and Wellsiphontina as shown by the following synapomorphies: a denticulate operculum, a sexually dimorphic P4 exopod (reduced chaetotaxy of the ultimate segment in the male), and the absence of sexual dimorphism in the P2 and P3 endopods. The two-segmented exopod of P1 and the presence of a seta on the endopodal part of the male P5 are plesiomorphies indicating that the new genus represents a separate lineage within this group. The proposal of the new genus Spiniferaphonte is supported by the following autapomorphies: three smooth setae on the female P5 exopod and a robust, dorsally bent, and strongly sclerotised caudal seta V. Within the Laophontidae, it is striking that the presence of distinct, thorn-like processes on the caudal rami is limited to interstitial genera. Distinct processes on the proximal segments of the antennule and a proximally thickened caudal seta V also appear to be associated with this interstitiality. These structures may play a role in the movement and the anchoring of the animals in their interstitial habitat.
Located in Library / RBINS Staff Publications
Article Reference Revision of the genus Tapholeon Wells, 1967 (Copepoda, Harpacticoida, Laophontidae)
To date, only two species are known in the laophontid genus Tapholeon Wells, 1967 (Copepoda, Harpacticoida). In the present contribution, a redescription of the type species T. ornatus Wells, 1967, based on the type material, is provided. Furthermore, two new species are described from the coast of Kenya, T. inconspicuus sp. nov. and T. tenuis sp. nov. Two species, formerly attributed to Asellopsis Brady and Robertson, 1873 (namely A. arenicola Chappuis, 1954 and A. chappuisius Krishnaswamy, 1957), are allocated to Tapholeon based on the absence of sexual dimorphism in the swimming legs P2-P4. The former of the two species is redescribed based on additional material from the Comoros. An updated generic diagnosis and a key to the six species of Tapholeon are included. © 2007 Taylor & Francis.
Located in Library / RBINS Staff Publications
Article Reference Whole-genome shotgun sequencing of mitochondria from ancient hair shafts
Although the application of sequencing-by-synthesis techniques to DNA extracted from bones has revolutionized the study of ancient DNA, it has been plagued by large fractions of contaminating environmental DNA. The genetic analyses of hair shafts could be a solution: We present 10 previously unexamined Siberian mammoth (Mammuthus primigenius) mitochondrial genomes, sequenced with up to 48-fold coverage. The observed levels of damage-derived sequencing errors were lower than those observed in previously published frozen bone samples, even though one of the specimens was >50,000 14C years old and another had been stored for 200 years at room temperature. The method therefore sets the stage for molecular-genetic analysis of museum collections.
Located in Library / RBINS Staff Publications
Article Reference Causes of variability in diatom and Phaeocystis blooms in Belgian coastal waters between 1989 and 2003: A model study.
Massive blooms of Phaeocystis colonies usually occur in the Belgian coastal zone (BCZ) between spring and summer diatom blooms but their relative magnitude varies between years. In order to understand this interannual variability, we used the biogeochemical MIRO model to explore the link between diatom and Phaeocystis blooms and changing nutrient loads and meteorological conditions over the last decade. For this application, MIRO was implemented in a simplified 3-box representation of the domain between the Baie de Seine and the BCZ. MIRO was run over the 1989–2003 period using actual photosynthetic active radiation (PAR), seawater temperature and riverine nutrient loads as forcing. The water mass residence time was calculated for each box based on a monthly water budget estimated from 1993–2003 water flow simulations of the three-dimensional hydrodynamical model COHSNS-3D. Overall MIRO simulations compare fairly well with nutrient and phytoplankton data collected in the central BCZ but indicate the importance of the hydrodynamical resolution frame for correctly describing the extremely high nutrient concentrations and biomass observed in the BCZ. Analysis of model results suggests that while interannual variability in diatom biomass depends on both meteorological conditions (light and temperature) and nutrient loads, Phaeocystis blooms are mainly controlled by nutrients. Further sensitivity tests with varying N and P loads suggest that only N reduction will result in significantly decreased Phaeocystis blooms without negative affects on diatoms, while P reduction will negatively affect diatoms. Moreover, Atlantic nutrient loads play such a great role in BCZ enrichment that reduction of Scheldt nutrient loads only is not sufficient to significantly decrease phytoplankton blooms in the BCZ. It is concluded that future nutrient reduction policies aimed to decrease Phaeocystis blooms in the BCZ without impacting diatoms should target the decrease of N loads in both the Seine and the Scheldt rivers.
Located in Library / RBINS Staff Publications
Article Reference Dispersal mechanisms in amphipods: A case study of Jassa herdmani (Crustacea, Amphipoda) in the North Sea
Jassa herdmani (Walker 1893), a tube-building amphipod typical of hard substrates, was found in large densities on shipwrecks from the Belgian part of the North Sea, in association with the hydrozoan Tubularia indivisa. In this area, shipwrecks only represent the source of hard substrates in an environment dominated by soft sediments. Nevertheless, the long-distance dispersal of Jassa species has never been investigated. Therefore, we tested the hypothesis of dispersal with currents, by investigating the behaviour of J. herdmani in the laboratory. Size distribution revealed that newly released juveniles (1 mm) predominated throughout the year and the lower frequency of the size class 1-3 mm indicates a high mortality or a dispersal at this life stage. Individuals of J. herdmani may initiate actively the transport by tidal or surface currents by swimming to the surface of the water or by floating at the surface, as suggested by behaviours noted in the laboratory. The reaction of the amphipods to a current was investigated in the laboratory. We could not detect any sexual function associated with drifting and there was also no preponderance of a size class in the drifting individuals. When testing different substrates, we observed a significant influence of the substrate type on the frequency at which drifting occurred: J. herdmani showed a better adherence on T. indivisa compared to other substrates. Finally, the amphipod showed also a preference for its host compared to other substrates, which suggests a possible detection mechanism. © 2007 Springer-Verlag.
Located in Library / RBINS Staff Publications
Article Reference Octet Stream Metallothionein gene and protein expression as a biomarker for metal pollution in natural gudgeon populations
Gudgeons (Gobio gobio) from historically Cd and Zn contaminated sites in Flanders (Belgium) were found to be resistant to elevated Cd levels. In previous work, this increased resistance was largely explained by increased metallothionein (MT) expression. Recently, environmental cleanup efforts resulted in a significant decrease in Cd concentrations in the surface water. In this study, we evaluated the use of hepatic metal and metallothionein (MT) concentrations as biomarkers of metal exposure before and after the cleanup. Hepatic MT mRNA levels were determined after the environmental metal levels decreased in order to assess the applicability of MT gene expression as an environmental biomarker in natural fish populations. Our data show that both metallothionein protein and gene expression have the potential to be sensitive biomarkers for metal exposure. Significant correlations were found (a) among accumulated metal concentrations and both MT protein and mRNA levels, and (b) between MT protein and mRNA levels. However, our data illustrated that while MT protein and gene expression give a quantitative picture of metal load at a single time point, quantitative information in natural populations cannot always be obtained when different time points (including different years) are compared, since MT gene and protein expression are affected by many other factors in addition to the metal load. Furthermore, the result of the environmental cleanup was reflected in a decrease of hepatic Cd concentrations. Zn remained the most important factor determining MT concentrations. Finally, two differently sized MT mRNAs were amplified to test the hypothesis that 3′-UTR length can offer a protective advantage in conditions of environmental stress. Our data provided no evidence to support this hypothesis. In contrast, the ratio of the long mRNA variant relative to total MT mRNA was surprisingly constant, and independent of exposure history. © 2007 Elsevier B.V. All rights reserved.
Located in Library / RBINS Staff Publications