Search publications of the members of the Royal Belgian institute of natural Sciences
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The female reproductive organ in podocopid ostracods is homologous to five appendages: Histological evidence from Liocypris grandis (Crustacea, Ostracoda)
- The giant ostracod, Liocypris grandis, found in South African temporary pools, has five pairs of additional appendage-like structures, seemingly associated with the Female Reproductive Organ (FRO). Original investigations of these structures by light and scanning electron microscopy could not unequivocally determine whether or not these structures are homologous to genuine appendages and if so, to how many. The present paper investigates morphology and attachment of these structures by frontal and transversal micro-sectioning (thickness = 1 μ m) of the caudal soft parts of mature females of L. grandis. It is found that all five appendages (R1-R5) have one individual attachment point where they enter into the FRO. Also R3(I) and R3(II) have a single attachment only, these two parts thus represent one single appendage. Whereas R1-R4 have clear lateral insertions, R5 is caudally positioned. The fusion of this latter appendage with the FRO occurs internally, at the posterior edge of the bulge of the FRO and is not externally visible. It is herewith thus accepted that R1-R5 are genuinely endogenous structures (and not, for example, exogenous parasites), that the five structures are homologous to five appendages, and not for example to parts of biramous appendages. It follows from this that the female reproductive organ is homologous to at least five, not to one segment. This would bring the number of (original) thoracic segments in podocopid ostracods to at least 8. An additional pair of triangular structures, inserted in between the two FRO is here described as structures 'X'. Their homology and function remain unknown. © Springer 2005.
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A new species of Glochinema (Epsilonematidae: Nematoda) from the oxygen minimum zone off Baja California, NE Pacific and phylogenetic relationships at species level within the family
- Glochinema spinithorni sp. nov. is described from muddy, bathyal sediments of the oxygen minimum zone (OMZ) of the north eastern Pacific Ocean off Baja California. It is characterized by a rather large body length (over 1 mm), a large number of body rings (242-282), sexual dimorphism in the number and position of pharyngeal thorns near the head region, cuticular ornamentation with numerous hairy spines and two sets of stronger spines ventrally in the anterior body half, mid-sized spiral amphids, and by the number and arrangement of ambulatory setae and long spicules (over 100 μm). The finding of a second OMZ Glochinema species with similar morphological characteristics supports the presumption that OMZs function as isolated habitats promoting endemism at low taxonomic levels. Results of phylogenetic analyses at the species level restricted to the Glochinematinae and Keratonematinae suggest that both OMZ species form a monophyletic group. An attempt was made to recognize phylogenetic relationships at species level within the family. The phylogenetic analyses were based upon a data matrix of 96 ingroup taxa and 25 characters. The results support the monophyly of the genera Leptepsilonema, Metepsilonema, Perepsilonema and Polkepsilonema (with or without Pternepsilonema).
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Monograph of the bees of the subfamily Nomioidinae (Hymenoptera: Halictidae) of Africa (excluding Madagascar)
- The paper presents the results of a study of 11863 specimens of Nomioidinae caught in Africa (excepting Madagascar) from 43 institutions and private collections. In total, 33 species belonging to three genera of Nomioidinae are found in the African fauna. All of the species are redescribed, figured and keyed. Their variability is analysed. Distributional maps in Africa are provided for all species. The types of nearly all the nominal taxa described earlier are examined. Seven new species and one new subspecies are described: Cellariella inexpectata n. sp., C. schwarzi n, sp., Ceylalictus congoensis n. sp., Nomioides deceptor capverdensis n. ssp., N. griswoldi n. sp., N. kenyensis n. sp., N. micheneri n. sp., and N. paulyi Pesenko, n. sp. New status is established for the following nominal taxa: Nomioides maculiventris var. fulviventris Blüthgen 1925 and N. somalicus ssp. kalaharicus Cockerell 1936 are considered separate species in the genus Cellariella: Nomioides karachensis var. desertorum Blüthgen 1925, a separate species in the genus Ceylalictus, Nomioides canariensis Blüthgen 1937, an insular subspecies of N. deceptor Saunders 1908; Nomioides maurus Blüthgen 1925, an African subspecies of N. minutissimus (Rossi 1790). The names Nomioides elbanus Blüthgen 1934 and N. squamiger Saunders 1908 are resurrected. The following new synonymies are established: Nomioides somalica ssp. kalaharica Cockerell 1936 = Cellariella brooksi Pesenko 1993; Nomioides somalicus Magretti 1899 = N. somalicus var. completus Blüthgen 1934 = N. atomellus Cockerell 1936; Nomioides deceptor Saunders 1908 = N. minutissimus var. deserticola Blüthgen 1925; Ceratina maculiventris Cameron 1905 = Nomioides maculiventris var. convergens Blüthgen 1934 = N. callonotus Cockerell 1936 = N. maculiventris var cyaneonotus Cockerell 1937; Nomioides minutissimus spp. maurus Blüthgen 1925 = N. senecionis Cockerell 1931 = N. maurus var. tingitanus Blüthgen 1933. Lectotypes are designated for the following nominal taxa: Ceratina maculiventris Cameron 1905; Nomioides callonotus Cockerell 1936; N. maculiventris var cyaneonotus Cockerell 1937, N. somalicus ssp. kalaharicus Cockerell 1936. The morphological evolution, phylogeny and geographical history of the subfamily Nomioidinae are presented and discussed. The paper includes 228 line drawings on 39 figures in the text, 124 colour, 8 black and white, 48 SEM photos and 33 maps on 20 plates, 7 tables, and provided with a list of 140 papers cited.
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Population genetics and identity of an introduced terrestrial slug: Arion subfuscus s.l. in the north-east USA (Gastropoda, Pulmonata, Arionidae)
- Several European species of the terrestrial slug genus Arion have been introduced into North America. A case in point is the species complex A. subfuscus s.l. which has become one of the most abundant slug taxa in North America. In Europe this complex consists of at least two cryptic species, viz. A. fuscus and A. subfuscus s.s., the latter of which is further subdivided in five strongly divergent mtDNA lineages (A. subfuscus S1-S5). In order to determine which of these A. subfsucus s.l. taxa are present in the NE USA and in order to assess their population genetic structure, we compared mtDNA, nDNA and allozyme variation between populations from the NE USA and Europe. Our results show that (1) at least A. subfuscus S1 has become successfully established in the NE USA, (2) founder effects are the most likely explanation for the loss of a large amount of molecular genetic variation in populations from the NE USA (i.e. a loss of 96\% of the 16S rDNA haplotypes, 67\% of the ITS1 alleles and 46\% of the alleles at polymorphic allozyme loci), and (3) part of the remaining genetic variation in NE USA populations was probably due to multiple introductions from the British Isles and the European mainland, and the hybrid structure of most of these source populations. Apparently, the extreme loss of molecular genetic variation in this introduced species has not prevented it from successfully establishing and spreading in novel environments. © Springer 2005.
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Extreme mtDNA divergences in a terrestrial slug (Gastropoda, Pulmonata, Arionidae): Accelerated evolution, allopatric divergence and secondary contact
- Extremely high levels of intraspecific mtDNA differences in pulmonate gastropods have been reported repeatedly and several hypotheses to explain them have been postulated. We studied the phylogeny and phylogeography of 51 populations (n = 843) of the highly polymorphic terrestrial slug Arion subfuscus (Draparnaud, 1805) across its native distribution range in Western Europe. By combining the analysis of single stranded conformation polymorphisms (SSCP) and nucleotide sequencing, we obtained individual sequence data for a fragment of the mitochondrial 16S rDNA and a fragment of the nuclear ITS1. Additionally, five polymorphic allozyme loci were scored. Based on the 16S rDNA phylogeny, five monophyletic haplotype groups with sequence divergences of 9-21\% were found. Despite this deep mitochondrial divergence, the haplotype groups were not monophyletic for the nuclear ITS1 fragment and haplotype group-specific allozyme alleles were not found. Although there is evidence for an accelerated mtDNA clock, the divergence among the haplotype groups is older than the Pleistocene and their current allopatric ranges probably reflect allopatric divergence and glacial survival in separate refugia from which different post-glacial colonization routes were established. A range-overlap of two mtDNA groups (S1 and S2, 21\% sequence divergence) stretched from Central France and Belgium up to the North of the British Isles. The nuclear data suggest that this secondary contact resulted in hybridization between the allopatrically diverged groups. Therefore, it seems that, at least for two of the groups, the deep mtDNA divergence was only partially accompanied by the formation of reproductive isolation. © 2005 European Society of Evolutionary Biology.
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On the evolution of the genus Microdarwinula Danielopol, 1968 (Ostracoda, Darwinuldiae) with the description of a new species from semi-terrestrial habitats in São Paulo State (Brazil)
- A new species in the genus Microdarwinula, M. inexpectata n. sp., is reported from semiterrestrial habitats in São Paulo State, Brazil. Until the present findings, M. zimmeri (Menzel, 1916) was the only recent species known in the genus. Comparisons of valve and soft part morphology within the genus and among genera in the family Darwinulidae, corroborate recent studies suggesting that Microdarwinula originated from an ancestor in the genus Penthesilenula. The two species of Microdarwinula are the only darwinulids to lack an externally visible brooding cavity in the carapace. This could be a neotenic character, while soft parts appear to be fully developed. Microdarwinula zimmeri has a world-wide distribution, but it was never found in South America. On the other hand, M. inexpectata n. sp. is so far known only from two localities in São Paulo State. © 2005 Koninklijke Brill NV.
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On new terrestrial ostracods (Crustacea, Ostracoda) from Brazil, primarily from São Paulo State
- Five new species and a new genus of terrestrial ostracods from Brazil are described: Callistocypris mckenziei sp. nov., Callistocypris rossettii sp. nov., Terrestricypris wurdigae sp. nov., Caaporacandona shornikovi gen. et sp. nov. and Caaporacandona iguassuensis gen. et sp. nov. This is the first time that Callistocypris Shornikov, 1980 and Terrestricypris Shornikov, 1980 have been found since their original description from the Solomon Islands. The family Terrestricyprididae Shornikov is here lowered to the rank of tribe within the Candoninae; this tribe comprises Terrestricypris, Terrestricandona Danielopol & Betsch, 1980 (from Madagascar) and Caaporacandona gen. nov. Putative heterochronic character evolution within this tribe (in valves A1 and A2) is compared to a parallel evolutionary pathway in another group of terrestrial ostracods, the Mesocypridini. The similarity between the terrestrial ostracod faunas of Brazil and the Western Pacific Islands (including New Zealand) and the dissimilarity between those of Africa and South America is indicated. The putative causality of the prevalence of asexual reproduction in terrestrial ostracods is briefly discussed. © 2005 The Linnean Society of London.
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Nearctic Achalcinae with a first Australachalcus species of North America (Diptera: Dolichopodidae)
- Both sexes of Achalcus bicolor sp.n., Achalcus longicercus sp.n., and Australachalcus latipennis sp.n. are described as additions to the Nearctic achalcine fauna. Diagnoses of five unnamed Achalcus species represented only by females are given. A key to Nearctic males and females including 10 unnamed species is provided. The new Achalcus records considerably extend the known distribution of the genus in North America, especially in the central and eastern states. Australachalcus latipennis sp.n. is the first known Nearctic species of this predominantly Neotropical and New Zealand genus. Achalcus bicolor sp.n. from Montana, Manitoba and Ontario clearly belongs to the Achalcus flavicollis species group. The eastern Achalcus longicercus sp.n. is not included in the latter species group due to the lack of a dorsal bristle on tibia I and the absence of a preapical anterodorsal bristle on femur III in both sexes. It features postgonites with strong hook-like apical processes possibly unique to this species. The presence and number of dorsal bristles on tibia I seem to be of both diagnostic and phylogenetic relevance. All northern achalcine species were collected between June and September, whereas some Californian species were taken in May and Australachalcus latipennis sp.n. from Arizona in October - November.
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Combining airborne and satellite remote sensing programs to repress illegal oil discharges in restricted sea areas
- In Belgium, the Management Unit of the North Sea Mathematical Models (MUMM) had mobilized remote sensing aircraft since 1991 to detect and prosecute illegal oil discharges at sea. MUMM's objective was to evaluate the effectiveness and operational character of satellite services for detecting oil spills, with regard to the detection of illegal oil spills at sea, and with respect to the added value for the present aerial surveillance program. The results of this 3-mo trial combined with 14 yr of experience in airborne remote sensing, indicated that remote sensing means used for the detection of illegal oil discharges at sea increased the chances of catching a polluter red-handed and improved the collection of evidence to strengthen the value of proof. The declining number of illegal oil discharges detected and the diminishing estimated annual oil volumes suggested a deterrent effect on the merchant marine by the physical presence of a surveillance aircraft. This is an abstract of a paper presented at the 28th Arctic and Marine Oil Spill Program Technical Seminar (Calgary, Alberta 6/7-9/2005).
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Monitoring organic microcontaminants in the marine environment: Principles, programmes and progress
- Monitoring trace organic microcontaminants in the marine environment has been on-going for several decades. However, the compounds considered in most programmes are still mainly the 'old' organochlorines, the polynuclear aromatic hydrocarbons, several metals and metal-containing compounds. However, the marine environment is threatened by a much larger suite of organic microcontaminants. In recent years, European and other international organisations have been moving towards extending their lists of priority hazardous substances. Simultaneously, there have become available novel analytical techniques that offer new possibilities for monitoring in the marine environment. © 2005 Elsevier Ltd. All rights reserved.
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Polychlorinated biphenyls in marine sediments from the southern North Sea and Scheldt estuary: A ten-year study of concentrations, patterns and trends
- The paper reports the concentrations and patterns of CBs in sediments of the Belgian part of the southern North Sea and the Scheldt estuary for the period 1991-2001. The long-term analytical performance was well within the quality assurance boundaries set at the outset of the study and is consistent with the state of the art for this type of analysis. The CB concentrations (given as the median of the sum of IUPAC Nos 28, 52, 101, 118, 138, 153 and 180) vary between 0.1 μg kg-1 and 50 μg kg-1 dry weight in the total sediment and it could be demonstrated that CB patterns in the fine fraction of the sediment were closely similar throughout the investigated area. Isolation of the fine fraction (<63 μm) by sieving can be regarded as a physical normalisation to reduce the differences in sediment granulometric composition. It allows for a better understanding of CB distribution and patterns and improves the trend analysis. A significant downward trend could not be found at any of the stations, which suggests that CB levels have not been changing in the area of interest in the past decade. © The Royal Society of Chemistry 2005.
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Use of the near infrared similarity reflectance spectrum for the quality control of remote sensing data
- The shape of water-leaving reflectance spectra in the near infrared range 700-900nm is almost invariant for turbid waters and has been analysed and tabulated as a similarity spectrum by normalisation at 780nm. This similarity spectrum is used here for the quality control of seaborne reflectance measurements and for the improvement of sky glint correction. Estimates of the reflectance measurement error associated with imperfect sky glint correction from two different wavelength pairs are shown to be nearly identical. A demonstration of residual reflectance correction for data collected in cloudy, high wave conditions has shown that this correction removes a large source of variability associated with temporal variation of the wave field. The error estimate applied here to seaborne measurements has wide-ranging generality and is appropriate for any water-leaving reflectance spectra derived from seaborne, airborne or satellite borne sensors provided suitable near infrared bands are available.
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Phylogeny of Labidodemas and the Holothuriidae (Holothuroidea: Aspidochirotida) as inferred from morphology
- The Holothuriidae is one of the three established families within the large holothuroid order Aspidochirotida. The approximately 185 recognized species of this family are commonly classified in five nominal genera: Actinopyga, Bohadschia, Holothuria, Pearsonothuria and Labidodemas. Maximum parsimony analyses on morphological characters, as inferred from type and nontype material of the five genera, revealed that Labidodemas comprises highly derived species that arose from within the genus Holothuria. The paraphyletic status of the latter, large (148 assumed valid species) and morphologically diverse genus has recently been recognized and is here confirmed and discussed. Nevertheless, we adopt a Darwinian or eclectic classification for Labidodemas, which we retain at generic level within the Holothuriidae. We compare our phylogeny of the Holothuriidae with previous classifications of its genera and subgenera, and make suggestions concerning possible systematic changes. © 2005 The Linnean Society of London.
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Rotifers from Kalasin Province, Northeast Thailand, with notes on new and rare species
- We report on a survey of rotifers from 30 habitats in Kalasin Province, Northeast Thailand, collected during Dec. 2001. One hundred and fifty species were identified. One of them, Lecane lungae sp. nov. is new to science, and two, L. opias (Harring and Myers), and L. stichoclysta Segers are new to the Oriental region and Thailand; the record of L. stichoclysta is the second record ever of the species after its description from Nigeria (Africa). In addition, we illustrate a remarkable morphological variant of Keratella cochlearis. These records, together with the new occurrences of other endemic rotifer species illustrate the remarkable diversity of the Thai rotifer fauna, and add to our knowledge of rotifer chorology.
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The use of mathematical models for estimating oil pollution damage at sea description of the system developed in the frame of the mare-dasm project
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The future of freshwater biodiversity research: An introduction to the target review
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Tale of a sleeping beauty: A new and easily cultured model organism for experimental studies on bdelloid rotifers
- We present the description of a new species of bdelloid rotifer, Adineta ricciae n. sp., which emerged from dry mud of Ryan's billabong, Victoria, Australia. Its conspicuous frontal eyes easily diagnose the species; it differs from A. oculata (Milne) by the position of the eyes and its general habitus. The animal came to our attention because it is exceptionally easy to culture, so that the species already is being used in diverse experimental studies utilising bdelloid rotifers as model organisms. © Springer 2005.
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Two new species of the genus Chersodromia Walker (Diptera: Hybotidae) from Southeast Asia
- Two new species of the genus Chersodromia Walker are described from mangroves of Singapore: C. nigripennis sp.n. and C. singaporensis sp.n. Palpal sensory pits are recorded for the first time in the genus and Tachydromiinae as a whole. They are present in both species. Some aspects of the male terminalia in Chersodromia are shortly discussed. Copyright © 2005 Magnolia Press.
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On a new Seison Grube, 1861 from coastal waters of Kenya, with a reappraisal of the classification of the Seisonida (Rotifera)
- On occasion of the discovery of a new species of a marine epizoic rotifer of the enigmatic Seisonidae, from Gazi Bay in Kenya, we reassessed the classification of the group. The taxon was until now known to contain only 2 species, viz. Seison nebaliae and S. annulatus, both of which live attached to Crustacea of the genus Nebalia. The new species, Seison africanus sp. nov., was diagnosed by its species-specific trophi morphology and relatively small size. A comparison with the 2 other known seisonid species reveals a sister group relationship between S. africanus sp. nov. and S. nebaliae, based on similarities in trophi structure and, accordingly, an assumed feeding mode and relationship with their hosts. The fundamental differences between these 2 commensal sister taxa and the ectoparasitic S. annulatus prompted a reevaluation of the generic classification of these animals. Accordingly, we propose to reestablish the genus Paraseison Plate, 1887 in order to accommodate P. annulatus (Claus, 1876) (comb. nov.).
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Multiple origins of tetraploid taxa in the Eurasian Bufo viridis subgroup
- We used Q-banding and analyzed nucleolar organizing regions (NORs) to study the cytogenetic evolution of tetraploids within the Palearctic Bufo viridis subgroup, the only known amphibian complex comprising di-, tri- and tetraploid bisexually reproducing taxa. We examined three diploid (2n) nominal taxa (Bufo viridis viridis, B. v. turanensis, B. v. kermanensis) from five Eurasian localities and six tetraploid (4n) nominal taxa (B. oblongus, B. o. danatensis, B. pewzowi pewzowi, B. p. taxkorensis, B. p. unicolor, B. p. strauchi) from eight Central Asian localities. Homeologous chromosomes of 2n and 4n toads exhibit a similar morphology. Silver-staining and in situ hybridization revealed terminal NORs in the long arms of chromosomes 6 in all 2n but in only two out of four chromosomes 6 in all 4n taxa. Q-banding and a rapidly evolving mitochondrial marker suggest at least two origination events for Asian 4n toads: "Western Central Asian tetraploids" (B. oblongus Nikolsky, 1896) exhibit distinct differences within some chromosome quartets, which are divisible into pairs of chromosomes and may be allopolyploid. In contrast, "Central Asian tetraploids" (B. pewzowi Bedriaga, 1898) showed homogenous Q-banding patterns within each quartet, suggesting autopolyploidy. In Northeastern Iran, we discovered a zone of either common ancestry or hybridization of 2n and Western Central Asian 4n toads. This raises intriguing questions about how diploid and tetraploid taxa may evolve by exchanging genetic material. © Springer 2005.
