Search publications of the members of the Royal Belgian institute of natural Sciences
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Imitation systems, monkey vocalization, and the human language
- In offering a detailed view of putative steps towards the emergence of language from a cognitive standpoint, Michael Arbib is also introducing an evolutionary framework that can be used as a useful tool to confront other viewpoints on language evolution, including hypotheses that emphasize possible alternatives to suggestions that language could not have emerged from an earlier primate vocal communication system.
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Villala Goemans and O'Brien, a new genus of Fulgoridae (Hemiptera, Fulgoromorpha) with three new species from Mexico, Belize, Guatemala, Honduras, and Costa Rica
- A new genus of Fulgoridae, Villala, with a long head projection, is described with three new species: V. canoi Goemans from Guatemala, Costa Rica, Belize, and Honduras; V. angelica O'Brien from Costa Rica, and V. platyrhina O'Brien from Mexico. A key to the species and comparative notes are included. © Taylor & Francis.
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The loess-palaeosol succession of Kurtak (Yenisei basin, Siberia): A reference record for the Karga Stage (MIS 3)
- The loess-palaeosol succession of Kurtak, along the western slope of the Yenisei Valley, is one of the best documented Late Pleistocene sequences in southern Central Siberia. The present paper deals with the Kurtak Pedocomplex and with the Chani Bay Complex preserved on the plateau and in a lateral depression respectively, which corre pond to the Karga Stage (MIS 3). For this sequence we obtained a detailed palaeoclimatic succession based on pedological and palynological data recording 14 short interstadial periods. The chronology of this record is well established by ca 100 radiocarbon dates on charcoal and wood remains, ranging from 42,520 to 25,710 BP. Botanical analysis shows a steppe-like vegetation with small tree populations (spruce, pine, birch) in lateral valleys during the colder periods. During the interstadial episodes spruce populations grew denser in the valleys, while scattered spruce, larch and pine trees expanded on the plateau. Therefore, the Kurtak Pedocomplex and Chani Bay Complex provide a unique climatic record for MIS 3, similar to the middle pleniglacial succession of the Dinkel Valley in the Netherlands and to loess-palaeosol records of Eastern and Central Europe. This means that the Siberian record shows a climatic sequence of global significance, and that the environmental conditions during MIS 3 were highly unstable at the Eurasian continent.
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Exploitation of kairomones and synomones by Medetera spp. (Diptera: Dolichopodidae), predators of spruce bark beetles
- The semioehemical relationships in a predator-prey-host plant system were studied by a series of multiple-choice field assays. The studied system included predatory flies of the genus Medetera (Diptera: Dolichopodidae), the bark beetles Ips typographus and Pityogenes chalcographus (Coleoptera: Curculionidae: Scolytinae) as prey and Norwegian spruce (Picea abies) as the host plant. Of the nine species of predators collected, only M. setiventris and M. melancholica provided sufficient data for statistical analysis. The response of the predators to monoterpenic products of the host (alpha-pinene, limonene, camphor), pheromone compounds of I. typographus (S-cis-verbenol and 2-methyl-3-buten-2-ol) and a mixture of the pheromones of I. typographys and P. chalcographus were investigated. Our field trials revealed that tree volatiles plus pheromones of the prey, and a pheromone mixture of both prey species were considerably more attractive to M. setiventris and M. melancholica than the individual chemicals. Medetera seem to respond to the stage of tree decay and the intensity of bark beetle infestation via the ratios of tree volatiles and/or prey pheromones.
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Mate choice in the hermaphroditic land snail Succinea putris (Stylommatophora: Succineidae)
- Internally fertilizing hermaphroditic animals show a bewildering variety of mating behaviours and mechanisms and many species have reciprocal sperm exchange. When matings are frequent and costly, partners are predicted to donate more sperm when they receive more sperm (i.e. conditional sperm exchange), but this has been shown experimentally only in sea slugs, free-living flatworms and possibly cestodes. We studied mate choice and sperm reciprocity patterns in the hermaphroditic land snail Succinea putris. Mate choice was random with respect to shell size. However, in matings where the partners were of unequal size, significantly more matings were observed where a small active individual mated on top of a larger inactive individual than the reverse. We suggest that this may be the result of mating on a vertical substrate or hanging underneath a horizontal substrate, because under these conditions it may be easier for a larger, inactive individual to carry a smaller, active one, than vice versa. The number of sperm transferred during mating was highly variable and was not related to the size of the donor, the size of the recipient, the size difference between the two partners or mating duration. Twelve of the 87 matings involved unilateral sperm exchange. There was no evidence for conditional sperm digestion. There was a significant, but weak positive relation between the numbers of sperm donated by the two partners. Hence, it remains unclear whether sperm exchange in S. putris is conditional or not. © 2005 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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New metallothionein mRNAs in Gobio gobio reveal at least three gene duplication events in cyprinid metallothionein evolution
- This paper reports the identification and analysis of the primary structure of three novel metallothionein cDNA sequences in the gudgeon, Gobio gobio (Cyprinidae). Two different 180 bp coding regions were identified, resulting in two MT isoforms differing in one amino acid. The primary structure of the amino acid sequence was compared to other cyprinid MT sequences. Furthermore, two differently sized cDNAs were discovered in one of the two transcripts. We present a phylogenetic comparison of our sequences to other, previously published cyprinid MT gene sequences. Our analysis reveals an unexpected complexity in cyprinid MT evolution, with at least three gene duplication events. Differences and homologies between the evolution of cyprinid MT genes are compared to other teleost families. Finally, possible implications for metallothionein classification are discussed. © 2005 Elsevier Inc. All rights reserved.
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Paracrenhydrosoma oceaniae sp. nov. (Copepoda: Harpacticoida), from Kongsfjorden, Northwest Svalbard (Arctic)
- Both sexes of a new species of Cletodidae belonging to the Acrenhydrosoma-lineage are described from material collected at Kongsfjorden (Svalbard) and attributed to the genus Paracrenhydrosoma Gee, 1999. Paracrenhydrosoma oceaniae sp. nov. is easily distinguished from its congeners by the reduced setal formula of the natatorial legs, lacking the inner subdistal seta on segment 3 of legs 3 and 4. Several other characteristics viz. antennular and antennal armature, and the free leg 5 exopodite in both sexes, are indications of its basal position in the genus.
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An assessment of animal species diversity in continental waters
- There is a need for monitoring the status and trends of freshwater biodiversity in order to quantify the impacts of human actions on freshwater systems and to improve freshwater biodiversity conservation. Current projects carrying assessment of freshwater biodiversity focus mainly on leading-better-known groups such as fish, or identify keystone species and/or endemic freshwater systems for conservation purposes. Our purpose is to complete these existing projects by providing quantitative estimates of species number for all freshwater groups on each continent and/or major eco-regions. This article present the results of the first implementation phase carried out from September 2002 to June 2003 and which addressed only freshwater animal species. The project consisted of: (1) compiling existing data from literature, web sites and museum collections; (2) contacting scientific experts of each group to provide a 'to the best of their knowledge, estimates of species numbers. In this study, we consider as true freshwater species, those that complete part or all of their life cycle in freshwater, and water-dependant species those that need freshwater for food or that permanently use freshwater habitats. The current order of magnitude for known freshwater animal species world wide is 100 000, of which half are insects. Among other groups, there are some 20 000 vertebrate species; 10 000 crustacean species and 5000 mollusc species that are either true freshwater or water-dependant species. The study highlighted gaps in the basic knowledge of species richness at continental and global scales: (1) Some groups such as Protozoa, nematodes or annelids have been less studied and data on their diversity and distribution is scarce. Because current richness estimates for these groups are greatly biased by knowledge availability, we can expect that real species numbers might be much higher. (2) Continents are not equal in the face of scientific studies: South America and Asia are especially lacking global estimates of species richness for many groups, even for some usually well-known ones such as molluscs or insects. The second phase of the project will address freshwater plants and algae. The present status should be considered as a first sketch of the global picture of freshwater biodiversity. We hope that this project will initiate interactive exchange of data to complete and update this first assessment. © Springer 2005.
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Taxonomy and systematics in biodiversity research
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Revision of the genus Thambemyia Oldroyd (Diptera: Dolichopodidae) with description of a new subgenus
- The genus Thambemyia Oldroyd is revised. Five species are recognized. Three new species - T. bisetosa, T. bruneiensis and T. hui - are described, and T. pagdeni Oldroyd, 1956 is redescribed. A new subgenus is founded for one new Japanese species, T. (Prothambemyia) japonica. A key to all known species of the genus is provided. Their distributions are also discussed. © 2005 The Entomological Society of Japan.
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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 Paleocene nyctitheriid insectivore from Inner Mongolia (China) and the origin of Asian nyctitheriids
- Nyctitheriids are primitive insectivores that were relatively abundant and diverse in North America and Europe during the middle Paleocene through to the middle Oligocene. The nyctitheriids from Asia are poorly known and show several distinctive characters. Here we describe the late Paleocene Asionyctia guoi gen. et sp. nov., the first fairly well known Asian nyctitheriid, from the Subeng locality near the city of Erlianhot (Erenhot) in Inner Mongolia, China. Among its most conspicuous features are the paraconid positioned high on p4, the rather primitive morphology and size of p3, the premolariform P4/p4 and the transverse upper molars with a small, straight postcingulum. Except for the paraconid positioned high on p4, these combined features are also present in other Asian nyctitheriids, but absent in North American or European forms. We performed a cladistic analysis, based on a set of 20 dental characters, to solve higher-level phylogenetic relations within Nyctitheriidae. The strict consensus tree groups all Asian forms in a single clade, for which we propose the rank of a subfamily and the name Asionyctiinae subfam. nov. Within Nyctitheriidae, a semimolariform P4/p4, as in Leptacodon tener, is considered primitive, and we consider the morphologically simplified P4/p4 of Asionyctiinae derived within Nyctitheriidae. Asionyctiinae can be derived from an American, primitive Leptacodon-like ancestor migrating into Asia, with the reduction of P4/p4 occurring on the Asian continent. Considering the derived morphology and the relatively high diversity of Asionyctiinae during the Asian late Paleocene, and the inferred conservative nature of the family Nyctitheriidae, we suggest an early Tiffanian time for the migration of nyctitheriids into Asia.
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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).
