Sven Boström - Academia.edu (original) (raw)

Papers by Sven Boström

Research paper thumbnail of Description of two species of Chiloplectus Andrássy, 1984 (Nematoda: Plectidae) from Ukraine and a revised taxonomy of the genus

Nematology, 2000

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Research paper thumbnail of Swedish Plectida (Nematoda). Part 6. Neocamacolaimus parasiticus gen. n., sp. n

Zootaxa, 2014

A new genus Neocamacolaimus gen. n., with one new species N. parasiticus gen. n., sp. n. is descr... more A new genus Neocamacolaimus gen. n., with one new species N. parasiticus gen. n., sp. n. is described from the benthic polychaete Sphaerosyllis cf. hystrix collected in the Skagerrak off the west coast of Sweden. Neocamacolaimus gen. n. is placed in the family Camacolaimidae and is particularly characterised by having annulated cuticle with lateral alae; setiform cephalic sensilla located at level with amphids; amphidial fovea ventrally spiral; buccal cavity without armament; pharynx muscular; nerve ring located at base of pharynx; male reproductive system diorchic with outstretched testes; spicules weakly arcuate with straight manubrium; gubernaculum absent; alveolar supplements located in the pharyngeal region; tubular supplements absent; tail conoid; caudal glands and spinneret present. Juveniles of this genus are particularly characterised by their parasitic lifestyle and the following unique morphological features: lips form a dorso-ventrally elongated perioral disc with intern...

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Research paper thumbnail of Design and evaluation of nematode 18S rDNA primers for PCR and denaturing gradient gel electrophoresis (DGGE) of soil community DNA

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Research paper thumbnail of Descriptions of species of Stegelleta Thorne, 1938 (Nematoda, Rhabditida, Cephalobidae) from California, New Zealand and Senegal, and a revision of the genus

European Journal of Taxonomy, 2014

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Research paper thumbnail of Temporal dynamics of soil nematode communities in a grassland plant diversity experiment

Soil Biology and Biochemistry, 2011

We report here on an 8-year study examining links between plant and nematode communities in a gra... more We report here on an 8-year study examining links between plant and nematode communities in a grassland plant diversity experiment, located in the north of Sweden on previous agricultural soil. The examined plots contained 1, 4 and 12 common grassland plant species from three functional groups; grasses, legumes and forbs. The same plant species composition was maintained in the plots

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Research paper thumbnail of Effects of the nematofauna on microbial energy and matter transformation rates in European grassland soils

Plant and Soil, 1999

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Research paper thumbnail of <strong>Swedish Plectida (Nematoda). Part 5. <em>Rhadinema</em> <em>timmi</em> (Vitiello, 1971) comb. n.</strong>

Zootaxa, 2014

Leptolaimus timmi Vitiello, 1971 is redescribed from bottom sediments collected in the Skagerrak ... more Leptolaimus timmi Vitiello, 1971 is redescribed from bottom sediments collected in the Skagerrak off the west coast of Sweden. New morphological data necessitate the transfer of this species to the genus Rhadinema Cobb, 1920. The main diagnostic characters of Rhadinema timmi (Vitiello, 1971) comb. n. include: 1.3-1.8 mm long body; rounded labial region weakly offset from body contour; cephalic setae 2-4 µm long; amphid located 12-19 µm from anterior end; first body pore located 22-30 µm from anterior end; lateral field absent; stoma tubular: cheilostom with six weakly cuticularised longitudinal rugae, gymnostom with sclerotized bar-shaped rhabdia, stegostom long, tubular; female without supplements, vagina without pars refringens, vulva midventral; male with 10-11 tubular and without alveolar supplements; spicules arcuate and 21-30 µm long.

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Research paper thumbnail of <strong>Swedish Plectida (Nematoda). Part 4. The genus <em>Leptolaimus</em> de Man, 1876</strong>

Zootaxa, 2013

Twelve known and nine new species of Leptolaimus are described from bottom sediments collected in... more Twelve known and nine new species of Leptolaimus are described from bottom sediments collected in marine habitats of Sweden, including the Bothnian Sea and Bothnian Bay, the Baltic Sea proper, Gullmarn Fjord and the Skagerrak. Three of these species have been previously recorded in Sweden while nine are new records for the Swedish fauna. The following known species are redescribed: Leptolaimus papilliger de Man, 1876, L. cupulatus Lorenzen, 1972, L. danicus Jensen, 1978, L. donsi (Allgén, 1946) comb. n., L. mixtus Lorenzen, 1972, L. pellucidus (Southern, 1914) comb. n., L. venustus Lorenzen, 1972, L. lorenzeni (Boucher &amp;amp;amp;amp;amp; de Bovée, 1972) comb. n., L. alatus Vitiello, 1971, L. macer Lorenzen, 1972, L. septempapillatus Platt, 1973, L. elegans (Schuurmans Stekhoven &amp;amp;amp;amp;amp; De Coninck, 1933) Gerlach, 1958. Leptolaimus primus sp. n. is characterised by the 319-472 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5-2.0 µm long; amphid located 7.0-11.5 µm from anterior end; first body pore located 18.5-28.0 µm from anterior end; lateral field originating 35 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and with four alveolar supplements, alveolar supplements without sclerotized inner ring; spicules arcuate and 13.5-16.0 µm long. Leptolaimus secundus sp. n. is characterised by the 576-645 µm long body; rounded labial region continuous with body contour; cephalic setae 2.0 µm long; amphid located 6.5-7.0 µm from anterior end; first body pore located 23.0-28.5 µm from anterior end; lateral field originating 18.0-23.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with single tubular and 9-15 alveolar supplements, tubular supplement weakly arcuate with blunt tips, alveolar supplements with sclerotized lining; spicules arcuate and 23.0-26.5 µm long. Leptolaimus tertius sp. n. is characterised by the 576-579 µm long body; rounded labial region continuous with body contour; cephalic setae 2 µm long; amphid located 4-5 µm from anterior end; first body pore located 21.0-23.5 µm from anterior end; lateral field originating 26-29 µm from anterior end; male with four tubular and 7-10 alveolar supplements, tubular supplements weakly arcuate with blunt tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 25-26 µm long. Leptolaimus quartus sp. n. is characterised by the 597-686 mm long body; rounded labial region continuous with body contour; cephalic setae 2.0-3.5 µm long; amphid located 5.0-7.0 µm from anterior end; first body pore located 23.5-27.0 µm from anterior end; lateral field originating 19.0-27.0 µm from anterior end; male with three tubular and 8-9 alveolar supplements, tubular supplements straight with blunt expanded tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 23.0-25.0 µm long. Leptolaimus quintus sp. n. is characterised by the 443-528 µm long body; rounded labial region continuous with body contour; cephalic setae 1.0-2.0 µm long; amphid located 7.0-10.0 µm from anterior end; first body pore located 18.0-28.5 µm from anterior end; lateral field originating 25.0-41.0 µm from anterior end; female with two tubular supplements (one just posterior to cardia and one in front of anus), vagina without pars refringens, vulva right-sublateral; male with 8-10 tubular and without alveolar supplements, tubular supplements weakly arcuate with anchor-like tips; spicules arcuate and 17.0-22.0 µm long. Leptolaimus sextus sp. n. is characterised by the 626-728 µm long body; truncated labial region offset from body contour; cephalic setae 1.5-2.0 µm long; amphid located 8.0-12.0 µm from anterior end; first body pore located 41.0-48.5 µm from anterior end; lateral field originating 28.0-41.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with five (rarely six) tubular and without alveolar supplements, tubular supplements weakly S-shaped with bifid tips; spicules arcuate and 39.0-46.0 µm long. Leptolaimus septimus sp. n. is characterised by the 679-850 µm long body; truncate labial region offset from body contour; cephalic setae 2.5-3.5 µm long; amphid located 8.5-11.5 µm from anterior end; first body pore located 37.0-44.0 µm from anterior end; lateral field originating 26.5-37.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with four (rarely five) tubular and without alveolar supplements, tubular supplements weakly S-shaped, with bifid or blunt tips; spicules arcuate and 31.0-33.5 µm long. Leptolaimus octavus sp. n. is characterised by the 541-638 µm long body; truncate labial region continuous with body contour; cephalic setae 1.5-2.0 µm long; amphid located 8.5-12.0 µm from anterior end; first body pore located 31.5-41.0 µm from anterior end; lateral field…

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Research paper thumbnail of Design and evaluation of nematode 18S rDNA primers for PCR and denaturing gradient gel electrophoresis (DGGE) of soil community DNA

Soil Biology and Biochemistry, 2003

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Research paper thumbnail of Nematodes, rotifers and tardigrades from nunataks in Dronning Maud Land, East Antarctica

Polar Biology, 1995

... tude 1200-1300 m, size 500 x 200 m) on 31 January 1992. ... ca = Physcia caesia; Pr cr = Pras... more ... tude 1200-1300 m, size 500 x 200 m) on 31 January 1992. ... ca = Physcia caesia; Pr cr = Prasiola crispa; Ps mi =Pseudephebe minuscula; Rh me =Rhizoplaca melanophthalma; Xa ca = Xanthoria candelaria; Xa el = Xanthoria elegans; Um ap = Umbilicaria aprina; - = not present ...

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Research paper thumbnail of Description of Scottnema lindsayae Timm, 1971 (Rhabditida: Cephalobidae) from Taylor Valley, Antarctica and its phylogenetic relationship

Polar Biology, 2011

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Research paper thumbnail of Description of Deleyia gen. n. with a discussion of its phylogenetic relationships to the genera Daubaylia Chitwood & Chitwood, 1934 and Myolaimus Cobb, 1920 (Nematoda: Rhabditida)

Nematology, 2006

The new genus Deleyia gen. n., including two new species, D. poinari gen. n., sp. n. and D. aspic... more The new genus Deleyia gen. n., including two new species, D. poinari gen. n., sp. n. and D. aspiculata gen. n., sp. n., is described from terrestrial material (rotting wood and moss) in Ukraine. The new genus is inter alia characterised by the outer cuticular layer being defoliated along most of the body, except for labial region and tail posterior to phasmid, forming a cuticular sheath around the body and a vulval cuticular sac in females, and reduced stoma and basal bulb. Deleyia poinari gen. n., sp. n. is separated from D. aspiculata gen. n., sp. n. by a shorter body (L = 600-831 vs 756-945 ¿m), a shorter PUS (7-18 vs 44-69 ¿m), longer tail in both females and males (40-50 vs 32-38 ¿m and 37-48 vs 35 ¿m, respectively), and presence vs absence of spicules and gubernaculum. The phylogenetic position of Deleyia gen. n. and its relationships to the genera Daubaylia and Myolaimus are discussed.

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Research paper thumbnail of Panagrolobus vanmegenae, a new genus and species from The Netherlands and Ukraine, with taxonomic revision and two new species of the genus Teratolobus Andrássy, 1968 (Nematoda: Cephalobidae)

Nematology, 2006

Five species of the subfamily Acrolobinae, viz. Panagrolobus vanmegenae gen. n., sp. n., Teratolo... more Five species of the subfamily Acrolobinae, viz. Panagrolobus vanmegenae gen. n., sp. n., Teratolobus regulus Andrássy, 1968, T. obscurus sp. n., T. hamatus (Andrássy, 1986) comb. n. and T. similis sp. n., are described and illustrated from material collected in The Netherlands, Ukraine, Costa Rica, Mexico, Australia and South Africa. The new genus is characterised by a crown-shaped labial region

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Research paper thumbnail of Nematodes of the order Rhabditida from Andalucía Oriental, Spain. The genus Chiloplacus Thorne, 1937, with description of C. maginensis sp. n. and a key to species

Nematology, 2003

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Research paper thumbnail of Description of Aulolaimus multipapillatus sp. n. and A. nannocephalus Andrássy, 1972 with notes on taxonomy and phylogeny of the genus (Nematoda: Aulolaimidae)

Nematology, 2007

One new and one known species of Aulolaimus are described, viz. A. multipapillatus sp. n. from Is... more One new and one known species of Aulolaimus are described, viz. A. multipapillatus sp. n. from Israel and A. nannocephalus from Ukraine. Aulolaimus multipapillatus sp. n. is particularly characterised by a cuticle bearing ca 60 distinct longitudinal ridges, cuticle with distinct ornamentation on ventral body side anterior and posterior to vulva, 6-11 midventral sensilla anterior to cloaca, and spicules ca

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Research paper thumbnail of Morphology, molecular characterisation and systematic position of the genus Cynura Cobb, 1920 (Nematoda: Plectida)

Nematology, 2013

ABSTRACT Descriptions of three known species of Cynura, i.e., C. cerambus, C. klunderi and C. pap... more ABSTRACT Descriptions of three known species of Cynura, i.e., C. cerambus, C. klunderi and C. papillata, are given, including SEM micrographs of C. cerambus and a tabular compendium for all species of the genus. The phylogenetic relationships of C. klunderi are inferred from molecular data. Bayesian analyses of small subunit (SSU) of rRNA sequences support a position nested among the Plectidae suggesting the secondary simplification in the morphology of pharyngeal valvular apparatus in Cynura and the &#39;return&#39; from a terrestrial to a marine environment in this genus.

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Research paper thumbnail of Effects of plant species and plant diversity on soil nematodes – a field experiment on grassland run for seven years

Nematology, 2011

ABSTRACT Plant species identity and diversity may greatly influence the composition of the nemato... more ABSTRACT Plant species identity and diversity may greatly influence the composition of the nematode fauna. In this study the development of the nematode fauna was followed in a field experiment on arable soil with monocultures and mixtures of several plant species. Experimental plots were sown with one, four or 12 species of grass, legumes and forbs and were sampled four times in 7 years. Nematode diversity was little influenced by plant diversity. Due to a pronounced increase of Paratylenchus projectus populations, the Shannon diversity index decreased in several treatments towards the end of the experiment. Differences in nematode faunal composition among treatments increased with time. In spite of the rather long duration of the experiment, the faunal composition did not stabilise but changed continuously. The obligate plant feeders Tylenchorhynchus dubius, T. maximus and Pratylenchus spp. occurred in higher numbers in monocultures than in mixtures of several plant species. Among the microbivores, the abundance of some bacterial- and fungal-feeding nematode taxa seemed to be directly influenced by the plant species identity. In the plots with Trifolium spp. there was an increase of rapidly growing bacterial feeders belonging to Rhabditidae and Panagrolaimidae already after the first growing season. The abundances of some bacterial-feeding nematodes were correlated to total plant production. The numbers of the omnivorous Mesodorylaimus sp. appeared to be influenced by the degree of plant coverage. The abundance of several nematode taxa appeared to be little influenced by the composition of the vegetation. The plant feeder P. projectus and the bacterial feeder Prismatolaimus sp. reacted rather slowly and a distinct increase in numbers was only seen after 7 years, when P. projectus strongly dominated the fauna in several treatments. Among the bacterial feeders, some species with moderate growth rate belonging to Cephalobidae decreased with time in several treatments.

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Research paper thumbnail of Effects of moisture on soil microorganisms and nematodes: A field experiment

Microbial Ecology, 1986

The effects of soil moisture changes on bacteria, fungi, protozoa, and nematodes and changes in o... more The effects of soil moisture changes on bacteria, fungi, protozoa, and nematodes and changes in oxygen consumption were studied in a field experiment. In one plot the soil was drip-irrigated daily for 10 days, while an adjacent plot experienced one rainfall and was then allowed to dry out. Oxygen consumption was the parameter measured which responded most rapidly to changes in soil moisture content. Lengths of fluorescein diacetate-active hyphae paralleled oxygen consumption in both plots. Total hyphal length was not affected by one rainfall but increased from 700 mg(-1) dry weight soil to more than 1,600 m in less than 10 days in the irrigated plot. In the rain plot, bacterial numbers doubled within 3 days and declined during the following period of drought. In the irrigated plot, numbers increased by 50% and then remained constant over the duration of the study. Only small changes in protozoan numbers were observed, with the exception of the last sampling date in the irrigated plot when large numbers of naked amoebae were recorded 2 days after a large natural rainfall. Nematode numbers, especially obligate root feeders, increased in both treatments. The increases were caused by decoiling rather than growth. The results indicate that fungal respiration was dominating, while bacteria, lacking a suitable source of energy, were less active, except for the first days.

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Research paper thumbnail of Description of three known and two new species of the genus Tylocephalus Crossman, 1933, with a revised taxonomy of the genus and key to species of the subfamily …

Russian Journal of …, 2004

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Research paper thumbnail of Distribution patterns of microfauna (nematodes, rotifers and tardigrades) on nunataks in Dronning Maud Land, East Antarctica

Polar Biology - POLAR BIOL, 1996

In a previous paper the occurrence of nematodes, rotifers and tardigrades in 29 samples from nuna... more In a previous paper the occurrence of nematodes, rotifers and tardigrades in 29 samples from nunataks in Dronning Maud Land, East Antarctica taken 1991/1992 was recorded. In this study, a more thorough description of animal distribution is possible by adding 64 new samples (1993/1994), thus increasing the total number from these studies to 93 soil samples from 11 nunataks. The number of species recorded from the area has now increased from 27 to 34. The populations were patchily distributed and the species composition differed between nunatak areas in Vestfjella and Heimefrontfjella. In most samples only one or a few species of nematodes or tardigrades were found. The number of rotifer species in a particular sample varied from nought to seven. Rotifers occurred in most of the samples (76%) with a maximum density of 750 specimens/gram dry weight. The nematode distribution was more restricted. Nematodes were found in high abundance on only four of the nunataks and occurred in 35% of ...

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Research paper thumbnail of Description of two species of Chiloplectus Andrássy, 1984 (Nematoda: Plectidae) from Ukraine and a revised taxonomy of the genus

Nematology, 2000

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Research paper thumbnail of Swedish Plectida (Nematoda). Part 6. Neocamacolaimus parasiticus gen. n., sp. n

Zootaxa, 2014

A new genus Neocamacolaimus gen. n., with one new species N. parasiticus gen. n., sp. n. is descr... more A new genus Neocamacolaimus gen. n., with one new species N. parasiticus gen. n., sp. n. is described from the benthic polychaete Sphaerosyllis cf. hystrix collected in the Skagerrak off the west coast of Sweden. Neocamacolaimus gen. n. is placed in the family Camacolaimidae and is particularly characterised by having annulated cuticle with lateral alae; setiform cephalic sensilla located at level with amphids; amphidial fovea ventrally spiral; buccal cavity without armament; pharynx muscular; nerve ring located at base of pharynx; male reproductive system diorchic with outstretched testes; spicules weakly arcuate with straight manubrium; gubernaculum absent; alveolar supplements located in the pharyngeal region; tubular supplements absent; tail conoid; caudal glands and spinneret present. Juveniles of this genus are particularly characterised by their parasitic lifestyle and the following unique morphological features: lips form a dorso-ventrally elongated perioral disc with intern...

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Research paper thumbnail of Design and evaluation of nematode 18S rDNA primers for PCR and denaturing gradient gel electrophoresis (DGGE) of soil community DNA

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Research paper thumbnail of Descriptions of species of Stegelleta Thorne, 1938 (Nematoda, Rhabditida, Cephalobidae) from California, New Zealand and Senegal, and a revision of the genus

European Journal of Taxonomy, 2014

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Research paper thumbnail of Temporal dynamics of soil nematode communities in a grassland plant diversity experiment

Soil Biology and Biochemistry, 2011

We report here on an 8-year study examining links between plant and nematode communities in a gra... more We report here on an 8-year study examining links between plant and nematode communities in a grassland plant diversity experiment, located in the north of Sweden on previous agricultural soil. The examined plots contained 1, 4 and 12 common grassland plant species from three functional groups; grasses, legumes and forbs. The same plant species composition was maintained in the plots

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Research paper thumbnail of Effects of the nematofauna on microbial energy and matter transformation rates in European grassland soils

Plant and Soil, 1999

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Research paper thumbnail of <strong>Swedish Plectida (Nematoda). Part 5. <em>Rhadinema</em> <em>timmi</em> (Vitiello, 1971) comb. n.</strong>

Zootaxa, 2014

Leptolaimus timmi Vitiello, 1971 is redescribed from bottom sediments collected in the Skagerrak ... more Leptolaimus timmi Vitiello, 1971 is redescribed from bottom sediments collected in the Skagerrak off the west coast of Sweden. New morphological data necessitate the transfer of this species to the genus Rhadinema Cobb, 1920. The main diagnostic characters of Rhadinema timmi (Vitiello, 1971) comb. n. include: 1.3-1.8 mm long body; rounded labial region weakly offset from body contour; cephalic setae 2-4 µm long; amphid located 12-19 µm from anterior end; first body pore located 22-30 µm from anterior end; lateral field absent; stoma tubular: cheilostom with six weakly cuticularised longitudinal rugae, gymnostom with sclerotized bar-shaped rhabdia, stegostom long, tubular; female without supplements, vagina without pars refringens, vulva midventral; male with 10-11 tubular and without alveolar supplements; spicules arcuate and 21-30 µm long.

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Research paper thumbnail of <strong>Swedish Plectida (Nematoda). Part 4. The genus <em>Leptolaimus</em> de Man, 1876</strong>

Zootaxa, 2013

Twelve known and nine new species of Leptolaimus are described from bottom sediments collected in... more Twelve known and nine new species of Leptolaimus are described from bottom sediments collected in marine habitats of Sweden, including the Bothnian Sea and Bothnian Bay, the Baltic Sea proper, Gullmarn Fjord and the Skagerrak. Three of these species have been previously recorded in Sweden while nine are new records for the Swedish fauna. The following known species are redescribed: Leptolaimus papilliger de Man, 1876, L. cupulatus Lorenzen, 1972, L. danicus Jensen, 1978, L. donsi (Allgén, 1946) comb. n., L. mixtus Lorenzen, 1972, L. pellucidus (Southern, 1914) comb. n., L. venustus Lorenzen, 1972, L. lorenzeni (Boucher &amp;amp;amp;amp;amp; de Bovée, 1972) comb. n., L. alatus Vitiello, 1971, L. macer Lorenzen, 1972, L. septempapillatus Platt, 1973, L. elegans (Schuurmans Stekhoven &amp;amp;amp;amp;amp; De Coninck, 1933) Gerlach, 1958. Leptolaimus primus sp. n. is characterised by the 319-472 µm long body; rounded labial region continuous with body contour; cephalic setae 1.5-2.0 µm long; amphid located 7.0-11.5 µm from anterior end; first body pore located 18.5-28.0 µm from anterior end; lateral field originating 35 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and with four alveolar supplements, alveolar supplements without sclerotized inner ring; spicules arcuate and 13.5-16.0 µm long. Leptolaimus secundus sp. n. is characterised by the 576-645 µm long body; rounded labial region continuous with body contour; cephalic setae 2.0 µm long; amphid located 6.5-7.0 µm from anterior end; first body pore located 23.0-28.5 µm from anterior end; lateral field originating 18.0-23.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with single tubular and 9-15 alveolar supplements, tubular supplement weakly arcuate with blunt tips, alveolar supplements with sclerotized lining; spicules arcuate and 23.0-26.5 µm long. Leptolaimus tertius sp. n. is characterised by the 576-579 µm long body; rounded labial region continuous with body contour; cephalic setae 2 µm long; amphid located 4-5 µm from anterior end; first body pore located 21.0-23.5 µm from anterior end; lateral field originating 26-29 µm from anterior end; male with four tubular and 7-10 alveolar supplements, tubular supplements weakly arcuate with blunt tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 25-26 µm long. Leptolaimus quartus sp. n. is characterised by the 597-686 mm long body; rounded labial region continuous with body contour; cephalic setae 2.0-3.5 µm long; amphid located 5.0-7.0 µm from anterior end; first body pore located 23.5-27.0 µm from anterior end; lateral field originating 19.0-27.0 µm from anterior end; male with three tubular and 8-9 alveolar supplements, tubular supplements straight with blunt expanded tips, alveolar supplements with sclerotized inner ring; spicules arcuate and 23.0-25.0 µm long. Leptolaimus quintus sp. n. is characterised by the 443-528 µm long body; rounded labial region continuous with body contour; cephalic setae 1.0-2.0 µm long; amphid located 7.0-10.0 µm from anterior end; first body pore located 18.0-28.5 µm from anterior end; lateral field originating 25.0-41.0 µm from anterior end; female with two tubular supplements (one just posterior to cardia and one in front of anus), vagina without pars refringens, vulva right-sublateral; male with 8-10 tubular and without alveolar supplements, tubular supplements weakly arcuate with anchor-like tips; spicules arcuate and 17.0-22.0 µm long. Leptolaimus sextus sp. n. is characterised by the 626-728 µm long body; truncated labial region offset from body contour; cephalic setae 1.5-2.0 µm long; amphid located 8.0-12.0 µm from anterior end; first body pore located 41.0-48.5 µm from anterior end; lateral field originating 28.0-41.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with five (rarely six) tubular and without alveolar supplements, tubular supplements weakly S-shaped with bifid tips; spicules arcuate and 39.0-46.0 µm long. Leptolaimus septimus sp. n. is characterised by the 679-850 µm long body; truncate labial region offset from body contour; cephalic setae 2.5-3.5 µm long; amphid located 8.5-11.5 µm from anterior end; first body pore located 37.0-44.0 µm from anterior end; lateral field originating 26.5-37.0 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with four (rarely five) tubular and without alveolar supplements, tubular supplements weakly S-shaped, with bifid or blunt tips; spicules arcuate and 31.0-33.5 µm long. Leptolaimus octavus sp. n. is characterised by the 541-638 µm long body; truncate labial region continuous with body contour; cephalic setae 1.5-2.0 µm long; amphid located 8.5-12.0 µm from anterior end; first body pore located 31.5-41.0 µm from anterior end; lateral field…

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Research paper thumbnail of Design and evaluation of nematode 18S rDNA primers for PCR and denaturing gradient gel electrophoresis (DGGE) of soil community DNA

Soil Biology and Biochemistry, 2003

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Research paper thumbnail of Nematodes, rotifers and tardigrades from nunataks in Dronning Maud Land, East Antarctica

Polar Biology, 1995

... tude 1200-1300 m, size 500 x 200 m) on 31 January 1992. ... ca = Physcia caesia; Pr cr = Pras... more ... tude 1200-1300 m, size 500 x 200 m) on 31 January 1992. ... ca = Physcia caesia; Pr cr = Prasiola crispa; Ps mi =Pseudephebe minuscula; Rh me =Rhizoplaca melanophthalma; Xa ca = Xanthoria candelaria; Xa el = Xanthoria elegans; Um ap = Umbilicaria aprina; - = not present ...

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Research paper thumbnail of Description of Scottnema lindsayae Timm, 1971 (Rhabditida: Cephalobidae) from Taylor Valley, Antarctica and its phylogenetic relationship

Polar Biology, 2011

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Research paper thumbnail of Description of Deleyia gen. n. with a discussion of its phylogenetic relationships to the genera Daubaylia Chitwood & Chitwood, 1934 and Myolaimus Cobb, 1920 (Nematoda: Rhabditida)

Nematology, 2006

The new genus Deleyia gen. n., including two new species, D. poinari gen. n., sp. n. and D. aspic... more The new genus Deleyia gen. n., including two new species, D. poinari gen. n., sp. n. and D. aspiculata gen. n., sp. n., is described from terrestrial material (rotting wood and moss) in Ukraine. The new genus is inter alia characterised by the outer cuticular layer being defoliated along most of the body, except for labial region and tail posterior to phasmid, forming a cuticular sheath around the body and a vulval cuticular sac in females, and reduced stoma and basal bulb. Deleyia poinari gen. n., sp. n. is separated from D. aspiculata gen. n., sp. n. by a shorter body (L = 600-831 vs 756-945 ¿m), a shorter PUS (7-18 vs 44-69 ¿m), longer tail in both females and males (40-50 vs 32-38 ¿m and 37-48 vs 35 ¿m, respectively), and presence vs absence of spicules and gubernaculum. The phylogenetic position of Deleyia gen. n. and its relationships to the genera Daubaylia and Myolaimus are discussed.

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Research paper thumbnail of Panagrolobus vanmegenae, a new genus and species from The Netherlands and Ukraine, with taxonomic revision and two new species of the genus Teratolobus Andrássy, 1968 (Nematoda: Cephalobidae)

Nematology, 2006

Five species of the subfamily Acrolobinae, viz. Panagrolobus vanmegenae gen. n., sp. n., Teratolo... more Five species of the subfamily Acrolobinae, viz. Panagrolobus vanmegenae gen. n., sp. n., Teratolobus regulus Andrássy, 1968, T. obscurus sp. n., T. hamatus (Andrássy, 1986) comb. n. and T. similis sp. n., are described and illustrated from material collected in The Netherlands, Ukraine, Costa Rica, Mexico, Australia and South Africa. The new genus is characterised by a crown-shaped labial region

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Research paper thumbnail of Nematodes of the order Rhabditida from Andalucía Oriental, Spain. The genus Chiloplacus Thorne, 1937, with description of C. maginensis sp. n. and a key to species

Nematology, 2003

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Research paper thumbnail of Description of Aulolaimus multipapillatus sp. n. and A. nannocephalus Andrássy, 1972 with notes on taxonomy and phylogeny of the genus (Nematoda: Aulolaimidae)

Nematology, 2007

One new and one known species of Aulolaimus are described, viz. A. multipapillatus sp. n. from Is... more One new and one known species of Aulolaimus are described, viz. A. multipapillatus sp. n. from Israel and A. nannocephalus from Ukraine. Aulolaimus multipapillatus sp. n. is particularly characterised by a cuticle bearing ca 60 distinct longitudinal ridges, cuticle with distinct ornamentation on ventral body side anterior and posterior to vulva, 6-11 midventral sensilla anterior to cloaca, and spicules ca

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Research paper thumbnail of Morphology, molecular characterisation and systematic position of the genus Cynura Cobb, 1920 (Nematoda: Plectida)

Nematology, 2013

ABSTRACT Descriptions of three known species of Cynura, i.e., C. cerambus, C. klunderi and C. pap... more ABSTRACT Descriptions of three known species of Cynura, i.e., C. cerambus, C. klunderi and C. papillata, are given, including SEM micrographs of C. cerambus and a tabular compendium for all species of the genus. The phylogenetic relationships of C. klunderi are inferred from molecular data. Bayesian analyses of small subunit (SSU) of rRNA sequences support a position nested among the Plectidae suggesting the secondary simplification in the morphology of pharyngeal valvular apparatus in Cynura and the &#39;return&#39; from a terrestrial to a marine environment in this genus.

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Research paper thumbnail of Effects of plant species and plant diversity on soil nematodes – a field experiment on grassland run for seven years

Nematology, 2011

ABSTRACT Plant species identity and diversity may greatly influence the composition of the nemato... more ABSTRACT Plant species identity and diversity may greatly influence the composition of the nematode fauna. In this study the development of the nematode fauna was followed in a field experiment on arable soil with monocultures and mixtures of several plant species. Experimental plots were sown with one, four or 12 species of grass, legumes and forbs and were sampled four times in 7 years. Nematode diversity was little influenced by plant diversity. Due to a pronounced increase of Paratylenchus projectus populations, the Shannon diversity index decreased in several treatments towards the end of the experiment. Differences in nematode faunal composition among treatments increased with time. In spite of the rather long duration of the experiment, the faunal composition did not stabilise but changed continuously. The obligate plant feeders Tylenchorhynchus dubius, T. maximus and Pratylenchus spp. occurred in higher numbers in monocultures than in mixtures of several plant species. Among the microbivores, the abundance of some bacterial- and fungal-feeding nematode taxa seemed to be directly influenced by the plant species identity. In the plots with Trifolium spp. there was an increase of rapidly growing bacterial feeders belonging to Rhabditidae and Panagrolaimidae already after the first growing season. The abundances of some bacterial-feeding nematodes were correlated to total plant production. The numbers of the omnivorous Mesodorylaimus sp. appeared to be influenced by the degree of plant coverage. The abundance of several nematode taxa appeared to be little influenced by the composition of the vegetation. The plant feeder P. projectus and the bacterial feeder Prismatolaimus sp. reacted rather slowly and a distinct increase in numbers was only seen after 7 years, when P. projectus strongly dominated the fauna in several treatments. Among the bacterial feeders, some species with moderate growth rate belonging to Cephalobidae decreased with time in several treatments.

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Research paper thumbnail of Effects of moisture on soil microorganisms and nematodes: A field experiment

Microbial Ecology, 1986

The effects of soil moisture changes on bacteria, fungi, protozoa, and nematodes and changes in o... more The effects of soil moisture changes on bacteria, fungi, protozoa, and nematodes and changes in oxygen consumption were studied in a field experiment. In one plot the soil was drip-irrigated daily for 10 days, while an adjacent plot experienced one rainfall and was then allowed to dry out. Oxygen consumption was the parameter measured which responded most rapidly to changes in soil moisture content. Lengths of fluorescein diacetate-active hyphae paralleled oxygen consumption in both plots. Total hyphal length was not affected by one rainfall but increased from 700 mg(-1) dry weight soil to more than 1,600 m in less than 10 days in the irrigated plot. In the rain plot, bacterial numbers doubled within 3 days and declined during the following period of drought. In the irrigated plot, numbers increased by 50% and then remained constant over the duration of the study. Only small changes in protozoan numbers were observed, with the exception of the last sampling date in the irrigated plot when large numbers of naked amoebae were recorded 2 days after a large natural rainfall. Nematode numbers, especially obligate root feeders, increased in both treatments. The increases were caused by decoiling rather than growth. The results indicate that fungal respiration was dominating, while bacteria, lacking a suitable source of energy, were less active, except for the first days.

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Research paper thumbnail of Description of three known and two new species of the genus Tylocephalus Crossman, 1933, with a revised taxonomy of the genus and key to species of the subfamily …

Russian Journal of …, 2004

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Research paper thumbnail of Distribution patterns of microfauna (nematodes, rotifers and tardigrades) on nunataks in Dronning Maud Land, East Antarctica

Polar Biology - POLAR BIOL, 1996

In a previous paper the occurrence of nematodes, rotifers and tardigrades in 29 samples from nuna... more In a previous paper the occurrence of nematodes, rotifers and tardigrades in 29 samples from nunataks in Dronning Maud Land, East Antarctica taken 1991/1992 was recorded. In this study, a more thorough description of animal distribution is possible by adding 64 new samples (1993/1994), thus increasing the total number from these studies to 93 soil samples from 11 nunataks. The number of species recorded from the area has now increased from 27 to 34. The populations were patchily distributed and the species composition differed between nunatak areas in Vestfjella and Heimefrontfjella. In most samples only one or a few species of nematodes or tardigrades were found. The number of rotifer species in a particular sample varied from nought to seven. Rotifers occurred in most of the samples (76%) with a maximum density of 750 specimens/gram dry weight. The nematode distribution was more restricted. Nematodes were found in high abundance on only four of the nunataks and occurred in 35% of ...

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