Study of the genus Plectus Bastian, 1865 (Nematoda: Plectidae) from Iran

Three species of Plectus Bastian, 1865 viz., P. aquatilis and P. pusillus from Kerman province and P. velox from Alborz province, Iran are described and illustrated. Partial sequences of 18S region of ribosomal DNA gene were amplified for P. aquatilis and P. pusillus. The Blast results of population of P. aquatilis from Iran showed 8–10 nucleotides differences with populations of the same species (AF036602; GQ892827; AY284700) reported from the UK, Belgium and The Netherlands, respectively. Whereas Iranian population of P. pusillus showed 14–16 nucleotides differences with P. cf. pusillus (AY284705; AY284704) reported from The Netherlands. Molecular analysis revealed close relationship of the Iranian plectids with P. cf. parvus (AY284699) reported from The Netherlands. Phylogenetic relationships with other related species in the genus Plectus and closely related genera that are available in the GenBank are given.     

Nematodes,rotifers and tardigrades from nunataks in Dronning Maud Land,East Antarctica

Four species of nematodes, sixteen species of rotifers and seven species of tardigrades were found in samples from nunataks in Vestfjella and Heimefrontfjella in Dronning Maud Land, East Antarctica. The distribution of the fauna was very aggregated and some samples contained no animals. The degree of similarity in species composition between various nunataks was low. The highest abundances and number of species were found on the largest and highest nunataks in the most southern position.     

Ecology of Cryptopygus sverdrupi (Insecta: Collembola) from Dronning Maud Land,Antarctica

Summary Observations on the ecology of Cryptopygus sverdrupi Lawrence (Collembola, Isotomidae) were made with specimens from the Mühlig-Hofmannfjella, Dronning Maud Land, Antarctica. At an elevation of 1600 m a.s.l. the species was numerous in association with the green alga Prasiola on gravel fields and in crevices of large boulders. The distribution of size-classes in field samples suggested that the population comprised several overlapping generations. Growth and development is probably very slow due to long winters and daily periods of subzero temperatures in their microhabitat during the summer. Specimens collected in mid-January had a mean supercooling point of-24.6°C with small individual variations. The lack of high supercooling points in the summer suggests that the springtails feed on a nuleatorfree diet. The ability to supercool was increased during prolonged starvation and acclimation at 0,-4 and-8°C. Glycerol and other potential low molecular weight cryoprotective substances were demonstrated in specimens acclimated at-4 and-8°C. The species possessed a relatively high tolerance to desiccation.Publication No. 81 of the Norwegian Antarctic Research Expeditions (1984/85)     

Bird effects on organic processes in soils from five microhabitats on a nunatak with and without breeding snow petrels in Dronning Maud Land, Antarctica

Five microhabitat types with varying degrees of bird influence were examined. Soils were collected from open polygons, under mosses and bird nests on a nunatak with breeding snow petrels (Pagodroma nivea) and from open polygons and under mosses on a non-bird nunatak. Nutrient levels (total N and P, nitrate, nitrite and ammonia), moisture levels and δ ¹⁵N values were determined and the organic processes of nitrogen fixation (acetylene reduction) and soil respiration (CO₂ flux) were examined. Nests represented the most favourable microhabitat type for soil respiration having the highest nutrient levels and most favourable temperature and moisture regimes. The soils under mosses were also favourable and appear to act as a nutrient sink for nutrients originating from the nests. The open polygons were the least favourable for biological activity. There was little nitrogen fixation in any of the soils except for the soils under mosses from the non-bird nunatak. Fixation is possibly limited in favourable microhabitat types on the bird nunatak by high nitrogen levels. These results were confirmed by the δ ¹⁵N results, which had high values typical of a seabird signal in the soils from the bird nunatak and values near zero, typical of soils containing fixed nitrogen, on the non-bird nunatak. Received: 3 March 1997 / Accepted: 30 March 1998     

The persistence of the snow petrel (Pagodroma nivea) in Dronning Maud Land (Antarctica) for over 37,000?years

Two samples of snow petrel Pagodroma nivea mumiyo (solidified stomach oil) from Heimefrontfjella (74°34′36″S, 11°13′24″W) in Dronning Maud Land, Antarctica, were radiocarbon dated at 37,400 ± 1,500 and 3,120 ± 70 years old (dates are corrected for the ‘reservoir effect’). The age of the older sample provides further evidence that snow petrel colonies have existed in the mountain peaks of Dronning Maud Land since before the last glacial maximum (approx. 20,000–16,000 years ago). This finding also pushes back the estimated timing of establishment of snow petrel breeding colonies in this part of the continent by several thousand years. The variation in the accumulation rates of these two samples (1.6 and 35.2 mm per millennium, respectively) supports previous observations that mumiyo accumulation rates are highly variable and probably relate to site-specific factors affecting accumulation and degradation of the oil. Studies that help us understand historical bird population distributions in continental Antarctica can significantly aid the development and refinement of models that explain glacial advancement and retreat, the relationship between sea ice and population viability and, perhaps, predict species responses to future climate shifts.     

Spirobolbolaimus bathyalis,gen. nov., sp. nov. (Nematoda,Microlaimidae) from the Mediterranean (Calvi)

Spirobolbolaimus bathyalis gen. nov., sp. nov. is described from the continental slope off Calvi (Mediterranean). The new genus Spirobolbolaimus belongs to the Microlaimidae Micoletzky, 1922 and is closely related to the genus Bolbolaimus Cobb, 1920. It can be differentiated from Bolbolaimus by its multispiral amphideal fovea and by its six rows of postamphideal setae.     

Psychrobacter salsus sp. nov. and Psychrobacter adeliensis sp. nov. isolated from fast ice from Adelie Land, Antarctica

Nine psychrotolerant bacteria were isolated from fast ice in the middle of Geologie Archipelago, Adelie Land, Antarctica and were categorized into two groups, based on their SDS-PAGE profiles. Representatives from each of the two groups, namely strains DD 48^T and SJ 14^T exhibited phenotypic and chemotaxonomic characteristics confirming to the genus Psychrobacter. The 16S rRNA gene sequence indicated that the two isolates are closely related to each other and to the already reported fifteen species of Psychrobacter. Detailed studies on the phenotypic characteristics, chemotaxonomic properties and phylogenetic analysis of strains DD 48^T and SJ 14^T indicated that they are distinctly different from each other and the reported species of Psychrobacter. At the DNA-DNA hybridisation level, the two species exhibit less than 70% similarity. Thus, strains DD 48^T and SJ 14^T are identified as new species of the genus Psychrobacter for which the names Psychrobacter salsus sp. nov. and Psychrobacter adeliensis sp. nov. respectively are proposed.     

Halomonas glaciei sp. nov. isolated from fast ice of Adelie Land,Antarctica

Eleven psychrophilic bacteria were isolated from a solid layer of fast ice in the middle of Pointe-Geologie Archipelago, Adelie Land, Antarctica. The 11 isolates based on the phenotypic characteristics, chemotaxonomic and phylogenetic analysis have been identified as members of the genus Halomonas. All the isolates at the 16S rDNA sequence level were identical, possessed the 15 conserved nucleotides of the family Halomonadaceae and four nucleotides of the genus Halomonas. Therefore, the 16S rDNA sequence of DD 39 was used for calculating the evolutionary distances and for phylogenetic analysis. It was observed that DD 39 formed a robust cluster with H. variabilis, from which it differed by 0.7%. Further DNA-DNA hybridization studies indicated low DNA-DNA homology (15%) between H. variabilis and DD 39. Between the 11 Antarctic isolates the homology was >85%. In addition it was observed that DD 39 was different from H. variabilis in that it was psychrophilic, could tolerate only up to 15% sodium chloride, could not hydrolyse esculin, could not reduce nitrate, was urease negative, could not utilize glycerol as a carbon source, and was resistant to ampicillin and erythromycin and sensitive to nalidixic acid. In addition, it also exhibited distinct differences with respect to high content of C(16:1) and low levels of cyclo-C(17:0) and cyclo-C(19:0). DD 39 also differed from all the other reported species of Halomonas with respect to many phenotypic characteristics. It is proposed therefore that DD 39 should be placed in the genus Halomonas as a new species that is Halomonas glaciei. The type strain of H. glaciei is DD 39(T) (MTCC 4321; JCM 11692).     

Xylodon subflaviporus sp. nov. (Hymenochaetales,Basidiomycota) from East Asia

Xylodon subflaviporus (Hymenochaetales, Basidiomycota) is described as a new species collected from tropical and subtropical regions of East Asia. This new species is characterized by resupinate basidiocarps, a poroid hymenophore, pseudodimitic hyphal system, nodose-septate hyphae, four types of cystidia (capitate, acicular to cylindrical, subulate to ventricose, and apically-encrusted), and thin-walled, colorless, smooth and ellipsoid basidiospores. Bayesian, Maximum Likelihood and Maximum Parsimony algorithms were used to construct phylogenies inferred from the internal transcribed spacer (ITS) region of rDNA. Morphological and molecular studies, along with intercompatibility tests, confirmed the independent status of this species. Also, based on morphological and molecular evidence, six new combinations of Xylodon are proposed to accommodate species originally classified under Hyphodontia s.l., i.e. X. bubalinus, X. chinensis, X. mollissimus, X. nongravis, X. reticulatus and X. subtropicus. A key to known species of Hyphodontia s.l. with poroid, irpicoid or raduloid hymenophores is provided for the convenience in identification.     

Nudora omercooperi sp. nov. (Nematoda: Free-Living) from a unsual locality in South Africa

Summary Nudora omercooperi sp. nov. is described from a fresh-water spring below high tide mark at Claytons Rocks, South Africa. It is characterized by a massive gubernaculum and the form of various modifications of the cuticle.

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Résumé Nudora omercooperi sp. nov. est une forme plus originale avec des déformations caractéristiques de la cuticule et un gubernaculum très massif.

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Department of Zoology, British Museum (Natural History).     

Nanocnide zhejiangensis sp. nov. (Urticaceae: Urticeae) from Zhejiang Province,East China

Nanocnide zhejiangensis X.F. Jin & Y.F. Lu, a new species of Urticaceae from Zhejiang, east China, is described with illustrations. The new species is morphologically similar to Nanocnide japonica in having staminate inflorescence longer than leaves, but differs by having glabrous stems, petioles, peduncles and abaxial leaf surfaces, glabrous perianth lobes of staminate flowers, dorsally glabrous perianth lobes of pistillate flowers, and acuminate or solitary spinose–setaceous at the apex. Analysis based on ITS, atpF–H, atpB–rbcL and trnL–F sequences also demonstrate that Nanocnide japonica is the closest extant relative to the new species.     

Raphidascaris (Sprentascaris) lanfrediae sp. nov. (Nematoda: Anisakidae) from the fish Satanoperca jurupari (Osteichthyes: Cichlidae)

Raphidascaris (Sprentascaris) lanfrediae sp. nov. is described from the intestine of the freshwater fish Satanoperca jurupari (Heckel) (Cichlidae) from the Guamá River, state of Pará, Brazil. The prevalence in fish (n = 59) was 27% with intensity of one-124 (mean 16) nematodes per fish. The new species is characterized mainly by the markedly larger size of ventricular appendix in relation to the oesophagus, presence of short male caudal alae, 14-16 subventral pairs of preanal papillae and six pairs of postanal papillae.     

On the Identity and Nomenclature of Paracanthonchus caecus (Bastian, 1865), with a Redefinition of the Genus Paracanthonchus Micoletzky (Nematoda, Cyatholaimidae)

A historical review of the systematics of Paracanthonchus caecus (Bastian, 1865) and a comparison of specimens from different localities show that this "species" in fact comprises four distinct species. Paracanthonchus caecus Micoletzky, 1924 nec P. caecus (Bastian, 1865) is designated as the valid type species of the genus Paracanthonchus. P. heterodontus (Schulz, 1932) and P. thaumasius (Schulz, 1932) are re-established. P. caecm sensu Gerlach 1965 is considered as a distinct species: P. gerlachi sp.n. P. canadensis sp.n. is described and is very close to P. caecus Micoletzky, 1924. The subspecies P. caecus opthalmophorus (Steiner, 1921), different from the typical caecus by the presence of ocelli, is considered as a different species; we therefore propose P.ophthalmophorus (Steiner, 1921) stat.n. The genus Paracanthonchus is redefined.