Ultrastructure and taxonomy of Paraphysomonas (Chrysophyceae) and related genera 3

New observations are presented on the internal ultrastructure of the scale–bearing chrysophycean genera Chromophysomonas, Chrysosphaerella , the new genus Polylepidomonas and 15 species of Paraphysomonas. These data show that the pigmented genera Chromophysomonas, Chrysosphaerella and Polylepidomonas have a generally similar internal structure and that their taxonomic separation is based only on differences in scale structure. The structure of Paraphysomonas resembles that of these genera but the cells always possess a leucoplast rather than a chloroplast. In cell structure, the pigmented genera resemble the naked genus Ochromonas while Paraphysomonas resembles Spumella , the colourless counterpart of Ochromonas. Evaluation of the differences between these genera and the scale–bearing genera Mallomonas and Synura has led to the conclusion that Chromophysomonas, Chrysosphaerella, Polylepidomonas and Paraphysomonas should no longer be classified within the family Mallomonadaceae. The new family Paraphysomonadaceae is established to include Chrysophyceae with an Ochromonas type of cell structure but which also produce silica scales.     

The validity of the genus Spiniferomonas (Chrysophyceae)

Cells of Spiniferomonas bourrellyi Takahashi have been shown to possess a chloroplast. A procedure for examining the same cells by both light and electron microscopy was developed so that the structure of silica scales (which is diagnostic for the species) could be confirmed for cells clearly possessing chloroplasts. A previously published proposal invalidated the genus Spiniferomonas because the type species ( S. bourrellyi ) was found to be colourless and the new genus Chromophysomonas was erected to include all remaining pigmented species of Spiniferomonas . The findings reported here support reinstatement of S. blurrily as the validated type of the genus; Chromophysomonas is considered a redundant synonym.     

Validation of Paraphysomonas diademifera and Polylepidomonas vacuolata (Chrysophyceae)

An account is given on the validation of the combinations Paraphysomonas diademifera (Takahashi) Preisig & Hibberd (basionym: Ochromonas diademifera Taka_ hashi) and Polylepidomonas vacuolata (Thorasen) Preisig & Hibberd (basionym: Paraphysomonas vacuolata Thomsen).     

A new subspecies of Paraphysomonas punctata (Paraphysomonadaceae, Chrysophyceae)

A new subspecies, ssp. hexagona within the species complex of Paraphysomonas punctata is described. It is particularly distinguished by its large round to oblong perforations and also deviates in other respects from known subspecies of P punctata , so that it is here described as a new subspecies, ssp. hexagona . Type material has been collected in a small Danish pool in the Copenhagen area. A previous finding of scales with similar large perforations has been considered to be an indication of weakly silicified scales. This, however, cannot be the case since the present algae have been found in silica-enriched samples. Furthermore the pool is shallow and fully mixed throughout the year.     

Paraphysomonas faveolata sp. nov. (Chrysophyceae), a fourth marine species with meshwork body-scales

Paraphysomonas faveolata sp. nov., the eighth described species of this genus of colourless chrysophycean flagellates, has heterokont flagellation, parabasal nucleus and silicified body-scales. It is the fourth known species with meshwork scales, these being of two types: flat “cobweb” scales and scales with a planar “honeycombed” extension arising from a “cobweb” base. The organism is compared with the other species of the genus and the case considered for placing forms with meshwork scales in a new genus, separate from forms with spined scales. This step is not taken and the taxonomic status of the genus is discussed in relation to the Ochromonadaceae and other genera of the Synuraceae.     

Light and electron microscopical observations on the heterotrophic protist Thaumatomastix salina comb. nov. (syn. Chrysosphaerella salina) and its allies

The marine flagellates presently known as the chrysophytes Chrysosphaerella salina and C. tripus Takahashi & Hara have been refound and studied with light microscopy and whole mounts for electron microscopy. Based on material from Australia and Denmark (the latter from the type locality), C. salina is shown to be a colourless protist related to Reckertia sagittifera Conrad. It is characterized by a combination of flagellar features previously thought to be restricted to Reckertia , i.e. a short anterior flagellum which is scale-clad, and a longer, usually posterior but naked flagellum. The scales on the body are shown to be silicified. The new light microscopical studies have also shown considerable resemblance between C. salina, C. tripus and the genus Thaumatomastix Lauterborn. C. salina and C. tripus are therefore transferred to this genus together with Reckertia and the 2 marine species described since 1980 as belonging to Chrysosphaerella, C. triangulata Balonov and C. patelliformis Takahashi & Hara. Thaumatomastix bipartita sp.nov. is illustrated and described.
Chrysosphaerella appears to be a genus of photosynthetic, colony-forming chrysophytes restricted to freshwater habitats. Thaumatomastix is a genus of heterotrophic protists, usually solitary, which occurs in both marine and freshwater environments. The two genera show little, if any, phylogenetic relationship to each other.     

MOLECULAR PHYLOGENETIC ANALYSIS OF THE HETEROTROPHIC CHRYSOPHYTE GENUS PARAPHYSOMONAS (CHRYSOPHYCEAE), AND THE DESIGN OF rRNA-TARGETED OLIGONUCLEOTIDE PROBES FOR TWO SPECIES

Nanoflagellate protists are algae and protozoa (2– 20 μm in size) that play important ecological roles in freshwater and marine microbial communities as primary producers and as consumers of prokaryotic and eukaryotic prey. There is little biogeographical information for most of these minute protists despite their significant role in aquatic food webs. In addition, the evolutionary relationships among some of these species and their affinities to other protistan taxa are unclear. These circumstances are largely a consequence of the fact that small protists possess few readily apparent morphological features on which to base taxonomic and phylogenetic schemes and with which to identify them in natural assemblages. As an alternative approach for addressing these issues, we sequenced the small-subunit ribosomal RNA genes of four species of the colorless chrysophyte genus Paraphysomonas. A phylogenetic analysis based on that sequence information was performed, and oligonucleotide probes for two commonly occurring species of Paraphysomonas were designed and tested. Phylogenetic analyses of these four species confirmed the affinity of the genus Paraphysomonas with other chrysophyte species. High sequence similarity among three of the species (P. imperforata Lucas, P. bandaiensis Takahashi, and P. foraminifera Lucas) supported a previous phylogenetic grouping of these species based on the morphology of the scales produced by these species. In particular, sequence similarity between P. imperforata and P. foraminifera indicated that this speciation was a recent evolutionary event. However, a fourth species (P. vestita (Stokes) de Saedeleer) possessing similar scale morphology to P. bandaiensis, P. imperforata, and P. foraminifera showed considerable sequence dissimilarity in comparison to these latter three species. Oligonucleotide probes were successfully designed for the species P. imperforata and P. bandaiensis and applied together with a recently developed quantitative in situ hybridization procedure. The development of species-specific oligonucleotide probes for these nanoflagellate species and their application for counting nanoflagellates in natural water samples provide tools for studying these ecologically important species.     

Apparent global ubiquity of species in the protist genus Paraphysomonas

Evidence is presented for the ubiquity of protist species. Using the example of protists that leave traces (siliceous scales) of their recent population growth, we show that most - perhaps all species in the genus Paraphysomonas, are ubiquitous. Of the species recorded in surveys carried out worldwide, we have identified 78% of their number in 0.1 cm2 of sediment collected from a freshwater pond (total area 10(8) cm2) in England. Moreover, the pond appears to act like a microcosm of aquatic environments in general, for species that are globally rare or abundant, are likewise rare or abundant in the pond. We assume that the rate of neutral migration to the pond is greatest for the globally abundant species. As these species are probably capable of growth in a broad range of conditions, they will more frequently encounter the environment they require for population growth. Thus globally abundant species are also locally abundant in the pond - a pattern that will be amplified by periodic cyst production. Ubiquitous dispersal is probably driven by very high absolute abundance of individuals, and the water column of the pond was estimated to support >10(14) Paraphysomonas individuals. Ubiquity will dampen rates of speciation, and the evidence presented here indicates that global species richness of Paraphysomonas is indeed modest - perhaps close to what is already known.     

THE ULTRASTRUCTURE OF PYRAMIMONAS PSEUDOPARKEAE SP. NOV. (PRASINOPHYCEAE) FROM SOUTH AFRICA1

The ultrastructure of Pyramimonas pseudoparkeae sp. nov., a member of the class Prasinophyceae occurring in tidal pools along the east, south and west coast of South Africa, is described. The cell surface is covered by three distinctive body scales whilst the flagellar surfaces possess four types of scales. The structure of these scales is described. P. pseudoparkeae resembles Pyramimonas parkeae Norris and Pearson but differs in the structure of the type 2 body scale. The symmetry and ultrastructure of the cell are described with special attention given to the flagellar apparatus. Preliminary information on the life cycle of this species is presented. This new species is compared with other closely related members of the genus Pyramimonas.     

Fine structure of Pyramimonas octopus sp. nov., an octoflagellated benthic species of Pyramimonas (Prasinophyceae), with some observations on its ecology

A new octoflagellated species of Pyramimonas is described from three localities in Denmark. It is characterized by its ecology, being a marine psammophilic species associated with sand grains, and by details of the scaly covering on the cell surface. In the scale cover there are similarities to P. amylifera and to P. tetrarhynchus. P. octopus is distinguished by the possession of circular body scales of a type not previously found in the genus.
The general fine structure of the new species is described with emphasis on scale structure, the internal structure of the cell body and the flagella.     

Scale–bearing Chrysophyceae (Mallomonadaceae) from Central and Northern Canada

In this study, scale–bearing Chrysophyceae (Mallomonadaceae) have been examined by means of transmission and scanning electron microscopy. Lakes in four areas in central and northern Canada, viz. Experimental Lakes Area (ELA), in northwestern Ontario, Whiteshell Provincial Park and Southern Indian Lake in eastern and northern Manitoba, respectively, and Saqvaqjuac on the west coast of Hudson Bay in the Northwest Territories have been investigated. Forty–three species of the genera Mallomonas, Paraphysomonas, Spiniferomonas and Synura have been identified in addition to three species of the genus Chrysochromulina (Prymnesiophyceae). Ten species are new to Canada; five of these have not previously been recorded from North America. Paraphysomonas elegantissima sp. nov. is described. The composition of the Canadian chrysophycean flora is compared with the chrysophycean flora of North America as a whole.     

Taxonomic notes on the genus Plectocarpon (lichenicolous Ascomycetina)

The genus Plectocarpon is included in the Opegraphaceae (Opegraphales). It is distinguished by rounded mono- or multilocular, often stromatic ascomata with a reduced non-carbonized exciple, asci of the Opegrapha- typs, (1–)3(-6)-septate colourless spores with a distinct perispore and anastomosed paraphysoids. The genus includes at least 10 species, all lichenicolous on macrolichens, belonging mainly to the Peltigerales. 5 species are here described as new: P. lambinonii sp. nov. on Lobaria isidiosa and L. retigera from Papua New Guinea, Russia and Rwanda, P. macaronesiae sp. nov. on Lobaria puimonaria and L. suhlaevis from the Azores, the Canary Islands and Madeira, P. sampaianae sp. nov. on Pannaria sampaiana from Great Britain and Spain, P. scrobiculatae sp. nov. on Lobaria scrobiculata from France, Great Britain, Norway and Spain and P. usneae sp. nov. on Usnea exasperata from Rwanda. An additional undescribed species on Sticta leami from Papua New Guinea is mentioned. Most species form distinct galls on their host lichens.     

Observations on the microanatomy of the type species of Pyramimonas (P. tetrarhynchus Schmarda)

Salient features of microanatomy of Pyramimonas tetrarhynchus , type species of the genus, are described and illustrated. The species is shown to possess a flagellar scale reservoir comparable to that previously described for a marine species (P. amylifera) though somewhat simpler. The body scales are shown to arise directly from Golgi eisternae as in P. amylifera. Other features discussed include the flagellar roots and certain aspects of the mode of liberation of scales to the exterior. Participation by endoplasmic reticulum in the latter process is shown to be probable but there is no precise explanation forthcoming for the elaborate scale arrangement encountered both on the flagella and on the cell. Participation by cytoplasmic tubules is nevertheless effectively excluded for the latter.     

Le genre Petrascula Gümbel 1873, algue dasycladacée: Émendation,révision des espèces du genre,création de nouvelles espèces

The genus Petrascula has not been reviewed since J. Pia in 1920. At present, seven species are attributed to this genus. Different characteris have been used to define it by the authors. After abundant sampling in the Upper Kimmeridgian or the Southern Jura Mountains, the species-type has been reviewed and divided in two species, the second one named: Petrascula guembeli nov. sp.An other level of Portlandian age, in the same azea, is very rich in Petrascula piaiBachmayer, 1944. This species which has not been observed since that time is here reviewed. Associated with this species, a new one was found and described Petrascula? bugesiaca nov. sp., in spite a doubtful genus attribution.So many different species allow the review and emendation of the genus Petrascula. Then, the other species of the genus: P. globosa (Alth) P. herakiSokac & Nikler, P. illyricaSokac & Nikler, are discussed using the new definition.     

Scale evolution in Paraphysomonadida (Chrysophyceae): Sequence phylogeny and revised taxonomy of Paraphysomonas,new genus Clathromonas,and 25 new species

Heterotrophic chrysomonads of the genus Paraphysomonas are ubiquitous phagotrophs with diverse silica scale morphology. Over 50 named species have been described by electron microscopy from uncultured environmental samples. Sequence data exist for very few, but the literature reveals misidentification or lumping of most previously sequenced. For critically integrating scale and sequence data, 59 clonal cultures were studied light microscopically, by sequencing 18S ribosomal DNA, and recording scale morphology by transmission electron microscopy. We found strong congruence between variations in scale morphology and rDNA sequences, and unexpectedly deep genetic diversity. We now restrict Paraphysomonas to species with nail-like spine scales, establishing 23 new species and eight subspecies (Paraphysomonadidae). Species having base-plates with dense margins form three distinct subclades; those with a simple margin only two. We move 29 former Paraphysomonas species with basket scales into a new genus, Clathromonas, and describe two new species. Clathromonas belongs to a very distinct rDNA clade (Clathromonadidae fam. n.), possibly distantly sister to Paraphysomonas. Molecular and morphological data are mutually reinforcing; both are needed for evaluating paraphysomonad diversity and confirm excessive past lumping. Former Paraphysomonas species with neither nail-like nor basket scales are here excluded from Paraphysomonas and will be assigned to new genera elsewhere.     

Paraphysomonas corbidifera sp. nov., a marine,colourless, scale-bearing member of the Chrysophyceae

Paraphysomonas corbidifera sp. nov. has a spherical body bearing two flagella of unequal length, the longer possessing two rows of mastigonemes, the shorter smooth. The body is covered in scales of one basic form, open crown-like structures. The organism is compared with other members of the genus.     

The impacts of logging on the microhabitats used by two species of couas in the western forest of Madagascar

Habitat structure is important to consider in all ecological studies considering the relationships between animals and their environment. Habitat structure can be studied at different scales, from landscape to microhabitat. I studied here the response of two endemic terrestrial birds living in the dry forest of Madagascar. These birds belong to the genus Coua. The study is made at the microhabitat scale in a gallery forest, which has been logged selectively in order to limit the degradation of the forest. Selective logging is promoted to be respectful of the environment by allowing us to exploit the forest without destroying it and the wildlife encountered here. At the microhabitat scale, I underline that selective logging does not affect the Coquerel's coua, which can exploit new microhabitats and increase its density. On the other hand, the giant coua was affected by the restriction of optimal microhabitats for foraging. This species could be adapted to the new habitat by modifying its favourite foraging sites, but by decreasing also the population density. This species was affected by forest degradation, even considered as not destroying. At last, I considered how Coquerel's coua could be used as umbrella species for the endangered mesite.     

中国沟胸盲蝽属新种及新纪录属种记述(半翅目:盲蝽科)(英)

记述了一中国新纪录属,沟胸盲蝽属Solenoxyphus Reuter1875及隶于该属的两新种及一中国新纪录种,分别定名为黄沟胸盲蝽S. flavicans, sp. nov, 采自新疆维吾尔自治区乌鲁木齐市、甘河子县、阜康县,绿沟胸盲蝽S. viridulus, sp. nov.采自青海省乌兰县、新疆维吾尔自治区米泉县、阜康县,及中国新纪录蒿沟胸盲蝽S. lepidus(Puton1874)采自新疆维吾尔自治区乌鲁木齐市、阜康县、米泉县、木垒县及甘河子县,寄主均为蒿属植物Artemisia spp.。