The statospore of Mallomonas pseudocoronata (Mallomonadaceae, Chrysophyceae)

A mass encystment of Mallomonas pseudocoronata cells was observed in a polymictic lake from Southern Ontario, Canada. Scanning electron microscopy was used to describe its statospore, which is oval in shape, covered by short spines, and has a short cylindrical collar.     

Morphological variation and ecology of Mallomonas crassisquama (Chrysophyceae)

Siver, P. A. & Skogstad, A. 1988. Morphological variation and ecology of Mallomonas crassisquama (Chrysophyceae). - Nord. J. Bot. 7: 99–107. Copenhagen. ISSN 0107–055X.
Mallomonas crassisquama is one of the most common and widely distributed species of Mallomonas . In this study we compare the morphology and ecology of the species based on 309 collections from 67 localities in Connecticut (U.S.A.) and Norway. The taxon produces a very complex siliceous coat consisting of four scale and two bristle types all of which have considerable structural variation. A new variety, M. crassisquama var. papillosa is described. Bristle production was found to be temperature dependent where cells formed serrated or helmet bristles under cold or warm conditions, respectively. M. crassisquama was found to exist over wide temperature, conductivity, phosphorus and pH ranges, however, was absent in samples with a pH <5.5.     

Variation in silica scale morphology in Mallomonas pseudocoronata (Chrysophyceae)

It was previously thought that a form of Mallomonas pseudocoronata with scales lacking the reticulate shield pattern might be considered a separate subspecies. Until now, however, the unreticulated form has been so rare in collections that a conclusive decision on its taxonomic status has not been possible. An abundance of cells with the unreticulated scale form, as well as more typical forms, have been found recently in Ontario phytoplankton collections. All other features of cell and scale morphology of the unreticulated forms (bristle structure, cell and scale size and shape) are identical to those of the heavily reticulated forms. It was concluded that a wide range of scale reticulation (from complete absence to heavily silicified reticulations) characterizes this species and that only one genotype is responsible for the range in scale morphology now known for M. pseudocoronata .     

Mallomonas robusta (Chrysophyceae,Synuraceae): Electron microscopical study of silica armour

Mallomonas robusta (Matvienko)Péterfi & Momeu (Mallomonopsis robusta) has been investigated by transmission electron microscopy and is redescribed in detail. Its silica armour, consisting of scales and bristles, exhibits a very peculiar fine structural pattern. Differences and possible relationships with other species are discussed. The Romanian material is designated as the nomenclatural type (neotype).     

Three new species of Mallomonas (Chrysophyceae, Mallomonadaceae) from Lake Lanalhue, Chile

Three new species of the genus Mallomonas are described. Mallomonas rasilis sp. nov. belongs to the sect. Mallomonas , ser. Papillosae , while M. scalaris sp. nov. and M. lanalhuensis sp. nov. are members of the sect. Torquatae. They were found in Lake Lanalhue, Arauco Province, Chile. The taxonomy and distribution of these species is discussed, along with the morphology of cells, scales and bristles, based on scanning and transmission electron microscopy.     

Mallomonas alphaphora (Chrysophyceae), a new species from Western Australia

A new species ofMallomonas, M. alphaphora (Chrysophyceae), was found in freshwater ponds in the Perth region, Western Australia. It is distinguished from other species ofMallomonas by its very distinctive scale and bristle morphology and is placed in a new section,Alphaphorae, of the genusMallomonas. Dedicated to Prof. DrL. Geitler on the occasion of the 90th anniversary of his birthday.     

Mallomonas transsylvanica,spec. nova (Chrysophyceae), light and electron microscopical studies

The new speciesMallomonas transsylvanica is described in detail. Its silica armour has been examined by light and electron microscopy. Differences and possible relationships with other species are discussed.     

Mallomonas canina sp. nov. (Chrysophyceae), a new member of sect. Heterospinae

Mallomonas canina sp. nov. is described from a Danish lake by means of electron microscopy of scales and bristles and compared with the other members of the Mallomonas sect. Heterospinae Momeu & Péterfi.     

Mallomonas retrorsa, a new species of silica-scaled Chrysophyceae with backwards orientated scales

A new species, Mallomonas retrorsa , with a unique siliceous armour, is described from four slightly humic and acidic localities in Connecticut, U.S.A., each low in specific conductance. Cells of the new species have three types of siliceous scales each of which is asymmetric, domeless and arranged with their longitudinal axis parallel to the longitudinal axis of the cell. The scales are positioned such that the posterior rim of each scale faces the apical end of the cell. In addition, the new taxon has an apical whorl of very small, forward projecting paddle-shaped bristles that emerge from the rimmed ends of the apical scales, and an elongated caudal region.     

Revision of the Clinopodium abyssinicum group (Labiatae)

A tropical African group of species commonly included in the genus Satureja is revised and moved to the genus Clinopodium . Satureja abyssinica (Benth.) Briq. ssp. abyssinica and ssp. condensata (Hedberg) Seybold, S. paradoxa (Vatke) Engl. ex Seybold, S. robusta (Hook.f) Brenan and S. vernayana Brenan should be known under the following names: Clinopodium abyssinicum (Hochst. ex Benth.) Kuntze var. abyssinicum and C. abyssinicum var. condensatum (Hedberg) Ryding, C. paradoxum (Vatke) Ryding, C. robustum (Hook.f) Ryding and C. vernayanum (Brenan) Ryding, respectively. Satureja cacondensis (G. Taylor) Brenan, S. masukuensis (Baker) Eyles and S. myriantha (Baker) Brenan, including its varieties, are amalgamated and should be known by the name Clinopodium myrianthum (Baker) Ryding.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 391–408.     

Synuraceae (Chrysophyceae) in the Netherlands

Summary Investigations of phytoplankton biomass development and species succession in the Oude Waal near Nijmegen revealed the importance of the Chrysophyceae (Table I).Submicroscopical structures of the Chrysophyceae are known to be species-specific. So electronmicroscopical observations have been introduced into the research program. Special attention has been paid to the (scale-bearing) Synuraceae. The analysis of weekly taken samples in the year 1979 revealed a typical temporal distribution pattern of the Synuraceae, mainly controlled by temperature. Particulary the genusSynura showed a succession of four species:S. uvella dominated at water temperatures from 10–14°C,S. glabra from 14–16°C,S. curtispina from 10–19°C andS. petersenii occurred at water temperatures ranging from 0–21°C.     

Mallomonas fenestrata sp. nov. and M. perforata sp. nov. (Chrysophyceae, Mallomonadaceae) from tropical lakes

Two new species of Mallomonas (Chrysophyceae, Mallomonadaceae) are described from tropical lakes. M. fenestrata sp. nov. was found in Lago Tupé (Brazil) and M. perforata sp. nov. in Lake Danau Bratan (Indonesia), Negril ponds (Jamaica) and Marondera ponds (Zimbabwe).     

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.     

Revision of the aerea group of Chrysobothris (Coleoptera: Buprestidae)

Abstract. The aerea group of the genus Chrysobothris Eschscholtz, as characterized for the first time, includes eight species which occur in the south-western United States and in Mexico. The complicated taxonomic history and confused identity of some species is discussed in depth. Four Mexican species are redescribed in detail from type material: aerea Chevrolat, quadriplagiata Water-house, simplex Waterhouse, stellifera Waterhouse. Lectotypes are designated for the last two species. C.costifrons Waterhouse is considered to comprise three subspecies; two, C.c.rubiterga and C.c.baja are newly described. The remaining species in the group are C.bispinosa, chalcophoroides and serripes . Illustrations and keys to species and subspecies are provided.     

Revision of the umbellatarum species group of Anthaxia (Coleoptera: Buprestidae)

Abstract. The umbellatarum species group of the genus Anthaxia Eschscholtz of the Mediterranean region is characterized. A key is provided to distinguish this group from some superficially similar groups occurring in the same region, and to the five species and one subspecies referable to the group. Two new species, scylla and hamata are described. A.inculta ab. boissyi Obenberger is recognized as a distinct species and a lectotype is designated. A.domina Abeille is made a subspecies of umbellatarum (Fabricius). A.inculta ab. karamani Obenberger is found to be a colour form of cichorii (Olivier), not of umbellatarum as previously regarded. The other species belonging to the group is lusitanica Obenberger. All species belonging to the group are described.     

Mallomonadaceae (Chrysophyceae) from Malaysia and Australia

The Mallomonadaceae (Chrysophyceae) of Malaysia and Australia are described by scanning and transmission electron microscopy. Thirty taxa are reported from Malaysia, twenty eight for the first time. Eighteen taxa are reported from Australia, twelve for the first time. Twelve taxa are reported for the first time from the tropics. Four new taxa, Mallomonas ocellata sp. nov., M. tropica sp. nov., M. favosa f. gemina f. nov. and Chrysosphaerella astrea sp. nov. are described and the diagnosis of Mallomonas adamas Harris et Bradley is emended.     

The genera Cyclonexis and Chrysostephanosphaera (Chrysophyceae)

Two species of Chrysophyceae, Cyclonexis annularis and Chrysostephanosphaera globulifera are discussed. Observations are presented which suggest a relationship between these two organisms, though it is added that lacking definite proof of a relationship, one should continue to consider the two as distinct taxa.