Silvia Alfinito

Benthic algal mats of some lakes of Inexpressible Island (northern Victoria Land, Antarctica)

Benthic algal mats from four lakes located on Inexpressible Island (northern Victoria Land, Antarctica) were studied, analysing their structure and floristic composition. Thirty taxa of algae were identified: 11 Cyanophyta, 15 Bacillariophyta and 4 Chlorophyta. The lake mats contained from 15 (lake C) to 26 species (lake D). The number of diatom frustules in the mats varied from 771×103 (lake C) to 9428×103 frustules g-1 (lake B). In terms of floristic composition and macromorphology, these mats were observed to be very similar to moat mats described from Lake Gondwana (northern Victoria Land) and the Dry Valleys lakes of southern Victoria Land.

Floristic studies on freshwater algae of Lake Gondwana Northern Victoria Land (Antarctica)

Benthic algal mats and phytoplankton of Lake Gondwana (Northern Victoria Land, Antarctica) were investigated. Biomass, chlorophyll content and floristic analyses were carried out on algal mats. The mats are composed of two layers different in colour, floristic composition and chlorophyll content. The algal flora of the mats amount to 34 taxa (19 Cyanophyta, 7 Bacillariophyta, 8 Chlorophyta). The phytoplankton community is species-poor (only 5 taxa). Crytophyta account for about 98% of total algal density.

NAVICULA SKUAE SP. NOV., A FRESHWATER DIATOM FROM CONTINENTAL ANTARCTICA

The freshwater diatom Navicula skuae sp. nov. is described from benthic and floating algal mats of some lakes in northern Victoria Land (Antarctica). The detailed morphology of this species is examined using scanning electron microscopy (SEM). Navicula skuae is compared with other similar species.

The algal microflora of the salt works of Tarquinia (Italy)

The microflora and benthic microbial mats of the salt works of Tarquinia (Italy) are described. From 144 samples, 111 species and varieties of microalgae were identified. Diatoms prevailed up to 110‰. S. They were substituted by Cyanophyta at higher salinities. The microbial mats consisted of Cyanophyta, Beggiatoa spp., purple sulphur bacteria, and diatoms. Information on hypertonic resistance in some euryhaline species is given.

Desmids from Guma Valley (Sierra Leone, West Africa)

Twenty-two taxa of desmids are reported from a pool near Guma Valley (Sierra Leone). Six are new to the country. A new variety of Staurastrum hystrix (S. hystrix var. granulatum) is described.

Actinodontum, a new genus of Desmidiaceae (Streptophyta, Viridiplantae) from tropical Africa

A new desmid genus, Actinodontum Alfinito et Coesel, is described from mountain areas of tropical Africa. The newly described genus differs from the allied genus Actinotaenium by the presence of marked teeth at the base of each semicell that alternate with those on the other semicell. Morphology of the type species, Actinodontum lomaense (Alfinito et Mazzoni) Alfinito et Coesel, is dealt with in much detail. Cosmarium basituberculoides Bourrelly et Couté and Cosmarium elgonense Kusel-Fetzmann are transferred to the new genus. The geographical distribution of the genus Actinodontum is discussed.

Brachytheca inopinata (Desmidiaceae, Zygnematophyceae ), a new desmid from New Zealand

Abstract A new desmid species, Brachytheca inopinata Fumanti & Alfinito, is described from Lake Monowai, New Zealand, and the diagnosis of the genus Brachytheca is emended. The new species has cylindrical cells, about as long as broad, apical angles that are slightly rounded and a straight apex. The cell wall is smooth, with transverse rows of apical and subapical pores and without longitudinal grooves.