Ultrastructure of three Species of Entomoneis (Bacillariophyta) from Lake Qinghai of China, with reference to the external areola occlusions.

Three sympatric Entomoneis species, found at the same specific locality in Lake Qinghai, China, are studied by using light and scanning electron microscope. Two species are proposed as new to science and named as E.sinensis sp. nov. and E.qinghainensis sp. nov. The third species is identified as E.paludosa (W. Smith) Reimer. Entomoneissinensis has a linear-lanceolate valve outline and Ƨ-shaped keel, bears two distinct 8-shaped loops formed by the valvocopula pars media in each cell and each of its stria is composed of either a long hymen strip or a long hymen strip plus one separated areola close to the raphe. Its hymen strip belongs to Type Two, which is a siliceous membrane strip perforated by two rows of linear pores next to transapical costae and two rows of rounded pores between these two rows of linear pores. Entomoneisqinghainensis has large cells, very high keel and evident hymen strip regions like a U-shaped neck pillow at the middle of valve face. Its hymen strip belongs to Type One, which is a siliceous membrane strip perforated by irregularly distributed round pores. Entomoneispaludosa also has the hymen strip regions that are worm-like and close to the raphe canal. Its hymen strip is same as that of E.qinghainensis. The two kinds of the outside areola occlusions in Entomoneis are compared, summarised and discussed.

Diatomasinensis: a new diatom species (Bacillariophyta) found in the brackish Lake Qinghai, China.

Lake Qinghai is an ancient brackish water lake in which several endemic diatom species have been discovered. In this study, a species of Diatoma is observed under light and scanning electron microscopy and described as new, Diatomasinensis sp. nov. The living cells of D.sinensis always lie in girdle view due to the cell depth being much larger than valve width (3.3-8.8 vs. 2.0-3.0 µm). The valves of D.sinensis are characterized by their narrow, linear-lanceolate outline, with capitate to subcapitate apices, the presence of two rimoportulae, one at each apex, embedded in the last rib or located among striae and a 4:2 configuration of girdle bands in normal vegetative cells, with four bands assigned to the epivalve and two to the hypovalve. The new taxon is compared with similar species from the genera Diatoma and Distrionella.

Two new freshwater species of Surirella (Bacillariophyta) from the Wuling Mountains, China.

Two sympatric Surirella species found at the same specific locality in the Wuling Mountains of China are documented with light and scanning electron microscope. Both species are new to science and named S.wufluminensis sp. nov. and S.suiningensis sp. nov. Surirellawufluminensis has large frustules that are either clockwise or counterclockwise twisted when viewed with the light microscope, and possesses distinctive fibulae, mound-like outgrowths on the valve surface throughout, raised longitudinal ridges on both sides of the raphe, and two helictoglossa-like processes at one apex internally. Surirellasuiningensis has narrowly ovate valve outline, distinctive fibulae, troughs alternating with crests from pole to pole, and two helictoglossa-like processes at one apex internally. These two species do not produce costae on the valve surface in contrast to many species in Surirella. This study provides a further two examples of the wide range of morphological diversity in the genus Surirella.