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2 heterotrichous and 9 hypotrichous ciliates including one new genus collected from the Yellow Sea and the Bohai Bay, north-eastern China are morphologically investigated based on living observations and using various silver impregnation methods: Protocruzia contraxMansfeld, 1923; Condylostoma magnumSpiegel, 1926; Holosticha mancaKahl, 1932; Oxytricha saltans (Cohn, 1866); Hemigastrostyla enigmatica (Dragesco & Dragesco-Kernéis, 1986) nov. gen., nov. comb.; Uronychia setigeraCalkins, 1902; Uronychia binucleataYoung, 1922; Uronychia transfuga (Müller, 1786); Euplotes minutaYocum, 1930; Aspidisca steini (Buddenbrock, 1920); Aspidisca leptaspisFresenius, 1865. Morphological characteristics and taxonomic position of all known Uronychia-species are briefly compared and discussed. About 3 Protocruzia-, 5 Uronychia- and 12 Aspidisca-species are considered as junior synonyms according to the results of our current studies. The hypotrich, Hemigastrostyla nov. gen., might be assigned to the family Oxytrichidae. Diagnosis of this new genus: body slightly cephalized; mostly 8–10 frontal, 5 ventral and a few extra lateroventral cirri which possibly derive from the 6th (right-most) cirral anlage during morphogenesis; caudal cirri present. Marine or brackish water forms. It is recognised from other oxytrichids by the cephalized body shape and possessing extra lateroventral cirri right to the transverse ones.

The flagellates of an Australian garden soil were studied by placing coverslips on wet soil and subsequently examining the coverslips by light microscopy. A number of genera and species were found which have not previously been reported from soil samples. Besides the three new species, Apusomonas australiensis sp. nov., Peltomonas hanelisp. nov., and Sciviamonas terricola gen. nov. sp. nov. they include species from the genera Amastigomonas, Cryptaulax, Paraphysomonas, and Protaspis. Among genera which have been reported from soils, we recorded a number of species previously unreported from soils: Petalomonas pusilla, Bicosoeca epiphytica, Bicosoeca mignotii, and Ancyromonas sigmoides. In addition, we extracted a number of forms which have been found in soil but which are usually not considered as members of the soil flagellate community. They are: Codosiga botrytis, Salpingoeca amphoridium, and Goniomonas truncata. Only a minority of the taxa recorded are thought of as common and widespread in soils, they include: Apusomonas proboscidea, and species of Cercomonas and Spumella. At least part of the difference between communities of flagellates from freshwaters and those of soils are due to different sampling methods and not only to the existence of different communities.

We estimated the rate of nucleotide substitution for the obligate freshwater fish ectoparasite, Ichthyophthirius, and its closest free-living relative, Ophryoglena, using an independently-timed event — the origin of freshwater fish in the fossil record. Based on this information, the rate of nucleotide substitution per site, per year, per lineage is 1.25 to 1.4 × 10⁻⁸ or 1% divergence per 72 to 80 million years (My). Using this rate, we determined that the origin of the ciliates (i.e. crown eukaryotes) is much older than previously speculated, dating back to the Paleoproterozoic some 1980 to 2200 million years ago (Ma). We also determined that the wellestablished lineages recognized as classes today (e.g. Spirotrichea, Oligohymenophorea, Nassophorea, Colpodea, Heterotrichea, Karyorelictea, and Litostomatea) diverged within 600-My of the ciliate-like ancestor diverging from the main eukaryotic line.

The macronucleus of vegetative cells of Blepharisma japonicum contains numerous discrete chromatin bodies and nucleoli of the compact type. The nucleoli contain very dense inclusions likely to be the dense fibrillar component of the nucleoli themselves. The macronuclear envelope displays tightly packed pore complexes. Until the 10th hour of conjugation, the old macronucleus shows the same fine structure as in vegetative cells. At 12 hours (approximately during metaphase I), the fibrillar and granular parts of the nucleoli segregate and the latter gradually disappear. At 14 hours, all nucleoli are reduced to their fibrillar parts that have the aspect of small dense bodies scattered in the nucleus. Simultaneously, the chromatin bodies begin to unite into a common network. This process continues at 16 hours (stage of pronuclei). The chromatin network is connected to the nuclear envelope via submembrane bodies of condensed chromatin tightly applied to the inner nuclear membrane. The macronuclear envelope has no coating of dense material in these areas. Thereafter (24 and 26 hours), areas of nuclear matrix free of the chromatin network appear in the macronucleus. At 28 and 34 hours, the chromatin network condenses and the residual nucleoli are caught in its meshes, being incorporated into the chromatin. The points of contact of the network with the nuclear envelope become less numerous.

Phylogenetic hypotheses proposed for extant genera of the Characeae by Wood & Imahori (1965) and by Khan & Sarma (1984) are based on morphological characters, and morphological characters and chromosome numbers respectively. For all six extant taxa, cladistic analyses have been performed on organismal characters and chromosome numbers, sequence data from the nucelar-encoded small subunit rRNA gene, and a combined morphological and molecular data set. These analyses support: 1) monophyly of the Characeae, 2) monophyly of tribe Chareae, 3) placement of Nitellopsis basal to the rest of the Chareae, and 4) monophyly of Lamprothamnium. Neither the Wood & Imahori nor the Khan & Sarma hypothesis is strongly supported. Additional analyses based on a more comprehensive taxon sampling may help resolve: 1) monophyly of Chara, 2) monophyly of Nitella, 3) monophyly of the Nitelleae, 4) placement of Nitella axillaris, and 5) placement of Lamprothamnium.

Heterokonta, Haptophyta and Cryptista are grouped together as the kingdom Chromista. As Heterokonta are considerably more diverse than the other two taxa, they have recently been raised in rank from phylum to infrakingdom, and subdivided into three phyla: the predominantly algal Ochrophyta (formerly subphylum Ochrista), and the purely heterotrophic Sagenista and Bigyra. The Sagenista comprise the classes Labyrinthulea (orders Thraustochytridiales and Labyrinthulales) and Bicoecea (bicoecids and the probably related flagellates Cafeteria and Pseudobodo, here designated anoecids and placed in the new order Anoecales). The Bigyra are characterised by a double ciliary transition helix and comprise three subphyla: Opalinata, which are all non-phagotrophic gut symbionts without peroxisomes (classes Proteromonadea and Opalinea; plus Blastocystis which lacks cilia and forms the basis for a recently established class Blastocystea); Pseudofungi, which are walled saprotrophs (classes Oomycetes and Hyphochytrea); and Bigyromonada (the phagotrophic zooflagellate DevelopayellaTong 1985, for which a new class Bigyromonadea, order Developayellales, and family Developayellaceae are created).

This paper discusses the phylogeny, systematics, and evolution of the Sagenista and Bigyra and the evidence that they, like non-photosynthetic ochrophytes, evolved from photosynthetic ancestors by the loss of plastids and periplastid membranes. As the Bigyra are closely related to the Ochrophyta, and may have evolved from them, the two phyla have been grouped together as a superphylum Gyrista. Sagenista appear to be the sister group of Gyrista.

The cells of euglenoid flagellates possess a peculiar structural complex located under the plasmalemma, known as the pellicular complex or pellicle. So far this structure has been investigated in a limited number of species; comparative aspects have been neglected. The present study is based on the following 14 Euglena strains, grown in the Collection of Photosynthetic Microorganisms of the Institute of Biological Research, Cluj-Napoca, or collected from different water bodies located near Cluj-Napoca (Romania): E acusEhr., E texta(Duj.) Hübner, E oxyurisSchmarda, E. viridisEhr., E. stellataMainx, E. geniculataDuj., E. tristellaChu, E. pisciformisKlebs, E. gracilisKlebs, E. splendensDang., E. polymorphaDang., E. sanguineaEhr., E. desesEhr. and E. mutabilisSchmitz. Species with a high degree of metaboly exhibit a narrower strip, a thinner membrane cytoskeleton, and the plate-like projections may be absent. Species with a low degree of metaboly or rigid ones possess broad, thick pellicular strips and long plate-like projections. Microtubules may be absent (e. g. E. texta). The present investigation has shown that the peripheral cytoskeleton of Euglena species is relatively homogeneous and based on the same structural model, which differs in various species in relation to the degree of metaboly.

The phylogeny of representative species of the apicomplexan order Haemosporina Danilewsky, 1885 was reconstructed by cladistic analysis. Life cycle and ultrastructural characters for members of the genera Plasmodium, Haemoproteus, Leucocytozoon, Hepatocystis, and Polychromophilus were assessed using Eimeria tenella as an outgroup. Each of these genera was monophyletic and a clade containing Haemoproteus, Hepatocystis, and Polychromophilus was the sister group to Plasmodium. There was no obvious correlation between the parasite phylogeny and that of the vertebrate hosts. There was however, a general agreement between the parasite phylogeny and that of the dipteran hosts. There was no pattern of strict cospeciation between parasites and these overall host groups, but there appears to be more evidence of coevolution of parasites with their vectors than with their vertebrate hosts. This correspondence is indicative of a more ancient parasite-vector association.