Archiv für Protistenkunde最新文献

Light and electron microscopical observations have been made on the gonyaulacoid dinoflagellate Protoceratium reficulatum (Claparède et Lachmann) Bütschli collected close to the type locality of Protoceratium acerosBergh, the type species of Protoceratium. Analysis of plate tabulation shows agreement with Gonyaulax grindleyiREINECKE and supports conspecificity between P. reticulatum, P. aceros and G. grindleyi, the first name having priority. The ultrastructure includes a branched chloroplast and a centrally located pyrenoid complex. The pusular system consists of one or two sac pusules associated with the flagellar canals. The three-dimensional arrangement of the flagellar apparatus is basically similar to that of other dinoflagellates except for the presence of a single microtubular root associated with the longitudinal basal body. Each flagellar canal is surrounded by a distinct striated fibrous collar. The collars are interconnected by two striated connectives. The plate tabulation and fine structure of Protoceratium reficulatum indicate close relationship to the genus Gonyaulax, with minor differences in plate tabulation and fine structure. It is suggested to maintain the genus Protoceratium until the fine structural diversity with Gonyaulax is better known.

Clonal cultures from Scenedesmus acuminatus (Lagerh.) Chod. and Scenedesmus pectinatusMeyen were studied in regard to the variability of coenobia by an intensive cultivation using nutritional medium with different NaCl concentrations. With an increasing salinity of the medium in the clonal cultures from both species, coenobia corresponding to Scenedesmus regularis SVIR. were found. Concrete conclusions for changeability of characteristics concerning the taxonomic status of S. acuminatus (Lagerh.) Chod. and S. pectinatusMeven are drawn.

We have sequenced the 18S rRNA genes of six sarcomonad flagellates from the orders Cercomonadida (Heteromita globosa and four Cercomonas species) and Thaumatomonadida (Thaumatomonas sp.). Phylogenetic analysis by maximum likelihood; parsimony and two distance methods shows that these two orders are related, supporting their classification in a revised class Sarcomonadea. Molecular divergence within Cercomonas is huge: as great as among all fungi or land plants. Heteromita, Thaumatomonas and euglyphid testate amoebae all apparently evolved from Cercomonas-like ancestors. Euglyphids and thaumatomonads, which both bear silicious scales, are more closely interrelated than are some species of Cercomonas. The Glade comprising sarcomonads and Testaceafilosia is a sister to the amoeboflagellate chlorarachnean algae. Our trees robustly show that sarcomonads, euglyphids, and Chlorarachnea are together specifically related to Plasmodiophora, previously classified in the opalozoan class Phytomyxea: these taxa are now all included in a revised phylum Rhizopoda. Phylogenetic analysis of rRNA sequences representing all major lineages of neokaryotes (i.e. eukaryotes branching above Euglenozoa on molecular trees) shows that Rhizopoda are one of thirteen major neokaryote Glades and are phylogenetically distinct from lobose amoebae (subphylum Lobosa of the phylum Amoebozoa). Rhizopoda may be one of the earliest diverging megakaryote Glades.

Two new species of marine amoebae, isolated from the Sound (Denmark) are described. Comparison of Korotnevella nivo n. sp. with other known species of this genus indicated that it is difficult to use the structure of surface scales in Paramoebidae as a taxonomic character. One of the characteristic features of Hartmannella lobifera n. sp. is its remarkable cyst structure.

Recent molecular and ultrastructural discoveries necessitate major changes in the higher level classification of the kingdom Protozoa. A new class Anaeromonadea and subphylum Anaeromonada are created for the anaerobic tetrakont flagellate Trimastix, which is grouped with Parabasala, ranked as a subphylum, to form the new protozoan phylum Trichozoa. To simplify the supraphyletic classification of Protozoa I dispense with the category parvkingdom by increasing Neozoa in rank from infrakingdom to subkingdom and creating a new subkingdom Eozoa for the eokaryote phyla Trichozoa, Percolozoa and Euglenozoa.

The subkingdom Neozoa, containing all neokaryote Protozoa, is divided into four infrakingdoms: Sarcodina infrak. nov.; Alveolata Cavalier-Smith 1991; Actinopoda Calkins 1902, stat. nov.; and Neomonada infrak. nov. Sarcodina are subdivided into three superphyla: Eosarcodina superph. nov. (phyla Reticulosa and Mycetozoa); Neosarcodina (phyla Amoebozoa and Rhizopoda); and Haplosporidia (phylum Haplosporidia). Paramyxia are treated as a superclass within infraphylum Sporozoa of the Apicomplexa, not as a separate phylum.

Major changes are made to the tubulicristate phylum Opalozoa: I transfer the partially pseudopodial opalozoan groups into Rhizopoda; I move Proteromonadida into the subphylum Opalinata, and group the remaining non-opalinate opalozoans with the Choanozoa as a new zooflagellate phylum Neomonada, leaving only the revised Opalinata in the Opalozoa; these residual Opalozoa are left as protists incertae sedis, as it is unclear whether they belong in the kingdom Protozoa or Chromista. Neomonada are divided into four subphyla: Choanozoa stat. nov. (classes Choanoflagellea, Coral lochytrea); Hemimastigophora; Apusozoa subphyl. nov. (classes Thecomonadea, Anisomonadea, Jacobea cl. nov., Ebridea) and Isomita subphyl. nov. (classes Telonemea and Cyathobodonea).

Commation is transferred from Heterokonta to Apusozoa. Three apusozoan orders (Discocelida; Caecitellida; and Commatiida) are created. Within the revised Rhizopoda I group Sarcomonadea (revised by excluding proteomyxids and Jakoba) and Filosea together as a new subphylum Monadofilosa, and group Chlorarachnea with the formerly opalozoan class Proteomyxidea as a second new rhizopod subphylum, Reticulofilosa; Phytomyxea are removed from Opalozoa and treated as a third new rhizopod subphylum, Phytomyxa.

Lobose amoebae are excluded from Rhizopoda and placed in the separate sarcodine phylum Amoebozoa as a subphylum (Lobosa) comprising the classes Amoebaea and Testacealobosea. A new amoebozoan subphylum (Holomastiga) and class (Holomastigea) are created for Multicilia, and Archamoebae (classes Pelobiontea and Entamoebea) are treated as a third subphylum of Amoebozoa.

A central role for amoeboflagellates in eukaryote cell evolution is proposed. I suggest that ancestral eukaryotes were non-amoeboid zoofl