The Fine Structure of Nyctotherus cordiformis (Ehrenberg)

Abstract

SYNOPSIS. An electron‐microscopic investigation of gluaraldehyde‐and osmium‐vapor‐fixed Nyctotherus cordiformis has revealed the following: (1) A thin epiplasmic layer lies directly beneath a single limiting membrane. (2) The somatic kinetosomes are arranged in approximately 76 parallel rows separated from each other by a vacuolated region 2.4 μ wide. (3) The kinetosomes in each row are paired (both members ciliated), with 7 tubular fibrils (18‐21 mμ) originating radially from the right posterior margin of the posterior kinetosome, passing upward and anteriorly as a compact bundle. Also finding their origin in the proximity of the right radial fibrils point of origin are approximately 7 tubular fibrils, extending downward and posteriorly, where they join with adjacent posteriorly directed fibrils. Tangentially arranged tubular fibrils originate from the left anterior margin of both kinetosomes and are directed upward and anteriorly. Dense filamentous material surrounds both kinetosomes and extends laterally towards the adjacent rows. (4) Peculiar, electron‐dense, spherical bodies (10‐14 mμ) and larger rectangular bodies are present in the lumen of the kinetosomes. (5) A fine filamentous reticulum is present under the double row of kinetosomes of the UM as well as the 100 membranellar units of the AZM. (6) Oral fibrils (18 mμ) in groups of 3 extend upward into the ectoplasmic folds which separate the membranellar units; additional fibrils extend deep into the anterior and posterior ectoplasmic regions. (7) The nemadesmata originate on the right side of the buccal cavity and extend outward to their apparent terminus in the vacuolated ectoplasm. A brief historical account and results of light‐microscopical investigation employing silver impregnation methods are also included as well as a discussion of the anteriorly directed right radial fibrils, deep posterior fibrils and their non‐kinetodesmal affinities.

Phylogenetic study of Class Armophorea (Alveolata, Ciliophora) based on 18S-rDNA data

“…This also applies even to trees in which Armophorea is monophyletic, given the paraphyly of Metopidae (Figure 3). A diplostichomonad paroral, in which a ridge separates two rows of kinetosomes (Figure 8B) was found in C. medusula by Santa-Rosa (1975), thus matching this structure’s configuration in clevelandellids (Paulin, 1967; Puytorac and Grain, 1976; Takahashi and Imai, 1989; Grim, 1998), but also in the metopid Parametopidium circumlabens (Biggar & Wenrich, 1932) Aescht, 2001 (Silva-Neto, 1993). However, this possibly differs from the seemingly linearly arranged oral dikinetids in Metopus (Esteban et al , 1995; Foissner and Agatha, 1999; Lynn, 2008).…”

Fine Structure and Molecular Phylogeny of Parametopidium circumlabens (Ciliophora: Armophorea), Endocommensal of Sea Urchins

“…In P. circumlabens , the paroral is diplostichomonad, which is similar to clevelandellids and Caenomorpha (de Puytorac and Grain ; Paulin ; Santa‐Rosa in da Silva Paiva et al. ).…”

“…; Çapar ; Foissner and Agatha ). Clevelandellids have somatic dikinetids with both kinetosomes ciliated (de Puytorac and Grain ; de Puytorac and Otkem ; Fernández‐Galiano ; Grim ; Paulin ), while Caenomorpha Perty representing armophorids, has meridian kinetids (i.e. “bell” kineties) with all kinetosomes ciliated and dikinetids of perizonal stripe with only posterior kinetosomes ciliated, thus both cases differ from P. circumlabens (Santa‐Rosa in da Silva Paiva et al.…”

“…Those microtubules are also present in clevelandellids Nyctotherus and Sicuophora (King et al. ; Paulin ; Puytorac and Grain ), but also in some heterotrichs (e.g. Ishida et al.…”

Morphogenesis and Cortical Ultrastructure of Brooklynella hostilis, a Dysteriid Ciliate Ectoparasitic on Marine Fishes*

“…Cyrtophorine ciliates, we postulate in accord with others, are an assemblage of forms in which the evolutionary process started to test prototypes of buccal ciliature and morphogenesis which were later accomplished and developed in the so-called "more advanced" ciliate groups. In our relatively simple type of "hypostomatid" ciliate, 42. The secretory furrow surrounded by closely packed secretory vesicles.…”