Light and Electron Microscopical Observations on the Stomatogenesis of the Ciliate Coleps amphacanthus Ehrenberg, 1833

Abstract

Light and electron microscopical observations on the stomatogenesis of Coleps amphacanthus Ehrenberg, 1833, show that this “gymno”‐stome ciliate has a well developed oral ciliature made of 19–23 “paroral dikinetids” and three “adoral organelles.” These structures were previously known as “circumoral ciliature” and “dorsal brosse,” and it was thought that they originated from the distal ends of all the 22–26 somatic kineties. Contrary to this view, only four stomatogenic kineties (K1, Kn, Kn‐1, and Kn‐2) are involved in stomatogenesis of the opisthe. All paroral dikinetids arise from one single kinetofragment (KF1) to the right of the oral anlage while the adoral organelles originate from the three left kinetofragments (KFn, KFn‐1, and KFn‐2). In particular, the future paroral dikinetids perform a complex morphogenetic movement that leads to a situation where the postciliary microtubules of the once posterior kinetosome of each oral dikinetid give rise to the cytopharyngeal microtubular ribbons. The postciliary origin of the cytopharyngeal ribbons which could only be detected by an EM study of stomatogenesis shows that the basket of Coleps belongs to the cyrtos‐type and not to the rhabdos‐type basket, where transverse microtubules accompany the basket‐forming nematodesmata. The taxonomic implications of these observations, which may lead to a revision of the systematic position of the genus Coleps, are discussed.

Molecular phylogeny of ciliates: What does it tell us about the evolution of the cytoskeleton and of developmental strategies?

“…This result is in remarkable agreement with the morphogenetic analysis of Huttenlauch and Bardele [1987].…”

“…Coleps, previously thought to be a "simple" primitive ciliate ("gymnostome"), clearly groups with the oligohymenophorans. This result is in remarkable agreement with the morphogenetic analysis of Huttenlauch and Bardele [1987]. 5.…”

Phylogenetic Relationships between Prostome and Colpodean Ciliates Tested by Small Subunit rRNA Sequences

“…For example, after using both light and electron microscopy, Bardele et al (1991) transferred the sorocarp-forming ciliate Sorogena stoianovitchae from the prostomes to the class Colpodea. Huttenlauch and Bardele (1987) used these techniques to transfer the genus Coleps from the subphylum Rhabdophora to the subphylum Cyrtophora sensu Small (1976). However, the phylogenetic relationships between the different classes remain mostly unresolved with this approach.…”

Morphology and Gene Sequence of Levicoleps biwae n. gen., n. sp. (Ciliophora, Prostomatida), a Proposed Endemic from the Ancient Lake Biwa, Japan

“…Family Colepidae. The Colepidae Ehrenberg, 1838 include ciliates with a calcified armour and a prostome ciliary organization (Corliss 1979;Foissner 1984;Foissner et al 1994Foissner et al , 1999Huttenlauch 1986Huttenlauch , 1987Huttenlauch and Bardele 1987;Kahl 1930;Small and Lynn 1985;Wilbert and Schmall 1976). Although details vary considerably, the basic organization is the same in all genera and species (Fig.…”

“…The colepid terminology, which is rather confused and shown in Fig. 1-3, is based on Kahl (1930) and Huttenlauch and Bardele (1987). Of particular importance is the number of armour tiers: frequently, only those that can be easily seen are counted, while the circumoral and caudal tiers are neglected.…”