Ref ID : 2129
Wolfgang Petz and Wilhelm Foissner; Morphology and Morphogenesis of Lamtostyla edaphoni Berger and Foissner and Onychodromopsis flexilis Stokes, Two Hypotrichs (Protozoa: Ciliophora) from Antarctic Soils. Acta Protozoologica 35:257-280, 1996
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The morphology and morphogenesis of Lamtostyla edaphoni Berger and Foissner, 1987 and Onychodromopsis flexilis Stokes, 1887 were investigated using silver impregnation and scannig electorn microscopy. Stomatogenesis of L. edaphoni commences apokinetally near the leftmost transverse cirrus, like in L. perisincirra, L. hyalina and L. australis nov. comb. This distinguishes Lamtostyla from Amphisiella, whose oral primordium originates parakinetally from the amphisiellid median cirral row (ACR). Five cirral anlagen develop. In the proter, the undulating membranes, the buccal cirrus and the cirrus left of the ACR each provides one streak, two anlagen derive from the ACR. In the opisthe, the oral primordium produces the anlage for the undulating membranes and very likely three cirral streaks; one anlage develops at the posterior end of the ACR. The new ACR is formed by alignment of the two rightmost cirral anlagen, proving the Lamtostyla belongs to the Amphisiellidae. Based on these data, improved definitions are given for all amphisiellid genera. Onychodromopsis flexilis is redescribed emphasizing somatic variation and the fine structure of the oral apparatus. It has cortical granules and an oxytrichid FVT-cirral pattern but two to three right and one to two left marginal rows. The morphogenetic processes are very similar to those of Oxytricha granulifera. In the opisthe, cirrus IV/2, V/3 and V/4 each provides one streak (anlagen 4-6), and three streaks (anlagen 1-3) originate from the oral primordium and/or the posterior ends of anlagen 4-6. The anlagen of the proter originate from the paroral membrane, cirri II/2, III/2 and IV/3, and by splitting of the opisthe's anlagen 5 and 6. Two marginal anlagen each develop in the outer right and inner left marginal row; the inner right and outer left row remain unchanged and are later resorbed. Physiological regeneration resembles development in the proter. However, cirrus V/3 is inactive and the anlagen 5 and 6 originate from cirri IV/2 and V/4, respectively. The data show that O. flexilis belongs to the Oxytrichidae and is closely related to Oxytricha.