Morphological, Biometric, and Morphogenetic Comparison of Two Closely Related Species, Stylonychia vorax and S. pustulata (Ciliophora: Oxytrichidae)1

Abstract

Differences in the morphology of Stylonychia vorax Stokes, 1885 and S. pustulata (Müller, 1786) Ehrenberg, 1838 recognizable in vivo are the shape, the ventral cirral pattern, the caudal cirri, and the mode of moving. The dorsal‐bristle complexes are distinguishable by the length of dorsal kinety four and the spaces among the pairs of basal bodies. When the ranges of variation of different populations and clones are compared by biometric analyses, S. vorax shows a relatively stable cortical pattern whereas in S. pustulata the cortical elements are regulated depending on the size of the body and the number of adoral membranelles. In S. vorax morphogenesis begins with a proliferation of basal bodies close to the transverse cirri. In contrast, in S. pustulata, the oral primordium appears de novo between the left marginal row and the postoral cirri. All other morphogenetic events are the same for both species. In proters and opisthes the six anlagen of the frontal‐ventral‐transverse cirri are of different origin and evolve independently. Three anlagen of the opisthe separate from the oral primordium, two originate from the right, and one from the left postoral cirrus. Three anlagen of the proter evolve from the posteriormost cirrus in the frontal area, one from the parental undulating membranes, one from the buccal cirrus, and one from the cirrus below the buccal cirrus. The anlagen one to six generate one, three, three, three, four, and four cirri. The characteristic arrangement of the undulating membranes and the participation of only two postoral cirri in the formation of primordia provide features that distinguish between the often confused genera Oxytricha and Stylonychia.

Taxonomic and nomenclatural revision of Sl�de?ek's list of ciliates (Protozoa: Ciliophora) as indicators of water quality

“…Sladecek et al (1981) and Wegl (1983) give different saprobic valencies (-6 4 --; -2 6 2 -) . Wirnsberger et al (1985a) . Sladecek et al (1981) and Wegl (1983) give different saprobic valencies for S. pustulata and S. notophora (--10 --; --7 3 -) .…”

Taxonomic resolution of Stylonychia notophora (Alveolata, Ciliophora, Hypotricha) sensu Sapra and Dass 1970 using an integrative approach

“…Sapra and Dass isolated cells of Stylonychia from the Okhla region (Delhi) of the River Yamuna [9] (OK site in the present study), which they identified as Stylonychia notophora Stokes, 1885 [5]. Subsequently, several authors also suggested that this was a misidentification and was a population of T. pustulata (Müller, 1786) Ehrenberg, 1835 [3,10,11].…”

“…In the present study, morphological, morphogenetic and molecular data for six populations nominally identified as S. notophora sensu Sapra and Dass, 1970 were analysed for intra-clonal and inter-population variations. Using this integrative approach, comparisons between S. notophora sensu Sapra and Dass, 1970 [9] and T. pustulata [11] confirm that these taxa are identical. Therefore, S. notophora sensu Sapra and Dass, 1970 is a misidentification and is, in fact an Indian population of T. pustulata.…”

“…Sapra and Dass [9] isolated a species of Stylonychia from the stretch of the River Yamuna traversing Delhi, India, and identified it as S. notophora Stokes, 1885 [5]. Several authors stated that the Indian population of S. notophora sensu Sapra and Dass, 1970 is synonymous with T. pustulata (Müller, 1786) Ehrenberg, 1835, now the type species of Tetmemena Eigner, 1999 [3,[10][11][12]. However, due to lack of sufficient data for the Indian population, this remained unconfirmed.…”

Physiological reorganization in the hypotrich ciliate Apoamphisiella vernalis (Protista, Ciliophora, Hypotricha)

“…In both cases, the oral primordium is curved rightwards and originates de novo [vs. originates adjacently (parakinetal?) to postperistomal cirri row in the European P. weissei (Wirnsberger et al, 1985)]; the undulating membranes start disaggregation before fusing; about half of the membranelles of the lapel are replaced; and the two rightmost FVT primordia originate from a primordium growing within the rightmost ventral row, which then splits in two.…”