Gabriela Cristina Küppers

An Antarctic hypotrichous ciliate, Parasterkiella thompsoni (Foissner) nov. gen., nov. comb., recorded in Argentinean peat-bogs: morphology, morphogenesis, and molecular phylogeny.

The ciliate Parasterkiella thompsoni (Foissner, 1996) nov. gen., nov. comb. was originally described from Antarctica. In the present study, we report the morphology, morphogenesis during cell division, and molecular phylogeny inferred from the 18S-rDNA sequence of a population isolated from the Rancho Hambre peat bog, Tierra del Fuego Province (Argentina). The study is based on live and protargol-impregnated specimens. Molecular phylogeny was inferred from trees constructed by means of the maximum parsimony, neighbor joining, and Bayesian analyses. The interphase morphology matches the original description of the species. During the cell division, stomatogenesis begins with the de novo proliferation of two fields of basal bodies, each one left of the postoral ventral cirri and of transverse cirri, which later unify. Primordia IV-VI of the proter develop from disaggregation of cirrus IV/3, while primordium IV of the opisthe develops from cirrus IV/2 and primordia V and VI from cirrus V/4. Dorsal morphogenesis occurs in the Urosomoida pattern-that is, the fragmentation of kinety 3 is lacking. Three macronuclear nodules are generated before cytokinesis. Phylogenetic analyses consistently placed P. thompsoni within the stylonychines. New data on the morphogenesis of the dorsal ciliature justifies the transference of Sterkiella thompsoni to a new genus Parasterkiella.

Morphology of Clapsiella magnifica gen. n., sp. n., a new hypotrichous ciliate with a curious dorsal ciliary pattern.

The present work describes the morphology and infraciliature of a new hypotrichous ciliate, Clapsiella magnifica gen. n., sp. n., found in rewetted soil from a temporal pond in Argentina. It was studied by means of live observation and protargol impregnation. Its main diagnostic features are: Flexible hypotrich measuring 250-320 μm × 70-140 μm in vivo; two macronuclear nodules and 4-6 micronuclei. Single contractile vacuole. Cytoplasm transparent, cortical granules absent. Somatic ciliature composed of a tricorona of cirri, three buccal(?) cirri, 6-9 ventral rows, 3-5 right marginal(?) rows, one left marginal row, and 12-17 transverse cirri. Dorsal pattern rather complicated, with about 14 kineties and kinety fragments, with scattered kinetids among them; 17-28 caudal cirri arranged in three rows on dorsal kineties 1, 3, and 7. Remarkably, dorsal kinetids have two or four basal bodies, bearing a stiff bristle arising from left anterior basal body. Adoral zone composed of 70-92 membranelles, occupying about 40% of body length in protargol preparations; paroral and endoral curved, resembling a cyrtohymenid pattern. The peculiar dorsal ciliary arrangement and the unique combination of other characters require the establishment of a new genus for this new species, which is considered incertae sedis in the Hypotricha but possibly related to the oxytrichids.

Pelagostrobilidium wilberti n. sp. (Oligotrichea, Choreotrichida): Morphology and Morphogenesis

ABSTRACT. Morphology, infraciliature, morphogenetic features, and some ecological data for Pelagostrobilidium wilberti n. sp. are described. This new species was collected from a temporary pond in Magdalena, Buenos Aires province, Argentina, which was sampled monthly from August 2003 to July 2005. The species was found in autumn and winter. Observations were made in vivo and after staining with protargol. Pelagostrobilidium wilberti n. sp. measures 63–84 × 42–49 μm in vivo and is conical in shape, with a posterior spine‐like cytoplasmic process. It possesses 6 somatic kineties, with kinety 2 sinistrally curved and shorter than the others. The oral apparatus is composed of 25–32 external and two internal membranelles. The macronucleus is horseshoe‐shaped and located beneath the oral apparatus; two or three spherical micronuclei lie dorsally. There is a posterior contractile vacuole. Morphogenesis is hypo‐apokinetal and begins dorsally between the curved kinety 2 and kinety 3. After the discovery of this new species, the diagnosis of the genus Pelagostrobilidium was amended.

Ciliates from eutrophized water in the northern Brazil and morphology of Cristigera hammeri Wilbert, 1986 (Ciliophora, Scuticociliatia)

Ciliates occur in all major aquatic and soil environments worldwide and are important links in the microbial food webs, which, along with other free-living protists, are generally overlooked in biodiversity conservation programs. In Brazil, the northern region comprises the Brazilian Amazonia, an area widely known for its huge biodiversity. However, the diversity of ciliates in that region is still almost unknown. As result of the present study, a total of 21 species of ciliates, distributed among 15 genera, were inventoried from samples of eutrophized water collected in the city of Belém, capital of the state of Pará, one of the states which comprise the Brazilian Amazonia. In addition, a local population of the rare scuticociliate Cristigera hammeri is described from optical and electron microscopy observations, and its synonymy with C. pleuronemoides is rejected based on new evidence.

Morphology and Notes on Morphogenesis during Cell Division of Deviata polycirrata n. sp. and of Deviata bacilliformis (Gelei, 1954) Eigner, 1995 (Ciliophora: Kahliellidae) from Argentina

ABSTRACT. Described herein are the morphology and certain morphogenetic stages of a new freshwater ciliate species, Deviata polycirrata n. sp., and of Deviata bacilliformis recorded in the soil of a dried temporary pond from Argentina. Ciliates were studied alive and after silver impregnation with Protargol. Deviata polycirrata n. sp. measures 130–180 × 45–70 μm in vivo. The species possesses 8–9 long cirral rows on the right and 9–13 on the left of the oral zone, and 3 dorsal rows of dikinetids. The adoral zone is composed of 39–48 membranelles. There are four macronuclear nodules and usually two micronuclei. A single contractile vacuole is located equatorially on the left body margin. This new species mainly differs from its congeners in having a higher number of cirral rows, the three long dorsal rows of dikinetids (vs. usually one to two dorsal rows of dikinetids), and a higher number of adoral membranelles. The other species reported here, D. bacilliformis, is recorded for the first time in Argentina. Unlike previous observations on this species, on the dorsal surface there are cirral rows that are preceded by cilia (combined cirral rows), and stomatogenesis begins with the proliferation of non‐ciliferous basal bodies some distance posterior to the buccal vertex.

Description of Deviata rositae n. sp., a new ciliate species (Ciliophora, Stichotrichia) from Argentina

ABSTRACT. Soil samples were taken from a temporary pond located in Buenos Aires province, Argentina, during the dry phase in the summer of 2005. The ciliates were studied alive and after staining with protargol. Deviata rositae n. sp. measures 112–154 μm in length and 21–28 μm in width in vivo and has a vermiform body. The contractile vacuole is located in the mid‐body on the left. The macronucleus is moniliform and there are 1–3 micronuclei. The oral apparatus is composed of 14–18 adoral membranelles and straight paroral and endoral membranes that never intersect each other. The somatic ciliature is arranged in four frontal cirri, one buccal cirrus, six long and slightly spiraled rows of cirri with the first right row extending up to the equatorial or sub‐equatorial region, and two dorsal rows of dikinetids. This new species of Deviata primarily differs from its congeners by the number of macronuclear nodules and the number and disposition of the dorsal rows of dikinetids.

Discomorphella pedroeneasi sp. nov. (Ciliophora, Odontostomatida): An anaerobic ciliate hosting multiple cytoplasmic and macronuclear endocytobionts

Odontostomatids are among the less studied representatives of the Ciliophora. They are anaerobic microeukaryotes usually occurring as rare species in sapropelic environments. Here we describe a novel species of Discomorphella, named Discomorphella pedroeneasi sp. nov., using light and electron microscopy observations. Discomorphella pedroeneasi displays many complex morphological features, for which new terms are introduced, such as the auricules, epistomial fringe spacer, frontal awning, odontostomatid ciliary sockets, oral lips and ventral flap. Remarkably, D. pedroeneasi has at least six types of endocytobionts, including intramacronuclear ones, and organelles ultrastructurally similar to the M/H bodies of the odontostomatid Saprodinium dentatum. Based on the new data and revision of the literature, we propose two new diagnostic characters for species separation within Discomorphella: the fringe spacer ratio and the posterior fringe ratio. The taxonomy of Discomorphella is revised and an identification key is provided.

Ontogeny and Molecular Phylogeny of Apoamphisiella vernalis Reveal Unclear Separation between Genera Apoamphisiella and Paraurostyla (Protozoa, Ciliophora, Hypotricha).

Morphology and divisional morphogenesis of the hypotrich ciliate Apoamphisiella vernalis are investigated based on two populations from Brazil. Typical specimens of A. vernalis replicates its ventral ciliature from six fronto-ventral-transverse (FVT) anlagen independently formed for proter and opisthe, plus one or more short anlagen located between IV and V, which form surplus transverse cirri. Dorsal morphogenesis occurs as in typical oxytrichid dorsomarginalians, viz., with formation of three anlagen and fragmentation of the rightmost one. Dorsomarginal kineties are formed near anterior end of right marginal cirral row anlagen. Various anomalous specimens exhibiting more than two long ventral rows were found, which are explained by increasing the number of FVT anlagen and/or the number of cirri produced by anlagen. Comparative ontogeny and phylogenetic analyses based on the 18S rDNA reveal that Apoamphisiella vernalis is closely affine to North American and European strains of the Paraurostyla weissei complex. Their reduced genetic distances and conspicuous morphological variability show that both genera can overlap, which implies the necessity of re-evaluating the contextual relevance of some morphological characters commonly used for genus-level separation within hypotrich taxa.