Morphology, ontogenesis and molecular phylogeny of a new saline soil ciliate, Uroleptoides salina nov. spec. (Ciliophora, Hypotrichia)

The morphology, morphogenesis and molecular phylogeny of a new saline soil hypotrich ciliate, Uroleptoides salina nov. spec., discovered from China, was investigated. The new species is characterized as follows: body 150-215 × 40-50 μm in vivo, slender and highly flexible; usually four ellipsoidal macronuclear nodules; contractile vacuole absent; cortical granules absent; endosymbiotic algae present; amphisiellid median cirral row consists of 14-25 cirri and terminates about 47% down length of body; usually three buccal cirri and 3-13 cirri left of anterior portion of amphisiellid median cirral row; 3-5 transverse cirri. Morphogenesis during binary fission is characterized by: (1) the parental adoral zone of membranelles is retained completely, parental paroral contributes to the formation of the undulating membranes anlage for the proter; (2) the oral primordium of the opisthe is formed apokinetally; and (3) the amphisiellid median cirral row is formed from two anlagen. Phylogenetic analyses based on SSU rDNA sequence data show that Uroleptoides salina nov. spec. has a close relationship with its morphologically similar species, U. longiseries, U. magnigranulosus, Orthamphisiella breviseries, and Parabistichella variabilis.

High cryptic soil ciliate (Ciliophora, Hypotrichida) diversity in Australia

The diversity and distribution of soil ciliates from Australia is poorly known. Thus, we studied eight taxa, using the non-flooded Petri dish culture method, live observation, silver impregnation, detailed morphometrics, ontogenesis, and reinvestigation of type slides. At first glance, the Australian taxa looked very similar to described species, however, detailed investigations resulted in the identification of six cryptic species: Afroamphisiella multinucleata minima nov. subspec., Cladotricha similis nov. spec., Erimophrya similis nov. spec., Heterogonostomum salinarum nov. gen., nov. spec., Pseudohemisincirra arabica australiensis nov. subspec., and Pattersoniella (Pattersoniellides) australiensis nov. subgen., nov. spec. This new subgenus is unique among all described hypotrichs in having reduced some anterior paroral dikinetids the fibrillar associates of which are, however, still present. Only two of the eight taxa are possibly cosmopolitans: Apourosomoida halophilaFoissner et al., 2002 and Urosoma karinaeFoissner, 1987. This supports the moderate endemicity model, i.e., that a third of protists have a restricted distribution (Foissner, Chao and Katz 2008).

Molecular phylogeny and ontogeny of a new ciliate genus, Paracladotricha salina n. g., n. sp. (Ciliophora, Hypotrichia)

A hypotrichous ciliate, Paracladotricha salina n. g., n. sp., was discovered in hypersaline waters (salinity about 80‰) from Qingdao, China. Its morphology and some major ontogenetic stages were studied and the phylogenetic position was estimated using standard methods. Paracladotricha salina is characterized by a flexible, more or less slender body (size 50-120 × 20-35 μm), a gonostomatid oral apparatus, one short and two long frontoventral rows, four macronuclear nodules, almost completely reduced dorsal kineties 1-3, and a loss of several parts of the ciliature, namely, the slightly shortened ciliary row of the adoral membranelles, the paroral, and the buccal, the postoral and pretransverse ventral, the transverse, and the caudal cirri. The ontogenesis is rather simple: anlage II of both filial products and anlage III of the opisthe originate de novo, while anlagen IV and V are formed within the parental rows. This combination of features requires the establishment of a new genus, Paracladotricha, which is, according to the morphological data, closely related to Schmidingerothrix and Cladotricha. The small-subunit rRNA gene was sequenced, indicating that P. salina is, as also demonstrated by the oral apparatus, a member of the gonostomatids. We provide a first, vague hypothesis about the phylogenetic relationships of the Gonostomatidae, Cladotrichidae, and Schmidingerotrichidae. However, since molecular data of the type species of these higher taxa are lacking, their validity and relationships remain obscure.

Different stop codon usage in two pseudohypotrich ciliates

Based on rRNA phylogeny, morphologic and morphogenetic characters, two major groups of hypotrich ciliates can be distinguished: euhypotrichs and pseudohypotrichs. Through the sequencing of actin genes, we show here that, interestingly, the pseudohypotrichs Dyophrys sp. and Euplotes vannus have a different stop codon usage. In fact, the stop codon usage of the former species resembles that of euhypotrichs. This unexpected result is used to discuss the origin and acquisition of genetic code deviations in ciliates.

Divisional morphogenesis in Uroleptus caudatus (Stokes, 1886), and the relationship between the Urostylidae and the Parakahliellidae, Oxytrichidae, and Orthoamphisiellidae on the basis of morphogenetic processes (Ciliophora, Hypotrichida)

Morphogenetic processes during division in Uroleptus caudatus (Stokes, 1886) are described using protargol impregnation. As is typical for the family Urostylidae Bütschli, 1889, zigzag midventral cirri develop, but contrary to most species of this family the adoral membranelles of the proter are not renewed during division and two dorsomarginal kineties develop. These two atypical features occur in only two other species of the Urostylidae (Uroleptus musculus, Holosticha diademata), and in all species of the family Parakahliellidae Eigner. 1997, and in many of the Oxytrichidae Ehrenberg, 1838. Membranelles are also not renewed in the Orthoamphisiellidae Eigner, 1997. This shows that these three atypical members of the family Urostylidae are those which are most closely related to the other three hypotrichous families named above. The highly distinct zigzag midventral cirri clearly separate the family Urostylidae from the other three hypotrichous families. These cirri are used together with new morphogenetic features for a revised family diagnosis. The analysis of the Urostylidae revealed that during division all species of the family Urostylidae develop their cirral patterns, including the two rightmost ventral anlagen, in separate areas for each proter and opisthe. Thus, "long primary primordia" are absent in the Urostylidae. This is similar to the morphogenetic pattern by which the family Parakahliellidae is defined ("neokinetal 1") indicating that the Urostylidae are more closely related to the Parakahliellidae than to either the Oxytrichidae or to the Orthoamphisiellidae. All 68 detailed descriptions of divisional morphogenesis in species of the Hypotrichida are analyzed now in this and two former papers. As a result all these species can be assigned or at least recognized to be closely related to one of the following four families: to the Orthoamphisiellidae ("within-row" anlagen), to the Oxytrichidae ("neokinetal 3" anlagen), to the Parakahliellidae ("neokinetal 1" anlagen), and to the distinctly different Urostylidae ("midventral" anlagen). Thus, all Hypotrichida can most probably be assigned after morphogenetic investigation to one of the four families.

Redescription of Phacodinium metchnikoffi (Ciliophora, Hypotrichida): general morphology and taxonomic position

Living and stained specimens of Phacodinium metchnikoffi, collected near Madrid, Spain, were studied under light microscopy. Infraciliature was stained using a silver-impregnation procedure. The somatic infraciliature is composed of a relatively small number of discontinuous kinetics, formed by groups of few kinetosomes (pallets). The buccal ciliature is composed of an adoral zone of membranelles and a paroral formation otherwise unknown in ciliates, with many short kineties, which lie on a rigid stem. We propose that P. metchnikoffi is a primitive hypotrich and, consequently, we present a new classification system for hypotrichs.