Wilhelm Foissner

The morphology and morphogenesis of a new Australian metopid ciliate, Lepidometopus platycephalus nov. gen., nov. spec., were studied using live observation, various silver impregnation methods, scanning electron microscopy, and morphometry. The new genus is outstanding in having epicortical scales (lepidosomes) and a strongly flattened and distinctly projecting preoral dome. Diagnostic features of L. platycephalus include a small, reniform body carrying an elongated caudal cilium, about 11 ciliary rows, and an adoral zone composed of an average of 11 polykinetids. The morphogenesis of L. platycephalus matches data from other metopids in that (1) the body is drastically re-shaped, (2) the parental oral structures are reorganized but do not contribute to the daughter oral ciliature, (3) the opisthe’s adoral polykinetids originate pleurotelokinetally, (4) the opisthe’s paroral membrane is formed via re-arrangement of the posterior portion of the first two perizonal rows, and (5) the opisthe’s perizonal stripe is made by three parental perizonal rows and two dorsolateral ciliary rows. The morphogenetic data corroborate phylogenetic analyses in that caenomorphids are only superficially similar to metopids; metopids and clevelandellids are closely related; and litostomateans are the best candidates for a sister group of the metopid-clevelandellid assemblage within the SAL superclade.

We investigated the status of various Neokeronopsis populations, using protargol-impregnated type material, a new Chinese population, and literature data. This resulted not only in the recognition of a new species, Neokeronopsis asiatica, but also in upgrading Afrokeronopsis from subgenus to genus level. The genera Neokeronopsis and Afrokeronopsis differ mainly in the buccal depression (absent vs. present) and in the midventral cirri between proter and opisthe, which are either retained (Afrokeronopsis) or transformed into cirral anlagen (Neokeronopsis). Neokeronopsis asiatica nov. spec. differs from N. spectabilis (Kahl, 1932) by the following features: body size (~ 300 × 120 μm vs. 400 × 170 μm); posterior body end (acute with distinct indentation at site of caudal cirri vs. broadly rounded and without or indistinct indentation); posterior end of marginal rows (ending at different vs. same or similar level); dorsal kinety 1 (continuous vs. fragmented); and the size of the bases of the adoral membranelles (largest membranelles on average 18 μm vs. 29 μm wide). Improved diagnoses are provided for the family Neokeronopsidae and the genera contained therein, viz., Neokeronopsis, Afrokeronopsis, and Pattersoniella. Our study shows the importance of depositing type and voucher material in recognized repositories. Only this will allow future researchers to restudy the populations, for the sake of improved taxonomic and biogeographic knowledge.

Mitochondrial SSU-rDNA has been used recently to infer phylogenetic relationships among a few ciliates. Here, this locus is compared with nuclear SSU-rDNA for uncovering the deepest nodes in the ciliate tree of life using broad taxon sampling. Nuclear and mitochondrial SSU-rDNA reveal the same relationships for nodes well-supported in previously-published nuclear SSU-rDNA studies, although support for many nodes in the mitochondrial SSU-rDNA tree are low. Mitochondrial SSU-rDNA infers a monophyletic Colpodea with high node support only from Bayesian inference, and in the concatenated tree (nuclear plus mitochondrial SSU-rDNA) monophyly of the Colpodea is supported with moderate to high node support from maximum likelihood and Bayesian inference. In the monophyletic Phyllopharyngea, the Suctoria is inferred to be sister to the Cyrtophora in the mitochondrial, nuclear, and concatenated SSU-rDNA trees with moderate to high node support from maximum likelihood and Bayesian inference. Together these data point to the power of adding mitochondrial SSU-rDNA as a standard locus for ciliate molecular phylogenetic inferences.

Using standard morphological methods, we describe two new Leptopharynx species, each discovered in a specific biogeographic region and habitat. Leptopharynx bromeliophilus nov. spec., a minute species (25 × 20 μm) discovered in tanks of bromeliads from Jamaica, is small-mouthed and has a slightly concave preoral region, an average of 27 basal bodies in kinety 4, and a total of 142 basal bodies on average. Leptopharynx australiensis nov. spec., a comparatively large species (40 × 25 μm) discovered in jungle soil of Australia, is large-mouthed and has a distinctly oblique preoral region, widely spaced kinetids in kinety 1, a total of 184 basal bodies on average, and the oral primordium is inside of a cortical fold thus appearing right of the posterior end of kinety 1. Four new features are recognized for distinguishing Leptopharynx species: (1) to have a monomorphic (producing either small- or large-mouthed cells) or polymorphic (producing microstomes and macrostomes) life cycle; (2) the spacing of the kinetids in kinety 1 as either ordinary or wide; (3) the shape (flat or concave) and angle (≤ 15° slightly oblique, ≥ 40° distinctly oblique) of the preoral region; and (4) the total number of basal bodies, which has proven statistically.

There is a widespread belief that spathidiids have few morphological features. In contrast, we show a rich morphological diversity in five new species discovered in tank bromeliads from the Caribbean, using live observation; protargol impregnation; morphometry; scanning electron microscopy; and resting cyst morphology, demonstrating lepidosomes (organic scales) for the first time in spathidiid haptoria. Arcuospathidium bromelicola nov. spec. is very similar to the previously described A. muscorum but its resting cyst has conspicuous, pillar-shaped lepidosomes on the surface. Protospathidium lepidosomatum nov. spec. is very similar to the previously described P. muscicola but has outstanding, nipple-shaped (vs. conical) lepidosomes on the cyst surface. Spathidium bromeliophilum nov. spec., whose ontogenesis is highly similar to that of S. turgitorum, differs from similar species by the body length:width ratio, the number of ciliary rows, the shape of the oral bulge, and details of the ciliary pattern. Spathidium bromelicola nov. spec. is similar to S. muscicola (extrusomes bluntly fusiform and 4 µm long vs. rod-shaped and > 15 µm long) and S. stammeri (resting cyst wall smooth vs. spinous). Spathidium wolfi nov. spec. has an anterior and a posterior contractile vacuole. It differs from the supposed nearest relative, S. faurefremieti, by body size (on average 135 × 25 µm vs. 240 × 17 µm), the shape of the macronucleus (moniliform vs. a long, tortuous strand), and the total number of dorsal brush bristles (on average 47 vs. 72). The bent oral bulge of Arcuospathidium bromelicola and Spathidium bromeliophilum as well as the occurrence of lepidosomes on the cyst surface of Arcuospathidium bromelicola and Protospathidium lepidosomatum are discussed.

There is a widespread belief that spathidiids have few morphological features. In contrast, we show a rich morphological diversity in five new species discovered in tank bromeliads from the Caribbean, using live observation; protargol impregnation; morphometry; scanning electron microscopy; and resting cyst morphology, demonstrating lepidosomes (organic scales) for the first time in spathidiid haptoria. Arcuospathidium bromelicola nov. spec. is very similar to the previously described A. muscorum but its resting cyst has conspicuous, pillar-shaped lepidosomes on the surface. Protospathidium lepidosomatum nov. spec. is very similar to the previously described P. muscicola but has outstanding, nipple-shaped (vs. conical) lepidosomes on the cyst surface. Spathidium bromeliophilum nov. spec., whose ontogenesis is highly similar to that of S. turgitorum, differs from similar species by the body length:width ratio, the number of ciliary rows, the shape of the oral bulge, and details of the ciliary pattern. Spathidium bromelicola nov. spec. is similar to S. muscicola (extrusomes bluntly fusiform and 4 µm long vs. rod-shaped and > 15 µm long) and S. stammeri (resting cyst wall smooth vs. spinous). Spathidium wolfi nov. spec. has an anterior and a posterior contractile vacuole. It differs from the supposed nearest relative, S. faurefremieti, by body size (on average 135 × 25 µm vs. 240 × 17 µm), the shape of the macronucleus (moniliform vs. a long, tortuous strand), and the total number of dorsal brush bristles (on average 47 vs. 72). The bent oral bulge of Arcuospathidium bromelicola and Spathidium bromeliophilum as well as the occurrence of lepidosomes on the cyst surface of Arcuospathidium bromelicola and Protospathidium lepidosomatum are discussed.

Fuscheriid haptorids are characterized by meridionally extending ciliary rows clearly separated from the dikinetidal circumoral kinety; a two- or three-rowed dorsal brush; and oral basket rods (nematodesmata) originating from both, the circumoral dikinetids and from some oralized monokinetids in the anterior portion of the ciliary rows. Using standard morphological methods, we describe four new fuscheriid taxa, each discovered in a specific biogeographic region. Fuscheriides tibetensis nov. gen., nov. spec. has rod-shaped extrusomes and two dorsal brush rows. It is a small (~ 80 × 10 μm), slender ciliate with only seven ciliary rows, and was discovered in grassland soil of southern Tibet, about 4600 m above sea-level. Aciculoplites ethiopiensis nov. gen., nov. spec. has acicular extrusomes and two dorsal brush rows. It is a middle-sized (~ 100 × 30 μm), oblong ciliate with about 22 ciliary rows, and was discovered in floodplain soil from a lake in Ethiopia. Fuscheria uluruensis nov. spec., which we discovered in mud and aeolic soil from pools on top of the Ayers Rock in the red centre of Australia, is unique in having the macronucleus split into about 12 oblong nodules. The nodules originate post-divisionally via the branching macronucleus strand, as in multinucleate spathidiids. Fuscheria nodosa salisburgensis nov. sspec., which was discovered in mud and soil of a meadow pool in Salzburg (Austria), has a long, tortuous macronucleus and about 45 ciliary rows. The resting cyst has an escape apparatus absent from the cyst of F. uluruensis, indicating that Fuscheria is non-monophyletic.

Bromeliothrix metopoides was discovered in tank bromeliads from Central and South America. Pure cultures could be established in various media stimulating growth of its food, i.e. bacteria and heterotrophic flagellates of the genus Polytomella. The new ciliate was investigated in the light- and scanning electron microscope, with various silver impregnation techniques, and with molecular methods, using the small-subunit rDNA. The morphology and its changes during the life cycle are documented by 167 figures and a detailed morphometry. Bromeliothrix metopoides is about 27–55 × 22–36 μm in size and has a complex life cycle with Metopus-shaped, bacteriophagous theronts and trophonts (microstomes) and obovate, flagellate-feeding macrostomes having a large, triangular oral apparatus. The thin-walled

The morphology and ontogenesis of a new psilotrichid ciliate, Hemiholosticha pantanalensis, were studied using live observation, protargol impregnation, and scanning electron microscopy. Diagnostic features of the new species include: a medium-sized, almost circular to broadly obovate body with a short anterior projection; two macronuclear nodules with a single micronucleus in between; a total of about 35 cirri arranged in three ventral, one postoral, one right and one left marginal row; three dorsal kineties extending along prominent ribs; an adoral zone occupying about 60% of body length; and intracellular, eyespot-bearing, green algae almost filling the body. The ontogenesis of H. pantanalensis follows the psilotrichid mode, being a mixture of features found not only in various hypotrich taxa but also in other spirotrich groups. Specifically, the oral primordium develops in a deep pouch as in euplotids and oligotrichs, the anlage for the undulating membranes does not produce cirri as in euplotids and some schmidingerothrichids, and the longitudinal ventral cirral row R3 develops from two anlagen as in some amphisiellids and kahliellids. Since psilotrichids are classified in a polytomy of main hypotrich lineages in 18S rRNA gene phylogenies, some of their ontogenetic features might be ancient spirotrich plesiomorphies while others might be homoplasies.