Sabine Agatha

Global diversity of aloricate Oligotrichea (Protista, Ciliophora, Spirotricha) in marine and brackish sea water.

Oligotrichids and choreotrichids are ciliate taxa contributing to the multi-step microbial food web and episodically dominating the marine microzooplankton. The global diversity and distribution of aloricate Oligotrichea are unknown. Here, the geographic ranges of the 141 accepted species and their synonyms in marine and brackish sea water are analyzed, using hundreds of taxonomical and ecological studies; the quality of the records is simultaneously evaluated. The aloricate Oligotrichea match the moderate endemicity model, i.e., the majority (94) of morphospecies has a wide, occasionally cosmopolitan distribution, while 47 morphospecies show biogeographic patterns: they are restricted to single geographic regions and probably include 12 endemic morphospecies. These endemics are found in the Antarctic, North Pacific, and Black Sea, whereas the “flagship” species Strombidinopsis cercionis is confined to the Caribbean Sea. Concerning genera, again several geographic patterns are recognizable. The species richness is distinctly lower in the southern hemisphere than in the northern, ranging from nine morphospecies in the South Pacific to 95 in the North Atlantic; however, this pattern is probably caused by undersampling. Since the loss of species might affect higher trophical levels substantially, the aloricate Oligotrichea should not any longer be ignored in conservation issues. The ecophysiological diversity is considerably larger than the morphological, and even tops the richness of SSrRNA and ITS haplotypes, indicating that probably more than 83–89% of the diversity in aloricate Oligotrichea are unknown. The huge challenge to discover all these species can only be managed by combining the expertises of morphological taxonomists, molecular biologists, ecologists, and physiologists.

The Biology and Ecology of Tintinnid Ciliates: Models for Marine Plankton

Planktonic protists both produce and consume most of the primary production in the world ocean. They not only play key roles in the oceans but also represent an astounding amount of diversity: ecological morphological and genetic. However, for most taxa their ecology, morphology, phylogeny and biogeography are either poorly known or appear to be largely unrelated to one another; this hinders our understanding of their biology as well as interpretation of emerging genetic data. Tintinnid ciliates represent a singular exception. Compared to nearly all other groups of planktonic protists, there is a very substantial and relatively detailed literature (both modern and historical) on tintinnids. This volume synthesizes knowledge concerning a wide variety of topics ranging from anatomy and systematics, physiology, behavior, ecology (including ecological roles, predators, parasites, biogeography, and cysts) to fossil history. It will appeal to an audience ranging from advanced undergraduates to researchers in the fields of Oceanography, Marine Biology and Microbial Ecology.

Reconciling Cladistic and Genetic Analyses in Choreotrichid Ciliates (Ciliophora, Spirotricha, Oligotrichea)

Fifty‐six features of halteriid, oligotrichid, and choreotrichid ciliates are cladistically analysed, including an updated hypothesis about the evolution of the somatic ciliary patterns. Based on its morphology, Lynnella clusters with Parastrombidinopsis, Parastrombidium, and Strombidinopsis, while it is basal to the other choreotrichids in the molecular phylogenies. The two clusters of Favella species in small subunit rRNA gene trees are supported by morphological features, justifying a separation at genus and family level. The genus Favella has a smooth lorica surface and a somatic ciliary pattern comprising a left and lateral ciliary field as well as two dorsal kineties and a monokinetidal ventral kinety abutting on the right ciliary field. The new genus Schmidingerella n. gen., established for the second Favella cluster, groups with Metacylis and Rhabdonella in the molecular trees. It differs from Favella in (i) a lorica wall with reticulate surface ridges and minute openings and (ii) a ventral kinety that is distinctly apart from the right ciliary field and composed of a monokinetidal anterior and a dikinetidal posterior portion. The genera Codonaria, Codonella, and Codonellopsis are affiliated with the family Dictyocystidae, whose diagnosis is improved to include the lorica sac.

Updated hypothesis on the evolution of oligotrichid ciliates (Ciliophora, Spirotricha, Oligotrichida) based on somatic ciliary patterns and ontogenetic data

The two recently established genera ApostrombidiumXu et al., 2009 and VaristrombidiumXu et al., 2009 and the analysis of ontogenetic data in Strombidium constrictum, S. montagnesi, S. wilberti, Omegastrombidium elegans, and Paratontonia gracillima necessitated a revision of the hypothesis about the somatic ciliary pattern evolution in oligotrichid ciliates. As a consequence, the species-rich genus Strombidium was split, establishing two genera for species with a horizontal girdle kinety posterior to the oral primordium: Opisthostrombidium nov. gen. with the extrusome attachment sites along the anterior margin of the girdle kinety and posterior to the oral primordium and Foissneridium nov. gen. with the extrusome attachment sites distinctly apart from the girdle kinety and anterior to the oral primordium. The ontogenetic data revealed that the Ω-shaped girdle kinety pattern evolved convergently from the Pseudotontonia pattern with its horizontal girdle kinety in the tailed genus Paratontonia and from the Novistrombidium pattern with its dextrally spiralled girdle kinety in the tailless genus Omegastrombidium. The somatic ciliary pattern of the latter genus probably gave rise to the patterns of Apostrombidium and Varistrombidium.

Morphology and Morphogenesis of Metopus hasei Sondheim, 1929 and M. inversus (Jankowski, 1964) nov. comb. (Ciliophora, Metopida)

ABSTRACT The morphology and morphogenesis of Metopus hasei Sondheim, 1929 and M. inversus (Jankowski, 1964) n. comb, were investigated using live observation, silver impregnation, and scanning electron microscopy. Metopus has a spiral body organization and the ventral margin of the preoral dome bears five specialized ciliary rows, that form the so‐called perizonal stripe. Division is homothetogenic, occurs in freely motile (i. e. non‐encysted) condition, and includes a partial reorganization of the parental oral apparatus. During division, the complicated cell shape becomes ellipsoidal and all ciliary rows arrange meridionally. Stomatogenesis is entirely somatic (≅ pleurotelokinetal) and commences with the formation of kinetofragments in some dorsolateral kineties. The fragments become the opisthes adoral membranelles, while the paroral membrane is generated by the left two perizonal ciliary rows, which proliferate kinetids intrakinetally. The perizonal stripe of the opisthe is generated by the three right parental perizonal kineties, which divide, and by two dorsolateral ciliary rows, which are added. The morphogenetic processes, especially the unique mode of formation of the paroral membrane, are used to define the order Metopida Jankowski, 1980 n. stat. more properly. The ontogenetic, ultrastructural, and sequence data available give no clear indication about metopid phylogeny, but definitely exclude metopids from the classical heterotrichs, with which they were classified for more than 100 years. Accordingly, we place the Metopida as incertae sedis in the subphylum Intramac‐ronucleata Lynn, 1996.

Morphology, infraciliature, and ecology of some strobilidiine ciliates (ciliophora, oligotrichea) from coastal brackish water basins of Germany

Summary The morphology and ecology of some strobilidiine ciliates from brackish water basins adjacent to the North Sea of Germany (Dithmarscher and Beltringharder Koog) were investigated using Lugol fixed material, life observation and protargol impregnation. Two species are redescribed: Rimostrombidium caudatum (Kahl, 1932) nov. comb. and R. conicum (Kahl, 1932). For these species neotype specimens are designated. Rimostrombidium veniliae (Montagnes & Taylor, 1994) was recorded from this area for the first time and is briefly described. The ecological data comprise the abundance at different grades of salinity and temperature, seasonal occurrence and content of food vacuoles.

Intraclass evolution and classification of the Colpodea (Ciliophora).

ABSTRACT. Using nine new taxa and statistical inferences based on morphological and molecular data, we analyze the evolution within the class Colpodea. The molecular and cladistic analyses show four well‐supported clades: platyophryids, bursariomorphids, cyrtolophosidids, and colpodids. There is a widespread occurrence of homoplasies, affecting even conspicuous morphological characteristics, e.g. the inclusion of the micronucleus in the perinuclear space of the macronucleus. The most distinct changes in the morphological classification are the lack of a basal divergence into two subclasses and the split of the cyrtolophosidids into two main clades, differing mainly by the presence vs. absence of an oral cavity. The most complex clade is that of the colpodids. We partially reconcile the morphological and molecular data using evolutionary systematics, providing a scenario in which the colpodids evolved from a Bardeliella‐like ancestor and the genus Colpoda performed an intense adaptive radiation, giving rise to three main clades: Colpodina n. subord., Grossglockneriina, and Bryophryina. Three new taxa are established: Colpodina n. subord., Tillinidae n. fam., and Ottowphryidae n. fam. Colpodean evolution and classification are far from being understood because sequences are lacking for most species and half of their diversity is possibly undescribed.

Beyond the “Code”: A Guide to the Description and Documentation of Biodiversity in Ciliated Protists (Alveolata, Ciliophora)

Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates (IRCN‐BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN‐BC proposes to populate The Ciliate Guide, an online database, with biodiversity‐related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data.

Morphologic and genetic variability in the marine planktonic ciliate Laboea strobila Lohmann, 1908 (Ciliophora, Oligotrichia), with notes on its ontogenesis.

Abstract Laboea strobila Lohmann, 1908 is a conspicuous oligotrich ciliate in the marine plankton. In order to compare different populations, the morphology of specimens from the Mediterranean Sea, North Sea, and Irish Sea was investigated using live observation, protargol impregnation, and scanning electron microscopy. Furthermore, the PCR-amplified products of the SSrRNA gene from a monoclonal culture of L. strobila from the Mediterranean Sea were sequenced and aligned with sequences of other oligotrichs, including a population of L. strobila from the Atlantic coast of the USA. Finally, the data from the ecological literature were summarized and the cultivation methods were described. The SSrRNA gene sequences of the two distantly located L. strobila populations from the North Atlantic are identical. Likewise, the morphometrics of most populations so far investigated after protargol impregnation (i.e. from the North Atlantic) do not show obvious differences. In all computed phylogenetic trees, L. strobila groups with Strombidium species, forming a monophyletic taxon corresponding to the subclass Oligotrichia. These results are corroborated by the ontogenetic comparison. Since no type species was fixed for Laboea Lohmann, 1908, L. strobila was designated in the present paper.

Updating Biodiversity Studies in Loricate Protists: The Case of the Tintinnids (Alveolata, Ciliophora, Spirotrichea)

Species determination is crucial in biodiversity research. In tintinnids, identification is based almost exclusively on the lorica, despite its frequent intraspecific variability and interspecific similarity. We suggest updated procedures for identification and, depending on the aim of the study, further steps to obtain morphological, molecular, and ecological data. Our goal is to help improving the collection of information (e.g. species re‐/descriptions and DNA barcodes) that is essential for generating a natural tintinnid classification and a reliable reference for environmental surveys. These suggestions are broadly useful for protistologists because they exemplify data integration, quality/effort compromise, and the need for scientific collaborations.