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Protistology ■ 81
DepartmentofTerrestrialEcology, Cologne, Germany [email protected]
The Centramoebida is a group of amoebozoans with flattened trophic cells that display finely pointed subpseudopodia and a prominent lamellate microtubular organizing center (MTOC). This group of amoebozoans has received considerable attention from the broader scientific community due to the pathenogenic nature and ecological importance of some of its members. Here we increase the known diversity of the Centramoebida by demonstrating through multi and single gene phylogenetics along with light and electron microscopy that the formally incertae sedis amoebozoans " Protostelium" pyriformis, "Protostelium" arachisporum, and Stereomyxa ramosa belong within the Centramoebida. We also describe Vacuolamoeba acanthaformis n.g. n.sp. a new centramoebid isolated from soil in Tibet. Our phylogenetic analyses recover a highly supported Centramoebida that includes highly supported clades comprised of "P." arachisporum, Stereomyxa ramosa and Vacuolamoeba acanthafor-mis respectively. We also show "P." pyriformis is robustly nested within the genus Acanthamoeba making it the first reported protosteloid member of the genus. As a result of these analyses, we formally transfer "Protostelium" arachisporum into the genus Luapelameoba and "Protostelium" pyriformis into the genus Acanthamoeba establishing the combinations Luapeleamoeba arachisporum n. comb. and Acanthamoeba pyriformis n. comb. Our results greatly increase the known diversity of this medically and ecologically important group, and further demonstrate the widespread nature of sporocarpic fruiting across the tree of Amoebozoa.
THE EVOLUTIONARY IMPORTANCE OF PREDATORY FLAGELLATES: NEW DEEP BRANCHES ON THE EUKARYOTIC TREE OF LIFE
Tikhonenkov D.V.1, Janouskovec J.2, Hehenberger E.3, Burki F.4, Gawryluk R.3, Karnkowska A.3, Mylnikov A.P.1, Keeling P.J.3
1 - Institute for Biology of Inland Waters, Russian Academy of Sciences
2 - Department ofGenetics, Evolution & Environment, University College London
3 - Botany Department, University ofBritish Columbia
4 - Systematic Biology Department, Uppsala University [email protected]
The origin and early radiation of major protist supergroups are linked to understanding key transitions in the evolution fo eukaryotes: endosymbiosis, genome evolution, and morphological novelty. This understanding is often limited by the absence of
reliable comparators; organisms with ancestral or intermediate features that represent sister groups of well-known taxa. Recent studies on the diversity of heterotrophic protists and environmental sequence data have indicated that many such "sister" lineages exist but remain insufficiently known primarily because they are not available in stable cultures. Among heterotrophs, predatory protists are of particular interest because their diversity may be the least understood of all protists: they are comparatively rare in natural samples and often difficult to maintain in the laboratory. However, their ability to feed on protozoa and microalgae is relevant to understanding the role ofphagotrophy in the origin of mitochondria and plastids, and many represent deep-branching evolutionary lineages that could help us illuminate the origin of major protist supergroups and resolve their relationships. Here we report the establishment of multiple cultures ofrare, free-living predatory flagellates, which occupy basal or intermediate evolutionary positions within major eukaryotic supergroups (Alveolata, Stramenopiles, Rhizaria, Opisthokonta, Kinetoplastida), or represent independent deep-branching eukaryotic lineages. Molecular and morphological data from these isolates reveals ancestral and unique morphological and ultrastructural features, slowly evolving nuclear genes, and large, slow-evolving mitochondrial gene sets.
This study was supported by the Russian Science Foundation (grant no. 14-14-00515).
DEVELOPMENT OF THE INTEGRATED INFORMATION WEB-SYSTEM ON A BIODIVERSITY OF PROTISTS "PROTIST.RU" Tikhonenkov D.V.1, Tychkov A.Yu.2, Azovsky A.I.3, Bobrov A.A.3, Plotnikov A.O.4, Tsyganov A.N.2, Mylnikov A.P.1
1 - Institute for Biology of Inland Waters, Russian Academy of Sciences
2 - Penza State University
3 - Moscow State University
4 - Institute for Cellular and Intracellular Symbiosis, Russian Academy of Sciences [email protected]
Protists are the most heterogeneous at cellular and molecular levels group of eukaryotes. They play an important role in ecosystem functioning as a part of microbial communities and have a high potential for human practical activity as a resource for the development of biotechnologies. Inventory, systematization, and integration of the data on the diversity of protists are of primary importance. We have made the technical platform and started the development of web-system, which allows
82 • "PROTIST—2016
integrating the information on morphological, molecular, and ecological features of different protist species. The content of the web-system will include morphological descriptions and differential diagnoses of the species, photos ofliving cells and whole mounts, electron-microscopic illustrations of coverings and cell ultrastructure, movies of live cells, drawings, sequences of phylogenetically important genes, molecular phylogenetic trees, databases on geographic and biotopic distribution of the species, protistological literature. Now we focus on four groups offree-living protists: heterotrophic flagellates, testate amoebae, ciliates, centroheliozoans. The work on interactive illustrative keys for some taxonomic groups was started. Registered on the website users can upload and edit content, create personal profiles, and topics on the forum. We invite all protistologists to join our team. The integrated web-system is available for observing on the Internet at http://protist.ru/. This study was supported by the Russian Foundation for Basic Research (grant 15-29-02518).
HIDDEN DIVERSITY OF FILOSE TESTATE AMOEBAE IN THE MIDDLE WATERSHED OF THE DANUBE Torok J.K.
Department of Systematic Zoology and Ecology, Eotvos Lorand University, Budapest [email protected]
Diversity of filose testate amoebae in the middle watershed of the Danube has been searched for decades, but still features with new detections. Corythionella golemanskyi is first time detected in Europe in satisfactory number of individuals for correct identification. Cyphoderia calceolus and Cyphoderia myosurus specimens found during the last twenty years make possible to distinguish between these two similar and rare taxa. Reviewing all the rare filose testaceans found in the middle watershed of River Danube from 1962 and considering their sampled microhabitats, we conclude that these species are generally adapted to low organic material content and high oxygen concentration. Testate amoeba species lists from Hungary are compared throughout five decades, highlighting habitat requirements for rare filoseans. We argue, that water flow has an important role in formation of riverine testate amoeba communities: Space clearing floods open new microhabitats for colonization from local refugia. Microhabitats like sandy riparian zone remaining free from intensive organic load are occasionally supplied with additional fresh ground water, and can maintain favourable environmental conditions for filoseans for a long time, while prevent
development of diverse lobosean assemblages. Striking similarity between assemblages of Penard in the profundal zone of deep Swiss lakes and the middle watershed of the Danube are attributed to the above environmental factors. It is still debated, why majority of the presented species have not been reported out of Europe. Finally, a concise methodological proposal is presented to the detection of these inconspicuous testate amoeba species. Funding: Hungarian Scientific Research Fund (T49632).
RARE CORYTHIONELLA AND CYPHODERIA SPECIES IN THE HUNGARIAN SECTION OF THE DANUBE Torok J.K.
Department of Systematic Zoology and Ecology, Eotvos Lorand University, Budapest [email protected]
Sandy sediment and seston were investigated in several sites north from Budapest along the Danube riparian zone in order to find rare filose testate amoebae. Finally, ca. 20 kilometers north from the capital Corythionella golemanskyi tests were detected in 2015, enough for morphometric analysis. A repeated sampling four months later resulted specimens of Cyphoderia calceolus with enormous form variations. Shell structure details and morphometry are given for both species. Characteristics of the latter are compared with those of Cyphoderia myosurus, detected in 1996—97 sampling of the Danube in the Szigetkoz area. As Penard (1908) has stated, Cyphoderia myosurus has elongated shell plates. Cyphoderia calceolus, however, comprises non-overlapping plates, often kidney shaped, without a regular circular outline. Morphometry of Corythionella golemanskyi shells leads us to conclude that the formerly found active Corythionella specimens (sampled in Szigetkoz Danube, 1996) belong to another species. The very first Corythionella specimens ever found in Hungary were detected as early as 1996 at the same site, but being not yet described, they were preserved as weird Cyphoderia laevis specimens. These data suggest that although Corythionella is present in the Danube, its shy appearence prevents it from recognition during analysis of turbid sediment samples. Funding: Hungarian Scientific Research Fund (T49632).
PARVULARIA GEN. NOV. REPRESENTS A FILOSE AMOEBA RELATED TO NUCLEA-RIIDS, THE EARLIEST-BRANCHING LINEAGE OF HOLOMYCOTA (OPISTHOKONTA) Torruella G.1, Lopez-Escardo D.2, Moreira D.1, Ruiz-Trillo I.2-3, Lopez-Garcia P.1
