This revision of the classification of eukaryotes follows that of Adl et al., 2012 [ J. Euk. Microbiol . 59(5)] and retains an emphasis on protists. Changes since have improved the resolution of many nodes in phylogenetic analyses. For some clades even families are being clearly resolved. As we had predicted, environmental sampling in the intervening years has massively increased the genetic information at hand. Consequently, we have discovered novel clades, exciting new genera and uncovered a massive species level diversity beyond the morphological species descriptions. Several clades known from environmental samples only have now found their home. Sampling soils, deeper marine waters and the deep sea will continue to fill us with surprises. The main changes in this revision are the confirmation that eukaryotes form at least two domains, the loss of monophyly in the Excavata, robust support for the Haptista and Cryptista. We provide suggested primer sets for DNA sequences from environmental samples that are effective for each clade. We have provided a guide to trophic functional guilds in an appendix, to facilitate the interpretation of environmental samples, and a standardized taxonomic guide for East Asian users.
The strawberry poison frog Dendrobates pumilio (Anura: Dendrobatidae) and related poison frogs contain a variety of dendrobatid alkaloids that are considered to be sequestered through the consumption of alkaloid-containing arthropods microsympatrically distributed in the habitat. In addition to ants, beetles, and millipedes, we found that adults of two species of oribatid mites belonging to the cohort Brachypylina, trophically a lower level of animal than ants and beetles, contain dendrobatid alkaloids. Gas chromatography/mass spectrometry (GC/MS) of hexane extracts of adult Scheloribates azumaensis (Oribatida: Acari) revealed the presence of not only pumiliotoxin 251D (8-hydroxy-8-methyl-6-(2'-methylhexylidene)-1-azabicyclo[4.3.0]nonane), but also precoccinelline 193C and another coccinelline-type alkaloid. From the corresponding extracts of an unidentified Scheloribates sp., pumiliotoxin 237A (8-hydroxy-8-methyl-6-(2'-methylpentylidene)-1-azabicyclo[4.3.0]nonane) was detected as a minor component, and identified by synthesis. The presence of related alkaloids, namely deoxypumiliotoxin 193H, a 6,8-diethyl-5-propenylindolizidine, and tentatively, a 1-ethyl-4-pentenynylquinolizidine, were indicated by the GC/MS fragmentation patterns, along with at least another six unidentified alkaloid components. Thus, one possible origin of pumiliotoxins, coccinellid alkaloids, and certain izidines found in poison frogs may be mites of the genus Scheloribates and perhaps related genera in the suborder Oribatida.
Population dynamics and feeding habits of the testate amoebae Nebela tincta and Hyalosphenia papilio were studied along a short "fen" to "bog" gradient in a Sphagnum-dominated mire (Jura, France). Samples were collected in living "top segments" (0-3 cm) and early declining "bottom segments" (3-6 cm) of Sphagnum fallax peat. Observations of digestive vacuole content and stable isotope analyses ((13)C and (15)N) were used to establish the feeding behavior of both testate amoeba species. Owing to their vertical distribution, the feeding habit of H. papilio was described from top segments, and that of N. tincta from bottom segments. Among identified food sources, those most frequently ingested by N. tincta were spores and mycelia of fungi (55%), microalgae (25%) and cyanobacteria (8.5%). For H. papilio, the most frequently ingested prey were ciliates (55%) and microalgae (35%). Nonmetric Multidimensional Scaling analysis clearly demonstrated that the two species did not have the same feeding habit along the "fen-bog" gradient, and furthermore that a significant spatial split exists in the feeding behavior of H. papilio. Additionally, isotope analyses suggested that H. papilio and N. tincta did not have the same trophic position in the microbial food web, probably resulting from their different feeding strategies.
Dileptid and tracheliid ciliates have been traditionally classified within the subclass Haptoria of the class Litostomatea. However, their phylogenetic position among haptorians has been controversial and indicated that they may play a key role in understanding litostomatean evolution. In order to reconstruct the evolutionary history of dileptids and tracheliids, and to unravel their affinity to other haptorians, we have used a cladistic approach based on morphological evidence and a phylogenetic approach based on 18S rRNA gene sequences, including eight new ones. The molecular trees demonstrate that dileptids and tracheliids represent a separate subclass, Rhynchostomatia, that is sister to the subclasses Haptoria and Trichostomatia. The Rhynchostomatia are characterized by a ventrally located oral opening at the base of a proboscis that carries a complex oral ciliature. We have recognized two orders within Rhynchostomatia. The new order Tracheliida is monotypic, while the order Dileptida comprises two families: the new, typically bimacronucleate family Dimacrocaryonidae and the multimacronucleate family Dileptidae. The Haptoria evolved from the last common ancestor of the Litostomatea by polarization of the body, the oral opening locating more or less apically and the oral ciliature simplifying. The Trichostomatia originated from a microaerophylic haptorian by further simplification of the oral ciliature, possibly due to an endosymbiotic lifestyle.
Levicoleps biwae n. gen., n. sp. was discovered in organic mud on the shore of Lake Biwa, Japan. Its morphology and small subunit rRNA gene sequence were studied with standard methods. Further, we established a terminology for the colepid armour and selected four features for genus recognition: the number of armour tiers, the structure of the tier plates, the presence/absence of armour spines, and the number of adoral organelles (three or five). The Japanese colepid, a barrel-shaped ciliate with an average size of 75 x 45 microm, has six armour tiers and hirtus-type tier plates, but lacks armour spines, both in the environment and in laboratory culture. Thus, it is considered to represent a new genus. This rank is supported by the considerable genetic distance (7%) from the common Coleps hirtus. Although L. biwae looks quite similar to C. hirtus in vivo, it is very likely most closely related to Coleps amphacanthus, a species with conspicuous armour spines, as indicated by body size, the number of ciliary rows and, especially, the multiple caudal cilia. Lake Biwa is about four million years old and inhabited by many endemic organisms, ranging from algae to large fish. Thus, we suspect that L. biwae is restricted to Lake Biwa or, at least, to Asia. Based on literature data and the generic features established, we also propose the new genus Reticoleps for Coleps remanei Kahl, 1933, and resurrect the genus Pinacocoleps Diesing, 1865 to include Coleps incurvus Ehrenberg, 1833, Coleps pulcher Spiegel, 1926, Coleps tessalatus Kahl, 1930 and, probably, Baikalocoleps quadratus Obolkina, 1995a. Nine colepid genera are diagnosed and dichotomously keyed.
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