Intraclass Evolution and Classification of the Colpodea (Ciliophora) (original) (raw)
Related papers
Journal of Eukaryotic Microbiology, 2011
We studied the morphology, morphometry, resting, and reproductive cysts, as well as the molecular phylogeny of Bryophrya gemmea n. sp., a colpodid ciliate that was discovered in ephemeral puddles in Idaho, northwest United States. This new species is distinguished from congeners by the irregularly pentagonal adoral organelles, four to five vestibular kineties, the single micronucleus, and one to three rows of brightly refractive protuberant interkinetal cortical granules to the right of the preoral suture. Resting cysts have two distinct membranes and an outer mucous coat. As typical for most colpodids, reproduction occurs in division cysts but details of ontogenesis are unknown. The 18S rRNA gene sequence shows only weak support for the phylogenetic relationship between Bryophrya and the bryophryid genus Notoxoma previously inferred from morphologic characters. Further, our molecular phylogenies classify bryophryids rather basal within the order Colpodida, not supporting ordinal status suggested by morphologists. Based on molecular data and morphologic characters, the colpodid genus Ilsiella is removed from the family Marynidae and placed in a new family, Ilsiellidae. Considering the molecular data, an evolutionary scenario for the formation of colpodid oral structures from a cyrtolophosidid ancestor through a bryophryid intermediate is proposed.
Journal of Molecular Evolution, 1999
Molecular analyses have been used recently to refine our knowledge of phylogenetic relationships within the ciliated protozoa (phylum Ciliophora). A current Hennigian phylogeny of the orders in the class Colpodea, based on light and electron microscopic analyses, makes three important assumptions with regard to apomorphic character states, namely, (1) that the kreyellid silver line evolved early in colpodean phylogeny, separating bryometopids, such as Bryometopus, from all other colpodeans; (2) that the macro–micronuclear complex is an autapomorphy of the cyrtolophosidids, such as Platyophrya; and (3) that merotelokinetal stomatogenesis is an apomorphic character of colpodids, such as Colpoda, Bresslaua, and Pseudoplatyophrya. These predictions of relationships within the class Colpodea were investigated by determining the complete small subunit rRNA gene sequences for the colpodid Bresslaua vorax, the grossglockneriid Pseudoplatyophrya nana, and the cyrtolophosidid Platyophrya vorax and a partial sequence for the bryometopid Bryometopus sphagni. These sequences were combined with the previously published complete SSrRNA sequences for the colpodid Colpoda inflata and the bursariomorphid Bursaria truncatella. The affiliations were assessed using both distance matrix and maximum-parsimony analyses. The tree topologies for the class Colpodea were identical in all analyses, with bootstrap support for bifurcations always exceeding 60%. The results suggest the following. (1) Since the clade including Bryometopus and its sister taxon, Bursaria, is never basal, the kreyellid silver-line system evolved later in colpodean phylogeny and does not separate bryometopids from all other colpodeans. (2) Since Platyophrya is always the sister taxon to the other five genera, there is a fundamental phylogenetic significance for its macro–micronuclear complex. (3) Since the colpodids, Colpoda, Bresslaua, and Pseudoplatyophrya, always group in one clade, merotelokinetal stomatogenesis appears to be a derived character state.
European Journal of Protistology, 2014
Using 11 new SSU-rDNA sequences, we analyze relationships within the class Colpodea, especially of some uncommon taxa, such as Kalometopia duplicata, Cyrtolophosis minor, and Jaroschia sumptuosa. The sequences do not change the basic structure of the molecular Colpodea tree, i.e., all belong to one of the four molecular clades recognized by Foissner et al. (2011): Colpodida, Cyrtolophosidida, Bursariomorphida, and Platyophryida. The addition of three Colpoda sequences strengthens the observation that species of this genus are distributed over the whole molecular Colpodea tree. Very likely, this is caused by a fast radiation of Colpoda, several species of which then evolved independently, forming new genera and families. Cyrtolophosis minor, which belongs to the molecular Pseudocyrtolophosis clade, is referred to a new genus, Apocyrtolophosis nov. gen., characterized by a comparably large, deltoid oral opening, an unciliated posterior region, and the absence of an oblique kinety in the left oral polykinetid. Bryometopus triquetrus does not erase the paraphyly of its genus. Platyophrya vorax, P. spumacola, and P. bromelicola form a highly supported clade in the order Platyophryida. Platyophryides and Ottowphrya are close genetically but differ in the silverline pattern (colpodid vs. platyophryid).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2009
The ciliate family Cyrtolophosididae Stokes, 1888 contains species that are poorly known from both the morphological and molecular perspectives. To further our understanding of this family, one species, Aristerostoma marinum Kahl, 1931, was redescribed. Cells in our population had a mean in vivo size of 15¾8 mm. There were six rows of somatic kineties, as well as six dorsal kinetids belonging to sparsely ciliated somatic kineties. The oral apparatus comprised a bipartite paroral membrane and four adoral organelles. The optimal ecological tolerances for pH and O 2 matched those of the environment in which the specimens were collected, but were different for salinity and temperature. To further test the phylogenetic placement of the family Cyrtolophosididae with increased taxon sampling, the small subunit rDNA of three morphospecies was characterized: A. marinum, Aristerostoma sp. ATCC 50986 and Pseudocyrtolophopsis alpestris. Unconstrained and constrained molecular analyses supported the non-monophyly of the order Cyrtolophosidida. The family Cyrtolophosididae fell out separately from the rest of its order. Haplotypes from previous environmental studies were also placed in a phylogenetic context within the class Colpodea.
Organisms Diversity & Evolution, 2013
Within the Pycnogonida, genetic studies have revealed that Colossendeis megalonyx Hoek (Challenger Report, Zoology, 3(X), 1-167, 1881), consists of a complex of several cryptic or overlooked species. Colossendeis megalonyx is a typical Southern Hemisphere species complex distributed primarily on the continental shelves in the Antarctic and Subantarctic. However, a different Colossendeis species with a completely different geographic distribution range, Colossendeis tenera Hilton (Journal of Entomology and Zoology, Pomona College, Claremont, 35(1), 2-4, 1943), was considered a subspecies of Colossendeis megalonyx by Turpaeva (Trudy Instituta Okeanology "P. P. Shirshova", Akademy Nauk SSSR, 103, 230-246, 1975). Colossendeis tenera occurs predominantly along the Pacific Coast of North America from the Bering Sea to central California. Prominent differences between these two currently distinct species are found in body proportions and other characters that were interpreted by Turpaeva as a possible case of pedomorphosis induced by deep-sea conditions. In this study, we tested the hypothesis that Colossendeis tenera belongs to the Colossendeis megalonyx complex by analyzing available and novel sequence data (CO1 and H3) of both Colossendeis megalonyx and Colossendeis tenera as well as a similar, apparently closely related species, Colossendeis angusta Sars (Archiv for Mathematik og Naturvidenskab, 2, 237-271, 1877). We compared morphometric data and SEM of the ovigera of these species. Our results clearly indicate that Colossendeis tenera and Colossendeis angusta are not a part of the Colossendeis megalonyx complex. A sister-group relationship of Colossendeis tenera and Colossendeis angusta is strongly supported, but Colossendeis tenera is not clearly resolved as monophyletic with respect to Colossendeis angusta. This work highlights the need for further examination of the variation found in the tenera-angusta clade. It also gives a first hint of the phylogenetic affinities of species within Colossendeis.
2012
. Morphology and phylogeny of a new woodruffiid ciliate, Etoschophrya inornata sp. n. (Ciliophora, Colpodea, Platyophryida), with an account on evolution of platyophryids. -Zoologica Scripta, 00, 000-000. We studied the morphology, morphometry, resting cysts and molecular phylogeny of a new woodruffiid ciliate, Etoschophrya inornata, from ephemeral puddles and two lacustrine habitats in Idaho, North-west USA. Up to now, the genus Etoschophrya has included a single species, Etoschophrya oscillatoriophaga, from which our new form is distinguished by (i) the absence of interkinetal cortical granules and, consequently, the absence of extrusible red material in methyl green-pyronin stains, (ii) usually ‡5 adoral membranelles vs. usually four, (iii) greater length and length ⁄ width ratio, (iv) prominent cortical furrows vs. inconspicuous and (v) adaptation to non-saline semi-terrestrial and lacustrine habitats in the Nearctic vs. highly saline alkaline Afrotropic soil habitats. Resting cysts have two distinct membranes and a thick hyaline mucous pericyst layer. However, only one membrane persists in older cysts. Like its congener, Etoschophrya inornata feeds exclusively on filamentous cyanobacteria. The 18S rRNA gene sequence places this species in a strongly supported clade with Kuklikophrya ougandae basal to the other platyophryids. We include a morphologic cladistic analysis of platyophryid ciliates and present a hypothetical scenario for the evolution of the platyophryid oral structures.
The Journal of Protozoology, 1991
The complete small subunit rRNA gene sequences of the heterotrich Blepharisma americanum and the colpodid Colpoda inflata were determined to be 17 19 and 1786 nucleotides respectively. The phylogeny produced by comparisons with other ciliates indicated that C. inflata is allied more closely with the nassophoreans and oligohymenophoreans than the spirotrichs. This is consistent with the placement of the colpodids in the Class Copodea. Blepharisma americanum was not grouped with the hypotrichs but instead was placed as the earliest branching ciliate. The distinct separation of B. americanum supports the elevation to class status given the heterotrichs based on morphological characters.
Molecular Phylogeny of the Cyrtophorid Ciliates (Protozoa, Ciliophora, Phyllopharyngea)
2012
Evolutionary relationships of cyrtophorian ciliates are poorly known because molecular data of most groups within this subclass are lacking. In the present work, the SS rRNA genes belonging to 17 genera, 7 families of Cyrtophoria were sequenced and phylogenetic trees were constructed to assess their inter-generic relationships. The results indicated: (1) the assignment of cyrtophorians into two orders is consistently confirmed in all topologies; (2) the order Dysteriida is an outlined monophyletic assemblage while Chlamydodontida is paraphyletic with three separate monophyletic families; (3) Microxysma, which is currently assigned within the family Hartmannulidae, should be transferred to the family Dysteriidae; (4) the systematic position of Plesiotrichopidae remains unclear, yet the two genera that were placed in this family before, Pithites and Trochochilodon, should be transferred to Chlamydodontida; (5) a new family, Pithitidae n. fam., based on the type genus Pithites was suggested; and (6) the sequence of Isochona sp., the only available data of Chonotrichia so far, is probably from a misidentified species. In addition, three group I introns of SS rRNA gene were discovered in Aegyriana oliva, among which Aol.S516 is the first IE group intron reported in ciliates.
An attempt at reconstructing a phylogenetic tree of the Ciliophora using parsimony methods
European Journal of Protistology, 1994
Phylogenetic trees were constructed for the Ciliophora using a parsimony analysis that applies the Camin-Sokal method to characters of known polarity and the Wagner method (which requires no knowledge of the ancestral state) to the other characters. The data covered 56 species and 23 morphological, nuclear and ultrastructural multistate characters. Since no real-world outgroup can be assumed with certainty to root the ciliophoran tree, we used three hypothetical ancestor hypotheses; only one of them (hypothesis 3: somatic kinetosomes in pairs considered ancestral; no character transformation series assumed for the position of the buccal area or for the organization of the buccal infraciliature) produced interesting trees. Two trees, called A and D, have been retained because they were shorter than the others and were equally optimal for different codings of the hypothetical ancestor. In tree A, there is an early separation in two main branches. The first one contains two groups: the Karyorelictea-Heterotrichea (Postciliodesmatophora) and the Hypotrichea-Oligotrichea (Spirotricha) on the one hand, and the colpodids (Transversala) on the other. The second branch leads to 3 groups containing all other ciliates. In tree D, the Postciliodesmatophora and Spirotricha are first separated from all other ciliates; this is in agreement with molecular phylogenies. Despite these differences, the same five major groups appear in both trees; the main difference is in the position of the colpodid group. Class Karyorelictea appears to be polyphyletic, with (a) a Loxodia-Trachelocercia line whose genera share the same type of somatic cortex and nuclear organization, and (b) a Protoheterotrichia-Protocruziidia line which is closer to the Heterotrichiao Nyctotherus is closer to the hypotrichs than to the heterotrichs. As in the molecular trees, the heterotrichs are closer to some of the Karyorelictea, with which they share the same main type of cortical cytoskeleton (postciliary ribbons), than to the hypotrichs and oligotrichs, where the cortical microtubules are not postciliary fibers. So, there are two competing types of reinforcement of the cell cortex by microtubules, and these were selected as early as the first (in tree D) or the second branching (in tree A); this is justification enough to consider the subphylum Tubulicorticata as totally artificial. The validity of the subphylum Filocorticata is also discussed, considering the cortical cytoskeleton of some of the Vestibuliferea (Blepharocorythida and Entodiniomorphida), The Litostomatea, Vestibuliferea and Phyllopharyngea emerge as a sister-group of the Oligohymenophorea. In the phyllopharyngids, macronuclear DNA is gene-sized, as in the hypotrichs; this means that DNA fragmentation occurs independently in different lineages. Macronuclear characters concerning chromatin organization that depend on the size of the DNA molecules have become diversified into paraphyletic lines such as the phyllopharyngids, oligotrichs and hypotrichs for the character "DNA duplication in replication bands". Nassula is separated from the Furgasonia-Pseudomicrothorax group, which is close to the scuticociliates. Nassula is close to Coleps. The peniculids branch away markedly from the tetrahymenids and are closer to the scuticociliates and peritrichs. The results are discussed with reference to some other new data, phylogenetic reconstructions and molecular trees.
Arthropod fossil data increase congruence of morphological and molecular phylogenies
The interrelationships of major arthropod clades have long been contentious, but refinements in molecular phylogenetics underpin an emerging consensus. Striking topologies from these studies include the position of hexapods (insects) within a paraphyletic Crustacea, and a putative myriapod/chelicerate alliance. Although some morphological characters support these groupings, they have not been recovered in large-scale phylogenetic analyses based on morphology. An analysis herein of 753 morphological characters for 309 fossil and Recent panarthropods shows enhanced congruence with molecular phylogenies. We resolve hexapods within Crustacea, with remipedes their closest extant relatives. Selective taxon and character removal exposes the traditional myriapod/hexapod linkage as an artefact of convergent character acquisition during terrestrialisation. Fossils break up such long branches, their intermediate morphologies linking clades that have otherwise had their ancestral conditions overprinted. Pycnogonids are an exemplar, grouping with euchelicerates when fossils are included, and as sister-taxon to all other extant arthropods when fossils are removed.