Exploring species diversity of lissorchiid trematodes (Digenea: Lissorchiidae) associated with the gravel snail, Lithoglyphus naticoides, in European freshwaters

2020 ◽  
Vol 94 ◽  
Author(s):  
R. Petkevičiūtė ◽  
G. Stanevičiūtė ◽  
V. Stunžėnas

Abstract Comparative analysis using complete ITS2 and partial 28S rDNA sequence data revealed that cercariaeum developing in rediae in Lithoglyphus naticoides represent two different lissorchiid species. One morphotype of cercariaeum is conspecific with adult Palaeorchis incognitus from European roach, Rutilus rutilus. The other cercariaeum is attributable to the genus Asymphylodora, but the species identity is not yet determined. We also generate the first rDNA sequences for Asymphylodora progenetica based on new collections from Bithynia tentaculata from Lithuania. Phylogenetic analyses of the newly generated sequences, together with information for other lissorchiids available on GenBank, showed that all representatives of Lissorchiidae form a strongly supported clade. Three monophyletic lineages, Asymphylodora, Palaeorchis and Lissorchis, were recognized at the generic level. Karyological analysis of the chromosome set of larval P. incognitus revealed a diploid number of 2n = 20. Its karyotype with subtelocentric chromosomes prevailing can be regarded as comparatively ‘primitive’, which is consistent with the basal position of P. incognitus in the 28S tree relative to the representatives of the genus Asymphylodora. The present study adds significant new information for establishing species-specific markers for the confident characterization of different developmental stages of lissorchiid species and clarification of their life cycles.

2001 ◽  
Vol 33 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Gert Helms ◽  
Thomas Friedl ◽  
Gerhard Rambold ◽  
Helmut Mayrhofer

AbstractThe identity of photobionts from 20 species of the Physciaceae from different habitats and geographical regions has been determined by ITS rDNA sequence comparisons in order to estimate the diversity of photobionts within that lichen group, to detect patterns of specificity of mycobionts towards their photobionts and as a part of an ongoing study to investigate possible parallel cladogenesis of both symbionts. Algal-specific PCR primers have been used to determine the ITS rDNA sequences from DNA extractions of dried lichens that were up to 5 years old. Direct comparisons and phylogenetic analyses allowed the assignment of Physciaceae photobionts to four distinct clades in the photobiont ITS rDNA phylogeny. The results indicate a diversity within the genus Trebouxia Puymaly and Physciaceae photobionts that is higher than expected on the basis morphology alone. Physciaceae photobionts belonged to 12 different ITS lineages of which nine could unambiguously be assigned to six morphospecies of Trebouxia. The identity of the remaining three sequences was not clarified; they may represent new species. Specificity at the generic level was low as a whole range of photobiont species were found within a genus of Physciaceae and different ranges were detected. The photobionts of Physcia (Schreb.) Michaux were closely related and represented one morphospecies of Trebouxia, whereas the algal partners of Buellia De Not and Rinodina (Ach.) Gray were in distant lineages of the ITS phylogeny and from several Trebouxia morphospecies. Photobiont variation within a genus of Physciaceae may be due to phylogeny, geographical distance or because photobionts from neighbouring lichens were taken (“algal sharing“). At the species level Physciaceae mycobionts seem to be rather selective and contained photobionts that were very closely related within one morphospecies of Trebouxia.


2011 ◽  
Vol 86 (2) ◽  
pp. 245-251 ◽  
Author(s):  
R.S. Dai ◽  
G.H. Liu ◽  
H.Q. Song ◽  
R.Q. Lin ◽  
Z.G. Yuan ◽  
...  

AbstractSequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochromecoxidase subunit 1 (cox1) and NADH dehydrogenase subunit 4 (nad4), and internal transcribed spacer (ITS) of rDNA among and within three cestodes,Spirometra erinaceieuropaei,Taenia multicepsandTaenia hydatigena, from different geographical origins in China was examined. A portion of thecox1 (pcox1),nad4 genes (pnad4) and the ITS (ITS1+5.8S rDNA+ITS2) were amplified separately from individual cestodes by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. While the intra-specific sequence variations within each of the tapeworm species were 0–0.7% for pcox1, 0–1.7% for pnad4 and 0.1–3.6% for ITS, the inter-specific sequence differences were significantly higher, being 12.1–17.6%, 18.7–26.2% and 31–75.5% for pcox1, pnad4 and ITS, respectively. Phylogenetic analyses based on the pcox1 sequence data revealed thatT. multicepsandT. hydatigenawere more closely related to the other members of theTaeniagenus, andS. erinaceieuropaeiwas more closely related to the other members of theSpirometragenus. These findings demonstrated clearly the usefulness of mtDNA and rDNA sequences for population genetic studies of these cestodes of socio-economic importance.


MycoKeys ◽  
2018 ◽  
Vol 41 ◽  
pp. 51-63 ◽  
Author(s):  
M. Ebinghaus ◽  
D. Begerow

Two new rust species, Raveneliapiepenbringiae and R.hernandezii (Pucciniales) on Senegalia spp. (Fabaceae) are described from the Neotropics (Panama, Costa Rica). A key to the species on neotropical Senegalia spp. is provided. Molecular phylogenetic analyses based on 28S rDNA sequence data suggest that the representatives of Senegalia rusts distributed in the neotropics evolved independently from species known from South Africa. This is further supported by the teliospore morphology, which is characterised by uniseriate cysts in the neotropical Senegalia rusts and contrasting multiseriate cysts in the paleotropic Ravenelia species that infect this host genus.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5783 ◽  
Author(s):  
María Capa ◽  
Torkild Bakken ◽  
Karin Meißner ◽  
Arne Nygren

BackgroundLong-bodied sphaerodorids (Annelida, Sphaerodoridae) is the common name for members of the three closely and morphologically homogenous currently accepted genera of benthic marine bristle worms:Ephesiella,EphesiopsisandSphaerodorum. Members of this group share the presence of two dorsal and longitudinal rows of macrotubercles with terminal papillae, and two longitudinal rows of microtubercles, features that are unique among sphaerodorids. Genera are distinguished by the chaetae morphology. Members ofEphesiellaare characterised by having compound chaetae (except, sometimes, simple chaetae in the first chaetigers),Sphaerodorumbear only simple chaetae, andEphesiopsishave both compound and simple chaetae in all parapodia.MethodsMitochondrial (partial COI and 16S rDNA) and nuclear (partial 18S rDNA and 28S rDNA) sequence data of long-bodied sphaerodorids with compound and simple chaetae, and an outgroup of additional seven sphaerodorid species were analysed separately and in combination using Bayesian inference (BA), and Maximum Likelihood (ML) methods. Long-bodied sphaerodorids from around the world (including type specimens) were examined under a range of optical equipment in order to evaluate putative generic and specific diagnostic features, in addition to intraspecific variability.ResultsPhylogenetic analyses of mitochondrial and nuclear DNA sequences of specimens identified asEphesiellaandSphaerodorum,based on chaeta morphology, were performed.SphaerodorumandEphesiellawere recovered as paraphyletic and nested within each other. Revision of current nominal species diagnostic features are performed and discussed.DiscussionResults contradict current generic definitions. Recovery of paraphyletic compound and simple chaetae clades urge the synonymization of these two genera of long-bodied sphaerodorids. Morphological data also suggest the synonymization ofEphesiopsis.


2011 ◽  
Vol 86 (3) ◽  
pp. 293-301 ◽  
Author(s):  
R. Petkevičiūtė ◽  
V. Stunžėnas ◽  
G. Stanevičiūtė

AbstractChromosome set and rDNA sequences of the larval digeneanCercariaeum crassumwere analysed in order to clarify its systematic position and possible adult form. Parasites were obtained from the sphaeriid bivalvePisidium amnicum, collected in Lithuanian and Finnish rivers. The karyotype is shown to consist of five pairs (2n = 10) of large, up to 14 μm, chromosomes. Complement, composed of a low diploid number of exclusively bi-armed elements, presumably arose through Robertsonian fusions of acrocentric chromosomes. Consistent with a Robertsonian-derived karyotype, one or two small, metacentric, mitotically stable B chromosomes were detected in the cells of parthenitae isolated from some host individuals. A phylogenetic analysis using rDNA internal transcribed spacer 2 (ITS2) and 28S sequences corroborates the allocation ofC. crassumto the family Allocreadiidae. In neighbour-joining and maximum parsimony phylogenetic treesC. crassumclusters into one clade withAllocreadiumspp., and is the closest sister group in relation toA. isoporum; the level of rDNA sequence divergence between them (2.67% for ITS2 and 1.16% for 28S) is consistent with the level expected for intrageneric variation. The present study adds significant information to a database for establishing species-specific characters for confident characterization of different developmental stages of allocreadiid species, clarification of their life cycles and evaluation of intra- and interspecific variability.


2021 ◽  
Vol 9 (8) ◽  
pp. 1586
Author(s):  
Tatyana Darienko ◽  
Cecilia Rad-Menéndez ◽  
Christine N. Campbell ◽  
Thomas Pröschold

Most marine coccoid and sarcinoid green algal species have traditionally been placed within genera dominated by species from freshwater or soil habitats. For example, the genera Chlorocystis and Halochlorococcum contain exclusively marine species; however, their familial and ordinal affinities are unclear. They are characterized by a vegetative cell with lobated or reticulated chloroplast, formation of quadriflagellated zoospores and living epi- or endophytically within benthic macroalgae. They were integrated into the family Chlorochytriaceae which embraces all coccoid green algae with epi- or endophytic life phases. Later, they were excluded from the family of Chlorococcales based on studies of their life histories in culture, and transferred to their newly described order, Chlorocystidales of the Ulvophyceae. Both genera form a “Codiolum”-stage that serves as the unicellular sporophyte in their life cycles. Phylogenetic analyses of SSU and ITS rDNA sequences confirmed that these coccoid taxa belong to the Chlorocystidales, together with the sarcinoid genus Desmochloris. The biflagellated coccoid strains were members of the genus Sykidion, which represented its own order, Sykidiales, among the Ulvophyceae. Considering these results and the usage of the ITS-2/CBC approach revealed three species of Desmochloris, six of Chlorocystis, and three of Sykidion. Three new species and several new combinations were proposed.


2021 ◽  
Author(s):  
Qiong Zhang ◽  
Lei Zhao ◽  
Jian-Li Zhao ◽  
Ryan A. Folk ◽  
Nelson Zamora ◽  
...  

Theaceae, with three tribes and nine genera, is a family of great economic and ecological importance. Recent phylogenetic analyses based on plastid genome resolved the relationship among three tribes and the intergeneric relationships within Gordonieae and Stewartieae. However, generic level relationships within the largest tribe Theeae were not fully resolved and potential hybridization among genera within Theeae revealed previously also remains to be tested further. Here we conducted a comprehensive phylogenomic study of Theaceae based on transcriptomes and low-depth whole-genome sequencing of 57 species as well as additional plastome sequence data from previous work. Phylogenetic analyses suggested that Stewartieae was the first-diverging clade in Theaceae, consistent with previous study using plastomic data. Within Theeae, the highly supported Apterosperma-Laplacea clade grouped with Pyrenaria with maximum support based on the partitioned and unpartitioned concatenation analyses using the 610 low-copy nuclear genes, leaving Camellia and Polyspora as another sister genera in the tribe. PhyloNet analyses suggested one reticulation event within Camellia and Pyrenaria respectively, but no intergeneric reticulations were detected in Theeae. Another introgression was found between Gordonia lasianthus and the common ancestor of Gordonieae during the Late Oligocene. The existing land bridges (e.g. Bering land bridge) might have facilitated this ancient introgression. Further researches need to be conducted to uncover the interspecific introgression pattern within Camellia. Ks distribution analyses supported the tea family shared one whole-genome duplication (WGD) event Ad-β, which was recently mapped to the clade containing core Ericales, Primuloids, Polemonioids and Lecythidaceae.


2021 ◽  
Vol 7 (7) ◽  
pp. 513
Author(s):  
Thuong T.T. Nguyen ◽  
Kerstin Voigt ◽  
André Luiz Cabral Monteiro de Azevedo Santiago ◽  
Paul M. Kirk ◽  
Hyang-Burm Lee

Three novel fungal species, Backusella chlamydospora sp. nov., B. koreana sp. nov., and B. thermophila sp. nov., as well as two new records, B. oblongielliptica and B. oblongispora, were found in Cheongyang, Korea, during an investigation of fungal species from invertebrates and toads. All species are described here using morphological characters and sequence data from internal transcribed spacer sequences of ribosomal DNA and large subunit of the ribosomal DNA. Backusella chlamydospora is different from other Backusella species by producing chlamydospores. Backusella koreana can be distinguished from other Backusella species by producing abundant yeast-like cells. Backusella thermophila is characterized by a variable (subglobose to oblong, applanate to oval, conical and ellipsoidal to pyriform) columellae and grows well at 37 °C. Multigene phylogenetic analyses of the combined ITS and LSU rDNA sequences data generated from maximum likelihood and MrBayes analyses indicate that B. chlamydospora, B. koreana, and B. thermophila form distinct lineages in the family Backusellaceae. Detailed descriptions, illustrations, phylogenetic tree, and taxonomic key to the Backusella species present in Korea are provided.


Parasitology ◽  
2015 ◽  
Vol 142 (6) ◽  
pp. 816-826 ◽  
Author(s):  
NELA DVOŘÁKOVÁ ◽  
JANA KVIČEROVÁ ◽  
MARTIN HOSTOVSKÝ ◽  
PAVEL ŠIROKÝ

SUMMARYThe uniform morphology of the developmental stages ofHaemogregarinaspecies and the insufficient information supplied by the simplistic descriptions of previous authors complicates their differential diagnosis and proper species identification. In this study, we detectedHaemogregarinaspp. in 6 out of 22 (27·2%) examined turtles originating from Southeast Asia,Malayemys subtrijuga(n= 4),Sacalia quadriocellata(n= 1) andPlatysternon megacephalum(n= 1), and compared them with the available literature data. Microscopic analysis of our isolates distinguished 2 morphological species,Haemogregarina pellegriniand one new species, being described in this paper asHaemogregarina sacaliaesp. n. Phylogenetic analyses based on 1210 bp long fragment of 18S rDNA sequences placed both haemogregarines firmly within the monophyleticHaemogregarinaclade. Isolates ofH. pellegrinifrom 2 distantly related turtle hosts,M. subtrijugaandP. megacephalum, were genetically identical. Despite the fact that numerousHaemogregarinaspecies of turtles have been described, the incompleteness of the morphological data and relatively low host specificity provides the space for large synonymy within this taxon. Therefore, a complex approach combining microscopic analyses together with molecular-genetic methods should represent the basic standard for all taxonomic studies.


2013 ◽  
Vol 87 (2) ◽  
pp. 211-216 ◽  
Author(s):  
Bernard L. Cohen ◽  
Maria Aleksandra Bitner

We present here the first report based on phylogenetic analyses of small subunit (SSU/18S) and large subunit (LSU/28S) ribosomal DNA (rDNA) sequences from a wider-than-token sample of rhynchonellide articulate brachiopods, with data from 11 of ∼20 extant genera (12 species) belonging to all four extant superfamilies. Data exploration by network and saturation analyses shows that the molecular sequence data are free from major aberrations and are suitable for phylogenetic reconstruction despite the presence of large deletions in four SSU rDNA sequences. Although molecular sequence analyses cannot directly illuminate the systematics of fossils, the independent, genealogical evidence and phylogenetic inferences about extant forms that they make possible are highly relevant to paleontological systematics because they highlight the limitations of evolutionary inference from morphology. Parsimony, distance, maximum likelihood (no clock) and Bayesian (relaxed-clock) analyses all find a tree topology that disagrees strongly with the existing superfamily classification. All tested phylogenetic reconstructions agree that the taxa analyzed fall into three clades designated A1, A2, and B that reflect two major divergence events. The relaxed-clock analysis indicates that clades A and B diverged in the Paleozoic, while clades A1 and A2 reflect Permo-Triassic (and later) events. Morphological homoplasy and possible gene co-option are suggested as the main sources for the discord between the morpho-classification, the results of cladistic analyses of morphology, and the relationships reconstructed from molecular sequences. The origin, function and evolutionary implications of the deletion-bearing rhynchonellide SSU rDNA sequences are briefly discussed in relation to pseudogenes and concerted evolution in the rDNA genomic region.


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