scholarly journals Revision of the genus Cobbionema Filipjev, 1922 (Nematoda, Chromadorida, Selachinematidae)

2020 ◽  
Author(s):  
Mohammed Ahmed ◽  
Sven Boström ◽  
Oleksandr Holovachov
Keyword(s):  
Body Size ◽  
Maximum Likelihood ◽  
The Other ◽  
Rrna Genes ◽  
28S Rrna ◽  
The Family ◽  
Family Based ◽  
De Man ◽  
Distal Section ◽  
Bayesian Trees

This paper reports on the genus Cobbionema Filipjev, 1922 in Sweden with the description of four species and a revision of the genus. Cobbionema acrocerca Filipjev, 1922 is relatively small in size, with a tail that has a conical proximal and a digitate distal section. Cobbionema cylindrolaimoides Schuurmans Stekhoven, 1950 is similar to C. acrocerca in most characters except having a larger body size and heavily cuticularized mandibles. Cobbionema brevispicula sp. nov. is characterised by short spicules and a conoid tail. Cobbionema acuminata sp. nov. is characterised by a long two-part spicule, a conical tail and three (one mid dorsal and two ventrosublateral) sharply pointed tines in the anterior chamber of the stoma that are located more anterior than in all the other species. We also present a molecular phylogeny of the family based on the nearly full-length 18S and the D2-D3 expansion segment of the 28S rRNA genes. Maximum Likelihood and Bayesian trees inferred from both genes strongly support a clade that included Cobbionema, Demonema Cobb, 1894 and Halichoanolaimus de Man, 1888 and another clade with Gammanema Cobb, 1920 and Latronema Wieser, 1954 nested together. None of the trees supported the monophyly of the subfamilies Choniolaiminae and Selachinematinae.

Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses

2021 ◽  
Vol 95 ◽  
Author(s):  
B. Neov ◽  
G.P. Vasileva ◽  
G. Radoslavov ◽  
P. Hristov ◽  
D.T.J. Littlewood ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
18S Rrna ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Rrna Genes ◽  
Host Switching ◽  
28S Rrna ◽  
Mitochondrial Cytochrome ◽  
Rapid Radiation ◽  
18S Rrna Genes

Abstract The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1–D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631–641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

scholarly journals Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts (“Candidatus Bealeia paramacronuclearis” and “Candidatus Fokinia cryptica”) Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia

2016 ◽  
Vol 82 (24) ◽  
pp. 7236-7247 ◽  
Author(s):  
Franziska Szokoli ◽  
Michele Castelli ◽  
Elena Sabaneyeva ◽  
Martina Schrallhammer ◽  
Sascha Krenek ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Small Subunit ◽  
Sensu Stricto ◽  
The Other ◽  
Rrna Genes ◽  
Small Subunit Rrna ◽  
Taxonomic Assignment ◽  
Content Type ◽  
The Family ◽  
Critical Revision

ABSTRACTIn the past 10 years, the number of endosymbionts described within the bacterial orderRickettsialeshas constantly grown. Since 2006, 18 novelRickettsialesgenera inhabiting protists, such as ciliates and amoebae, have been described. In this work, we characterize two novel bacterial endosymbionts fromParameciumcollected near Bloomington, IN. Both endosymbiotic species inhabit the cytoplasm of the same host. The Gram-negative bacterium “CandidatusBealeia paramacronuclearis” occurs in clumps and is frequently associated with the host macronucleus. With its electron-dense cytoplasm and a distinct halo surrounding the cell, it is easily distinguishable from the second smaller symbiont, “CandidatusFokinia cryptica,” whose cytoplasm is electron lucid, lacks a halo, and is always surrounded by a symbiontophorous vacuole. For molecular characterization, the small-subunit rRNA genes were sequenced and used for taxonomic assignment as well as the design of species-specific oligonucleotide probes. Phylogenetic analyses revealed that “CandidatusBealeia paramacronuclearis” clusters with the so-called “basal”Rickettsiales, and “CandidatusFokinia cryptica” belongs to “CandidatusMidichloriaceae.” We obtained tree topologies showing a separation ofRickettsialesinto at least two groups: one represented by the familiesRickettsiaceae,Anaplasmataceae, and “CandidatusMidichloriaceae” (RAM clade), and the other represented by “basalRickettsiales,” including “CandidatusBealeia paramacronuclearis.” Therefore, and in accordance with recent publications, we propose to limit the orderRickettsialesto the RAM clade and to raise “basalRickettsiales” to an independent order,Holosporalesord. nov., insideAlphaproteobacteria, which presently includes four family-level clades. Additionally, we define the family “CandidatusHepatincolaceae” and redefine the familyHolosporaceae.IMPORTANCEIn this paper, we provide the characterization of two novel bacterial symbionts inhabiting the sameParameciumhost (Ciliophora, Alveolata). Both symbionts belong to “traditional”Rickettsiales, one representing a new species of the genus “CandidatusFokinia” (“CandidatusMidichloriaceae”), and the other representing a new genus of a “basal”Rickettsiales. According to newly characterized sequences and to a critical revision of recent literature, we propose a taxonomic reorganization of “traditional”Rickettsialesthat we split into two orders:Rickettsiales sensu strictoandHolosporalesord. nov. This work represents a critical revision, including new records of a group of symbionts frequently occurring in protists and whose biodiversity is still largely underestimated.

scholarly journals Phylogenetic relationships of the family Tarumaniidae (Characiformes) based on nuclear and mitochondrial data

2018 ◽  
Vol 16 (3) ◽  
Author(s):  
Dahiana Arcila ◽  
Paulo Petry ◽  
Guillermo Ortí
Keyword(s):  
Bayesian Inference ◽  
Maximum Likelihood ◽  
South America ◽  
Sister Group ◽  
The Other ◽  
Molecular Analyses ◽  
Mitochondrial Data ◽  
The Family ◽  
Commercially Important ◽  
Group Relationships

ABSTRACT Characiformes is an order of freshwater fishes that includes many commercially important and emblematic species from South America and Africa, such as the popular piranhas, hatchetfishes, African tiger fishes and tetras. The order is split into two suborders with a total of 24 families, 282 genera and ca. 2,100 species. Here, we present an expanded phylogeny of characiform fishes, including data for 520 species and three genes (12S, 16S and RAG1), and the recently described family Tarumaniidae, which has not been examined by previous molecular analysis. Although our genetic coverage is limited to three gene fragments, the tree inferred based on maximum likelihood and Bayesian inference supports the monophyly of all characiform families and is largely congruent with results from recent studies that sampled less taxa but more genes. Also in agreement with a morphological hypothesis, our results strongly support the sister-group relationships between the family Tarumaniidae and Erythrinidae. Based on our results and that of the other molecular analyses, we propose a revised circumscription of the superfamily Erythrinoidea to include the families Tarumaniidae and Erythrinidae only.

First records of Parergodrilus heideri (Annelida: "Polychaeta") from North America

Zootaxa ◽  
2012 ◽  
Vol 3498 (1) ◽  
pp. 81 ◽  
Author(s):  
JIŘÍ SCHLAGHAMERSKÝ ◽  
LEE E. FRELICH
Keyword(s):  
Body Size ◽  
North America ◽  
Small Body ◽  
The Other ◽  
Small Body Size ◽  
Free Living ◽  
Soil Mesofauna ◽  
The Family ◽  
Terrestrial Habitats

Parergodrilus heideri Reisinger, 1925 is one of two species of the family Parergodrilidae (together with the marine litoral, interstitial species Stygocapitella subterranea Knöllner, 1934) and one of only two truly soil-dwelling “polychaetes” (the other being Hrabeiella periglandulata Pižl and Chalupský, 1984) that are predominantly known from terrestrial habitats (Reisinger 1925, 1960; Römbke and Jans 1991; Chalupský 1992; Graefe 1993; Rota 1997, 1998; Purschke 1999; Rota et al. 2001; Beylich and Graefe 2007; Martinez-Ansemil and Parapar 2009; Rota et al. 2010). Due to its small body size (adults up to 1 mm) and sensitivity to dessication, the species has usually been found by researchers using some type of wet extraction for soil mesofauna, such as enchytraeids and free-living flatworms (“turbellarians”). However, due to its similar chaetae, Parergodrilus heideri can be easily mistaken for a freshly hatched enchytraeid, even by enchytraeid specialists without experience with this species.

Systematic status of the caridean families Gnathophyllidae Dana and Hymenoceridae Ortmann (Crustacea : Decapoda): a preliminary examination based on nuclear rDNA sequences

2007 ◽  
Vol 21 (6) ◽  
pp. 613 ◽  
Author(s):  
M. Mitsuhashi ◽  
Y. W. Sin ◽  
H. C. Lei ◽  
T.-Y. Chan ◽  
K. H. Chu
Keyword(s):  
Phylogenetic Trees ◽  
18S Rrna ◽  
Rrna Genes ◽  
28S Rrna ◽  
Nuclear Rdna ◽  
Rdna Sequences ◽  
Preliminary Examination ◽  
The Family ◽  
Close Relationship ◽  
Paraphyletic Assemblage

The systematic positions of the caridean families Gnathophyllidae and Hymenoceridae are inferred based on analyses of nuclear 18S rRNA and 28S rRNA genes. The phylogenetic trees based on 18S rRNA and 28S rRNA from selected species of one genus of the family Gnathophyllidae, two genera of the family Hymenoceridae, one genus of the family Anchistioididae, eight genera of the subfamily Pontoniinae and five genera of the subfamily Palaemoninae show a close relationship between Hymenoceridae, Gnathophyllidae and Pontoniinae, with the last group constituting a paraphyletic assemblage. This result concurs with the morphology of maxilla in the first zoea, but not the shape of the third maxilliped in adults, based on which Gnathophyllidae and Hymenoceridae are treated as families. Molecular analysis supports the similarities in larval morphology between Hymenoceridae, Gnathophyllidae and Pontoniinae and therefore draws into question the familial status of the former two groups.

Phylogenetic analysis using rDNA reveals polyphyly of Oplophoridae (Decapoda:Caridea)

2010 ◽  
Vol 24 (2) ◽  
pp. 172 ◽  
Author(s):  
Tin-Yam Chan ◽  
Ho Chee Lei ◽  
Chi Pang Li ◽  
Ka Hou Chu
Keyword(s):  
Phylogenetic Analysis ◽  
18S Rrna ◽  
Morphological Characters ◽  
The Other ◽  
Rrna Genes ◽  
Deep Channel ◽  
The Family ◽  
Molecular Phylogenetic ◽  
18S Rrna Genes ◽  
Molar Process

Molecular phylogenetic analysis on nine of the ten genera in the caridean family Oplophoridae Dana, 1852, as well as 14 other caridean families using mitochondrial 16S and nuclear 18S rRNA genes, does not support the monophyletic status of Oplophoridae. Two disparate groups of oplophorids are revealed, with different morphological characters and ecology. It is proposed that the family Oplophoridae is restricted to the three genera Oplophorus, Systellaspis and Janicella. These three genera tend to be distributed in shallower water than the other oplophorid genera, and can also be distinguished from them by certain morphological characters. They have a thicker integument, superficial cuticular photophores and larger eyes, and the molar process of their mandibles is greatly reduced or bears a deep channel. The family Acanthephyridae Bate, 1888 is resurrected for the other seven genera, which are generally distributed in deeper water and are characterised by red soft integument, no cuticular photophores, smaller eyes and well-developed molar process of the mandibles without a deep channel. The relationships between these two families and other caridean families could not be clearly resolved in this study.

scholarly journals First Description of Ecomorphotypes in Seal Subfamilies

2020 ◽  
Vol 3 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Rahmat SJ
Keyword(s):  
Body Size ◽  
Morphological Characters ◽  
The Other ◽  
Fossil Species ◽  
The Family ◽  
Similarities And Differences ◽  
The Many ◽  
First Time ◽  
Group Species ◽  
Dietary Data

The Family Phocidae consists of four subfamilies, with ecomorphs known only in representatives of the subfamily Phocinae. This study demonstrates that ecological and morphological characters of the other three subfa milies Cystophorinae, Devinophocinae, Monachinae) do not fit precisely into the previously described ecomorphs for Phocinae. These groupings are based on recent seals, but can also be extrapolated to fossil seals based on morphology and probable ecologica l preferences. The separation of taxa by combining morphological, ecological and dietary data is extremely important for demonstrating similarities and differences in both fossil and modern representatives of seals of the Family Phocidae, straying away fro m normal alpha and beta systematics that group species based only on taxonomic relationships. Due to the fragility of cranial remains, the three most commonly found bones (mandible, humerus, femur) are used to group species. Modern seals have specific morp hological features and ecological distinctions (diving depths, environment, diet, body size) similar to those of fossil species, providing a rationale for associating the many dissociated fossil elements. For the first time, seals of all phocids subfamilie s are divided into their corresponding ecomorphs.

Evolutionary relationships of the bivalve family Thyasiridae (Mollusca: Bivalvia), monophyly and superfamily status

2007 ◽  
Vol 87 (2) ◽  
pp. 565-574 ◽  
Author(s):  
John D. Taylor ◽  
Suzanne T. Williams ◽  
Emily A. Glover
Keyword(s):  
Fossil Record ◽  
18S Rrna ◽  
Rrna Genes ◽  
Symbiotic Bacteria ◽  
Evolutionary Relationships ◽  
Marine Bivalve ◽  
28S Rrna ◽  
Molecular Analyses ◽  
The Family ◽  
Basal Position

Molecular analyses of 13 species of the marine bivalve family Thyasiridae, using sequences from 18S rRNA and 28S rRNA genes, showed that the family is monophyletic despite the anatomical disparity and inclusion of both chemosymbiotic and asymbiotic species. This new analysis also confirmed that the three families (Thyasiridae, Lucinidae and Ungulinidae), previously included in the Lucinoidea, were not closely related. Four species of Ungulinidae grouped within a clade containing Veneridae, Arcticidae and Mactridae. In relation to a range of other heterodont bivalves, Thyasiridae occupied a near basal position, apart from a clade comprising Carditidae/Astartidae/Crassatellidae. The earliest thyasirid recognized in the fossil record is a species from the Lower Cretaceous of England. Within the Thyasiridae, some groups can be identified but relations between these are weakly supported. Amongst the taxa analysed, those with symbiotic bacteria and two ctenidial demibranchs belong to at least three groups, while there is some support for a clade of asymbiotic taxa with single demibranchs. In recognition of the monophyletic status of the Thyasiridae, distinct from all other heterodont bivalves, we elevate the rank to superfamily Thyasiroidea.

Molecular characterisation and phylogenetic relationships of sedentary nematodes of the genus Meloinema Choi & Geraert, 1974 (Nematoda: Tylenchida)

Nematology ◽  
2020 ◽  
pp. 1-9
Author(s):  
Sergei A. Subbotin ◽  
Donggeun Kim
Keyword(s):  
Phylogenetic Trees ◽  
18S Rrna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
28S Rrna ◽  
Molecular Characterisation ◽  
Sister Relationship ◽  
The Family ◽  
18S Rrna Genes ◽  
Relationship Of

Summary Molecular characterisation of two species of Meloinema: M. chitwoodi from Oregon, USA, and M. odesanens from South Korea, is given based on the partial 18S rRNA, the D2-D3 of 28S rRNA, ITS rRNA, and COI gene sequences. In the phylogenetic trees, Meloinema clustered with Meloidogyne, in a basal position and more closely with Meloidogyne indica and M. nataliei. The Shimodaira-Hasegawa (SH) maximum likelihood testing of an alternative topology with two gene fragments (D2-D3 of 28S rRNA and 18S rRNA genes) did not reject a sister relationship of Meloidogyne and Meloinema. Molecular results confirmed the view of Siddiqi (2000) that Meloidogyne and Meloinema evolved from a Pratylenchidae-type ancestor. The clade Meloinema + Meloidogyne + Nacobbus was rejected by the SH test of the D2-D3 of 28S rRNA gene sequence dataset. The molecular results suggested that the genus Nacobbus should be placed not in the Meloidogynidae, but in a separate subfamily, the Nacobbinae, under the family Pratylenchidae.

scholarly journals Phylogenetic analyses of ribosomal transcription units from Haplorchis taichui and H. pumilio species of Heterophyidae (Platyhelminthes: Opisthorchiata)

2021 ◽  
Vol 18 (4) ◽  
pp. 643-652
Author(s):  
Le Thi Viet Ha ◽  
Nguyen Thi Khue ◽  
Dong Van Quyen ◽  
Le Thanh Hoa
Keyword(s):  
Phylogenetic Tree ◽  
Phylogenetic Analyses ◽  
28S Rdna ◽  
Rrna Genes ◽  
28S Rrna ◽  
Coding Sequence ◽  
Rdna Sequences ◽  
The Family ◽  
28S Rdna Sequences ◽  
Haplorchis Taichui

Heterophyidiasis caused by minute intestinal flukes becomes of public concern in many countries worldwide. Haplorchis taichui and H. pumilio, belonging to the family Heterophyidae (Platyhelminthes: Trematoda) are two of many infecting humans and commonly found in Vietnam. Sequence study of these two small intestinal flukes is still very limited, hence we need more prospective markers for taxonomic identification and classification. This study provides complete coding sequence of the ribosomal transcription units (rTU) from H. taichui and H. pumilio (Vietnamese samples) and demonstrates the use of complete 28S rDNA sequences for phylogenetic analysis.The complete coding sequence of the rTU (from 5' 18S to 3' 28S), consisting of complete 18S, ITS-1, 5.8S, ITS2 and complete 28S rRNA genes and spacers, from H. taichui (7,268 bp) and H. pumilio (7,416 bp) from human hosts in Vietnam, were determined and annotated. The 18S and 5.8S genes of both species were of the same length (1,992 bp/18S, 160 bp/5.8S), but 28S genes differed (3,875 bp/H. taichui and 3,870 bp/H. pumilio). ITS-1 in H. taichui (797 bp) and ITS-2 in H. pumilio (280 bp) do not contain tandem repeat units (TRUs), while ITS-1 in H. pumilio (1,106 bp) contains 3 TRUs of 136 bp/each and 2 TRUs of 116 bp/each and ITS-2 in H. taichui (444 bp) contain 3 TRUs (83–85 bp/each). A phylogenetic tree inferred from the alignment of complete 28S rDNA sequences of 32 trematode strains/species, including 2 Vietnamese Haplorchis spp. and 24 species of 8 families in the suborders Xiphidiata (families Nanophyetidae, Paragonimidae, Collyriclidae), Opisthorchiata (Heterophyidae, Opisthorchiidae), and Echinostomata (Echinostomatidae, Fasciolidae).  and Schistosoma japonicum of the family Schistosomatidae is used as an outgroup. The topology of the phylogenetic tree clearly confirmed the status of the Vietnamese H. taichui and H. pumilio species. These species gathered in a group (in the family Heterophyidae) clearly identified in the position of "sister” group to those in the family Opisthorchiidae (suborder Opisthorchiata, superfamily Opisthorchioidea).

Sign in / Sign up

Export Citation Format

Share Document