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1.
Commun Biol ; 3(1): 106, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144383

RESUMO

Ocean deoxygenation driven by global warming and eutrophication is a primary concern for marine life. Resistant animals may be present in dead zone sediments, however there is lack of information on their diversity and metabolism. Here we combined geochemistry, microscopy, and RNA-seq for estimating taxonomy and functionality of micrometazoans along an oxygen gradient in the largest dead zone in the world. Nematodes are metabolically active at oxygen concentrations below 1.8 µmol L-1, and their diversity and community structure are different between low oxygen areas. This is likely due to toxic hydrogen sulfide and its potential to be oxidized by oxygen or nitrate. Zooplankton resting stages dominate the metazoan community, and these populations possibly use cytochrome c oxidase as an oxygen sensor to exit dormancy. Our study sheds light on mechanisms of animal adaptation to extreme environments. These biological resources can be essential for recolonization of dead zones when oxygen conditions improve.

2.
Zootaxa ; 4695(2): zootaxa.4695.2.7, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31719358

RESUMO

Specimens of a population of Cribronema collected in Cameroon are described as Cribronema sturhani sp. n. The new species resembles C. cribrum, which is the only species described in the genus, but it differs from it by the following features: a somewhat shorter tail in the females, longer spermatheca and postuterine vulval sac, tail terminus in females pointed vs. harpoon-shaped, and presence vs. absence of males.


Assuntos
Nematoides , Rabditídios , Tylenchida , Animais , Camarões , Feminino , Masculino
3.
Biodivers Data J ; 7: e46545, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31719779

RESUMO

Background: The genus Campylaimus is a broadly distributed but relatively uncommon genus of marine and brackish nematodes with 20 nominal species and one nomen nudum. Many species descriptions and redescriptions are based on very few (single) individuals, which limits our understanding of inter- and intra-specific variability and morphology-based species boundaries. New information: Two new species were found in the Skagerrak off the west coast of Sweden. Campylaimus triclados sp. n. is characterised by body 0.59-0.69 mm long; cuticle without longitudinal striation; anteriormost edge of the amphid anterior to the oral opening; dorsal limb of the amphid equal to 1.6-2.5 labial region diameters in male, 1.9 labial region diameters in female; ventral limb of the amphid extends towards anterior part of the intestine in male and midpharynx in female, 4.3-5.5 times the length of the dorsal limb in male and 2.2-2.8 times the length of the dorsal limb in female; ventral limb of the amphid is as wide as the dorsal limb; interamphideal space extends further than the posterior end of the dorsal limb but not reaching the posterior end of the ventral limb; secretory-excretory pore opens posterior to the cardia; spicules 19-24 µm long; two precloacal supplements; tail equal to 4.3-5.6 anal body diameters in length, with conoid terminal part. Campylaimus longispiculus sp. n. is characterised by body 0.56-0.65 mm long; cuticle without longitudinal striation; anteriormost edge of the amphid anterior to the oral opening; dorsal limb of the amphid equal to 1.8-2.1 labial region diameters in male; ventral limb of the amphid extends towards anterior part of the intestine in male, 2.8-3.5 times the length of the dorsal limb in male; ventral limb of the amphid is as wide as the dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to the cardia; spicules 28-35 µm long; two precloacal supplements; tail equal to 4.9-5.3 anal body diameters in length, with clavate terminal part. In addition, following nine species are new records for the fauna of Sweden: Campylaimus amphidialis, C. inaequalis, C. lefeverei, C. minutus, C. orientalis, C. rimatus, C. siwaschensis, C. striatus and C. tkatchevi.

4.
Zootaxa ; 4651(2): zootaxa.4651.2.8, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31716914

RESUMO

Populations of three rare species of the genus Acrobeles are described from the Kelso Dunes area, Mojave National Preserve, southern California. One population is identified as belonging to A. undulatus and is compared with the type population from Venezuela and one population from Iran. Males of this species are described for the first time. Another population identified as belonging to A. ornatus is compared with the type population from Colorado, USA. Specimens identified as belonging to A. dimorphus are compared with the type population from Namibia. Descriptions of the new material add morphological data important for species identification, broaden the diagnosis of Acrobeles and increase the distribution patterns of these three species.


Assuntos
Rabditídios , Animais , California , Colorado , Irã (Geográfico) , Masculino , Namíbia , Venezuela
5.
BMC Evol Biol ; 19(1): 121, 2019 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-31195978

RESUMO

BACKGROUND: Nematodes are among the most diverse and abundant metazoans on Earth, but research on them has been biased toward parasitic taxa and model organisms. Free-living nematodes, particularly from the clades Enoplia and Dorylaimia, have been underrepresented in genome-scale phylogenetic analyses to date, leading to poor resolution of deep relationships within the phylum. RESULTS: We supplemented publicly available data by sequencing transcriptomes of nine free-living nematodes and two important outgroups and conducted a phylum-wide phylogenomic analysis including a total of 108 nematodes. Analysis of a dataset generated using a conservative orthology inference strategy resulted in a matrix with a high proportion of missing data and moderate to weak support for branching within and placement of Enoplia. A less conservative orthology inference approach recovered more genes and resulted in higher support for the deepest splits within Nematoda, recovering Enoplia as the sister taxon to the rest of Nematoda. Relationships within major clades were similar to those found in previously published studies based on 18S rDNA. CONCLUSIONS: Expanded transcriptome sequencing of free-living nematodes has contributed to better resolution among deep nematode lineages, though the dataset is still strongly biased toward parasites. Inclusion of more free-living nematodes in future phylogenomic analyses will allow a clearer understanding of many interesting aspects of nematode evolution, such as morphological and molecular adaptations to parasitism and whether nematodes originated in a marine or terrestrial environment.


Assuntos
Genômica , Nematoides/classificação , Nematoides/genética , Filogenia , Animais , Evolução Molecular , Funções Verossimilhança
6.
Zootaxa ; 4514(3): 438-444, 2018 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-30486208

RESUMO

Specimens of Drilocephalobus moldavicus are described from the Kelso Dunes area, Mojave National Preserve, southern California. This is the first record of the genus in North America. The specimens of this population are characterized by a body length of 322-417 µm in females and 403 µm in the male; cuticle finely annulated; lateral field with five incisures, extending to phasmid and two incisures extending almost to tail terminus in both sexes; lip region helmet-shaped, offset from body contour; lips amalgamated; stoma with thin walls lacking sclerotizations; pharynx without distinct divisions, cylindrical, widening slightly at about 1/3 of its length and basally, without valves; spermatheca 14-19 µm long; postvulval uterine sac 25-27 µm long; spicules 23 µm long; and female tail conoid-elongate with rounded terminus.


Assuntos
Rabditídios , Tylenchida , Animais , California , Feminino , Masculino
7.
R Soc Open Sci ; 4(8): 170315, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28878981

RESUMO

Precision and reliability of barcode-based biodiversity assessment can be affected at several steps during acquisition and analysis of data. Identification of operational taxonomic units (OTUs) is one of the crucial steps in the process and can be accomplished using several different approaches, namely, alignment-based, probabilistic, tree-based and phylogeny-based. The number of identified sequences in the reference databases affects the precision of identification. This paper compares the identification of marine nematode OTUs using alignment-based, tree-based and phylogeny-based approaches. Because the nematode reference dataset is limited in its taxonomic scope, OTUs can only be assigned to higher taxonomic categories, families. The phylogeny-based approach using the evolutionary placement algorithm provided the largest number of positively assigned OTUs and was least affected by erroneous sequences and limitations of reference data, compared to alignment-based and tree-based approaches.

9.
Zootaxa ; 4232(4): zootaxa.4232.4.1, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28264348

RESUMO

The Swedish marine nematologist Carl Allgén (1886-1960) published 185 scientific papers on parasitic, terrestrial, limnic and especially marine nematodes between 1921 and 1960. Among them are also some papers on species of suctorians found mostly on desmodorid nematodes. He described about 70 new genera and over 800 new species and subspecies of nematodes. Allgén left a large collection of nematodes to the Swedish Museum of Natural History in Stockholm and it is now deposited in the invertebrate collection of the Zoology department. The collection comprises about 4500 slides in total, with about 310 slides containing type specimens collected from the Arctic to Antarctica. Allgén's publications have to a large extent been ignored by scientists working on marine nematodes, likely because of the poor quality of many of his species descriptions. The authors want to remind the scientific community about the existence of Allgén's collection, its availability for study and its importance for nematode taxonomy and systematics. A complete list of Allgén's publications, a list of all species described by him, and a list of type material available is presented.


Assuntos
Zoologia/história , Animais , Regiões Árticas , História do Século XIX , História do Século XX , História Natural , Nematoides , Suécia
10.
Biodivers Data J ; (4): e10021, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27932919

RESUMO

BACKGROUND: Metabarcoding is becoming a common tool used to assess and compare diversity of organisms in environmental samples. Identification of OTUs is one of the critical steps in the process and several taxonomy assignment methods were proposed to accomplish this task. This publication evaluates the quality of reference datasets, alongside with several alignment and phylogeny inference methods used in one of the taxonomy assignment methods, called tree-based approach. This approach assigns anonymous OTUs to taxonomic categories based on relative placements of OTUs and reference sequences on the cladogram and support that these placements receive. NEW INFORMATION: In tree-based taxonomy assignment approach, reliable identification of anonymous OTUs is based on their placement in monophyletic and highly supported clades together with identified reference taxa. Therefore, it requires high quality reference dataset to be used. Resolution of phylogenetic trees is strongly affected by the presence of erroneous sequences as well as alignment and phylogeny inference methods used in the process. Two preparation steps are essential for the successful application of tree-based taxonomy assignment approach. Curated collections of genetic information do include erroneous sequences. These sequences have detrimental effect on the resolution of cladograms used in tree-based approach. They must be identified and excluded from the reference dataset beforehand.Various combinations of multiple sequence alignment and phylogeny inference methods provide cladograms with different topology and bootstrap support. These combinations of methods need to be tested in order to determine the one that gives highest resolution for the particular reference dataset.Completing the above mentioned preparation steps is expected to decrease the number of unassigned OTUs and thus improve the results of the tree-based taxonomy assignment approach.

11.
Biodivers Data J ; (4): e10647, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27932928

RESUMO

BACKGROUND: The diversity of organisms is being commonly accessed using metabarcoding of environmental samples. Reliable identification of barcodes is one of the critical steps in the process and several taxonomy assignment methods were proposed to accomplish this task, including alignment-based approach that uses Basic Local Alignment Search Tool (BLAST) algorithm. This publication evaluates the variability of 5' end of 18S rRNA barcoding region as expressed by similarity scores (alignment score and identity score) produced by BLAST, and its impact on barcode identification to family-level taxonomic categories. NEW INFORMATION: In alignment-based taxonomy assignment approach, reliable identification of anonymous OTUs to supraspecific taxa depends on the correct application of similarity thresholds. Since various taxa show different level of genetic variation, practical application of alignment-based approach requires the determination and use of taxon-specific similarity thresholds.

12.
Syst Parasitol ; 93(9): 877-898, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27743233

RESUMO

A new species of Alloionema Schneider, 1859, A. similis n. sp., and the known species A. appendiculatum Schneider, 1859 were isolated from cadavers of invasive slugs in California. Both species are described based on morphology, morphometrics and molecular data. Alloionema similis n. sp. is morphologically very similar to A. appendiculatum but can be distinguished by a more posterior position of the excretory pore in the Kleinform females and longer tail in the Kleinform males. Substantial differences between the two species are, however, found in both 18S and 28S rDNA sequences. Sequence analysis revealed unambiguous autapomorphies in nucleotide sequence and secondary structure of rRNA genes, separating A. appendiculatum and A. similis n. sp. Molecular phylogenies were inferred from concatenated secondary-structure based multiple sequence alignments of nearly complete 18S and the D1-D3 domains of the 28S rRNA genes. Phylogenetic analyses placed these two species as sister taxa in a monophyletic clade, separately from Neoalloionema tricaudatum Ivanova, Pham Van Luc & Spiridonov, 2016 and N. indicum Nermut, Puza & Mrácek, 2016.


Assuntos
Gastrópodes/parasitologia , Rabditídios/classificação , Rabditídios/genética , Animais , California , Feminino , Variação Genética , Masculino , Filogenia , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Rabditídios/anatomia & histologia , Rabditídios/isolamento & purificação , Especificidade da Espécie
13.
Biodivers Data J ; (4): e7768, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26935175

RESUMO

[This corrects the article DOI: 10.3897/bdj.2.e1165.].

14.
Zootaxa ; 4034(1): 1-44, 2015 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-26624429

RESUMO

The genus Deontolaimus de Man, 1880 is revised and the genus Camacolaimus de Man, 1889 is considered a junior synonym of Deontolaimus based on re-examination of type material of Camacolaimus tardus de Man, 1889 and C. barbatus Warwick, 1970. Two known and three new species of Deontolaimus are described from bottom sediments collected in marine habitats of Sweden: Deontolaimus uniformis (Cobb, 1920) comb. n., D. longicauda (de Man, 1922) comb. n., Deontolaimus catalinae sp. n., D. paraguillei sp. n. and Deontolaimus timmi sp. n. Deontolaimus catalinae sp. n. is characterized by body length of 1.3-1.7 mm; anterior-most somatic sensilla located short distance posterior to amphid; cephalic sensilla equal to 0.2 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located in front of cephalic sensilla bases; excretory pore located short distance posterior to onchiostyle base; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to middle of body, tubular supplements absent; spicules 36-40 µm long; and didelphic female reproductive system. Deontolaimus paraguillei sp. n. is characterized by body length of 1.4-1.8 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located at level with cephalic sensilla bases; excretory pore located just posterior to nerve ring level; onchiostyle with bluntly rounded tip and subcylindrical body; male with alveolar supplements extending from anterior end to about three body diameters in front of cloaca, tubular supplements absent; spicules 42-46 µm long; and didelphic female reproductive system. Deontolaimus timmi sp. n. is characterized by body length of 0.7-0.9 mm; anterior-most somatic sensilla located at level with onchiostyle; cephalic sensilla equal to 0.2-0.3 labial region diameter in length; amphidial fovea ventrally-unispiral with one turn, located just in front of cephalic sensilla bases; excretory pore located just posterior to nerve ring level; onchiostyle with triangular tip with bluntly rounded apex and strongly sclerotized dorsal edge, and subcylindrical body; male with alveolar supplements extending from anterior end to anterior part of intestine, tubular supplements absent; spicules 28 µm long; and didelphic female reproductive system. The following nomenclatorial changes are proposed: genera Acontiolaimus Filipjev, 1918, Camacolaimoides De Coninck & Schuurmans Stekhoven, 1933, Camacolaimus de Man, 1889, Digitonchus Cobb, 1920 and Ypsilon Cobb, 1920 are synonimized with the genus Deontolaimus de Man, 1880; Camacolaimus reykjanesi De Coninck, 1943 and Camacolaimus glauxicola Allgén, 1951a are considered junior synonyms of Deontolaimus papillatus de Man, 1880; Camacolaimus barbatus apud Pastor de Ward, 1984 is described as the separate species Deontolaimus catalinae sp. n.; Camacolaimus tardus apud Lorenzen, 1969 is considered to be the separate species Deontolaimus lorenzeni nom. n.; Camacolaimus tardus apud Timm, 1963 is described as the separate species Deontolaimus timmi sp. n.; Camacolaimus barbatus Warwick, 1970 is considered a junior synonym of Deontolaimus tardus (de Man, 1889) comb. n.; Camacolaimus parvus Timm, 1961 is transferred to the genus Deontolaimus as D. parvus (Timm, 1961) comb. n.; Digitonchus cylindricaudatus Chitwood, 1951 is transferred to the genus Deontolaimus as D. cylindricaudatus (Chitwood, 1951) comb. n.; Ypsilon exile Cobb, 1920 is transferred to the genus Deontolaimus as D. exilis (Cobb, 1920) comb. n.; Camacolaimus guillei de Bovee, 1977 is transferred to the genus Deontolaimus as D. guillei (de Bovee, 1977) comb. n.; Camacolaimus longicauda de Man, 1922 is transferred to the genus Deontolaimus as D. longicauda (de Man, 1922) comb. n.; Camacolaimus monhystera Gerlach, 1967 is transferred to the genus Deontolaimus as D. monhystera (Gerlach, 1967) comb. n.; Camacolaimus pontollittoralis Uzunov, 1977 is transferred to the genus Deontolaimus as D. pontollittoralis (Uzunov, 1977) comb. n.; Camacolaimus praedator de Man, 1922 is transferred to the genus Deontolaimus as D. praedator (de Man, 1922) comb. n.; Camacolaimus prytherchi Chitwood, 1935 is transferred to the genus Deontolaimus as D. prytherchi (Chitwood, 1935) comb. n.; Camacolaimus tardus de Man, 1889 is transferred to the genus Deontolaimus as D. tardus (de Man, 1889) comb. n.; Camacolaimus trituberculatus Blome, 1982 is transferred to the genus Deontolaimus as D. trituberculatus (Blome, 1982) comb. n.; and Digitonchus uniformis Cobb, 1920 is transferred to the genus Deontolaimus as D. uniformis (Cobb, 1920) comb. n. A taxonomic review and identification key for species of the genus Deontolaimus are also given.


Assuntos
Adenofórios/classificação , Adenofórios/anatomia & histologia , Adenofórios/crescimento & desenvolvimento , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Suécia
15.
Biodivers Data J ; (3): e5738, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26379464

RESUMO

BACKGROUND: The genus Aegialoalaimus de Man, 1907 includes 12 nominal species, of which three species are considered valid, two species were transferred to other genera and seven species have uncertain taxonomic status. NEW INFORMATION: New species, Aegialoalaimus bratteni sp. n. was found in Skagerrak off the west coast of Sweden. It is particularly characterized by the 1.5-1.8 mm long body, short papilliform cephalic sensilla, excretory pore opening just posterior to nerve ring level, spicules that are straight in shape, supplements and gubernaculum absent, separating it from other valid species of the genus. It can be further differentiated from Aegialoalaimus elegans in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.8-1.3 mm in A. elegans), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 34 µm long in A. elegans), absence of precloacal supplements (vs seven-eight in A. elegans), absence of gubernaculum (vs present in A. elegans); from A. setosa in having shorter tail (c´=2.6-3.1 in A. bratteni sp. n. vs c´=4.2 in A. setosa), shorter cephalic sensilla (0.5-1.0 µm in A. bratteni sp. n. vs 9 µm in A. setosa), shape and size of spicules (straight and 22-29 µm long in A. bratteni sp. n. vs arcuate and 40-45 µm long in A. setosa), absence of precloacal supplements (vs eight in A. setosa), absence of gubernaculum (vs present in A. setosa); from A. leptosoma in having longer body (1.5-1.8 mm in A. bratteni sp. n. vs 0.5-0.7 mm in A. leptosoma) and other measurements, shape of spicules (straight in A. bratteni sp. n. vs arcuate in A. leptosoma), absence of precloacal supplements (vs three-five in A. leptosoma), absence of gubernaculum (vs present in A. leptosoma). Type specimens of Aegialoalaimus cylindricauda Allgén, 1933 and A. paratenuicaudatus Allgén, 1959 are redescribed and taxonomic status of these two species is re-evaluated. A taxonomic review, tabular compendium and identification key for species of the genus Aegialoalaimus are also given.

16.
Zootaxa ; 3955(1): 83-100, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25947838

RESUMO

Three known and two new species of Leptolaimoides are described from bottom sediments collected in Skagerrak off the west coast of Sweden. The following known species are redescribed: Leptolaimoides haploopis Jensen, 1978, L. tubulosus Vitiello, 1971 and L. hexatubulosus Hoang Lai-Phu et al., 2009. Leptolaimoides filicaudatus sp. n. is characterised by the 431-543 µm long body; cephalic sensilla papilliform; amphid 23-26 µm long, located 9-10 µm from anterior end; first body pore located 35-37 µm from anterior end; lateral field simple along most of body, areolated on tail, arising 36-40 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male without tubular and without alveolar supplements; spicules arcuate and 16 µm long. Leptolaimoides leptomicron sp. n. is characterised by the 776-847 µm long body; cephalic sensilla papilliform; amphid 15-17 µm long, located 9-13 µm from anterior end; first body pore located 40-46 µm from anterior end; lateral field areolated, arising 26-28 µm from anterior end; female without supplements, vagina without pars refringens, vulva midventral; male with three tubular and without alveolar supplements, spicules arcuate and 28-29 µm long. The diagnosis of the genus Leptolaimoides is emended and a tabular compendium and dichotomous identification key to species of the genus Leptolaimoides are provided.


Assuntos
Nematoides/classificação , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Masculino , Nematoides/anatomia & histologia , Nematoides/crescimento & desenvolvimento , Tamanho do Órgão , Suécia
17.
Zootaxa ; 3911(4): 521-46, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25661628

RESUMO

Four known and one new species of Onchium are described from bottom sediments collected in Skagerrak off the west coast of Sweden. The following known species are redescribed: Onchium ocellatum Cobb, 1920, O. metocellatum Wieser, 1956, O. parocellatum (Allgén, 1940) and O. robustum Gerlach, 1965. Onchium longispiculum sp. n. is characterised by the 1.34-1.77 mm long body, anterior body end without cephalic capsule, anteriormost somatic sensilla located posterior to onchiostyle base, ocelli absent, excretory pore located at basis of lips, onchiostyle uniformly cylindrical, alveolar supplements indistinct, tubular supplements absent, spicules arcuate and 44-65 µm long. The new species has a unique set of characters (absence of developed ocelli and very long somewhat asymmetrical spicules) separating it from all other known species of the genus Onchium. The following nomenclatorial changes are proposed: O. conicaudatum (Allgén, 1935) is considered a junior synonym of O. metocellatum; O. conicaudatum apud Wieser, 1951 is considered a synonym of O. minutum Kito, 1981. The diagnosis of the genus Onchium is emended and a tabular compendium and dichotomous identification key to species of the genus Onchium are provided.


Assuntos
Adenofórios/classificação , Adenofórios/anatomia & histologia , Adenofórios/crescimento & desenvolvimento , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Suécia
18.
J Nematol ; 47(4): 337-55, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26941463

RESUMO

Near-full-length 18S and 28S rRNA gene sequences were obtained for 33 nematode species. Datasets were constructed based on secondary structure and progressive multiple alignments, and clades were compared for phylogenies inferred by Bayesian and maximum likelihood methods. Clade comparisons were also made following removal of ambiguously aligned sites as determined using the program ProAlign. Different alignments of these data produced tree topologies that differed, sometimes markedly, when analyzed by the same inference method. With one exception, the same alignment produced an identical tree topology when analyzed by different methods. Removal of ambiguously aligned sites altered the tree topology and also reduced resolution. Nematode clades were sensitive to differences in multiple alignments, and more than doubling the amount of sequence data by addition of 28S rRNA did not fully mitigate this result. Although some individual clades showed substantially higher support when 28S data were combined with 18S data, the combined analysis yielded no statistically significant increases in the number of clades receiving higher support when compared to the 18S data alone. Secondary structure alignment increased accuracy in positional homology assignment and, when used in combination with paired-site substitution models, these structural hypotheses of characters and improved models of character state change yielded high levels of phylogenetic resolution. Phylogenetic results included strong support for inclusion of Daubaylia potomaca within Cephalobidae, whereas the position of Fescia grossa within Tylenchina varied depending on the alignment, and the relationships among Rhabditidae, Diplogastridae, and Bunonematidae were not resolved.

19.
Biodivers Data J ; (2): e1165, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25197239

RESUMO

WE PRESENT AN UPDATED LIST OF TERRESTRIAL AND FRESHWATER NEMATODES FROM ALL REGIONS OF THE ARCTIC, FOR WHICH RECORDS OF PROPERLY IDENTIFIED NEMATODE SPECIES ARE AVAILABLE: Svalbard, Jan Mayen, Iceland, Greenland, Nunavut, Northwest territories, Alaska, Lena River estuary, Taymyr and Severnaya Zemlya and Novaya Zemlya. The list includes 391 species belonging to 146 genera, 54 families and 10 orders of the phylum Nematoda.

20.
Zootaxa ; 3847(4): 576-82, 2014 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-25112360

RESUMO

A new species of Setostephanolaimus, S. tchesunovi sp. n., is described from bottom sediments collected in the Skagerrak and Gullmarn Fjord off the west coast of Sweden. It is characterised by 1.0-1.3 mm long body, outer labial setae 6.5-8.5 µm long, cephalic setae 9-11 µm long, subcephalic setae 4-6 µm long, transversely-oval amphid, female with monodelphic opisthodelphic reproductive system, male with 6-9 tubular and without alveolar supplements, spicules arcuate and 54-64 µm long, gubernaculum with dorsal apophysis. A tabular compendium and dichotomous identification key to species of the genus Setostephanolaimus are provided. 


Assuntos
Adenofórios/classificação , Adenofórios/anatomia & histologia , Adenofórios/crescimento & desenvolvimento , Distribuição Animal , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Animais , Tamanho Corporal , Ecossistema , Feminino , Masculino , Tamanho do Órgão , Suécia
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