Steinernema innovationi n. sp. (Panagrolaimomorpha: Steinernematidae), a new entomopathogenic nematode species from South Africa

2014 ◽  
Vol 89 (4) ◽  
pp. 415-427 ◽  
Author(s):  
H. Çimen ◽  
M.-M. Lee ◽  
J. Hatting ◽  
S. Hazir ◽  
S.P. Stock
Keyword(s):  
South Africa ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
Mitochondrial Gene ◽  
Tail Length ◽  
Nematode Species ◽  
Total Body Length ◽  
Morphological Data ◽  
Cross Hybridization ◽  
Molecular Sequence Data

AbstractMorphological and molecular sequence data were combined with cross-hybridization studies and used to identify a new Steinernema sp. from Free State, South Africa. Molecular and morphological data indicate that the new species belongs to the ‘glaseri-group’ of Steinernema spp. Key morphological diagnostic characters for S. innovationi n. sp. include the morphometric features of the third-stage infective juveniles: total body length = 1054 (1000–1103) μm, tail length = 108 (97–117) μm, location of the excretory pore = 88 (82–91) μm, and D% = 58 (54–63), E% = 115 (104–137) and H% = 43 (37–46). Additionally, the morphology of the spicules and gubernaculum of the first-generation males are considered key diagnostic traits. Steinernema innovationi n. sp. was also characterized by analysis of both rDNA and mitochondrial gene sequence data, which further indicate the uniqueness of this Steinernema species.

Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae): the hidden host of Photorhabdus asymbiotica (Enterobacteriaceae: γ-Proteobacteria)

2009 ◽  
Vol 83 (4) ◽  
pp. 309-320 ◽  
Author(s):  
K.L. Plichta ◽  
S.A. Joyce ◽  
D. Clarke ◽  
N. Waterfield ◽  
S.P. Stock
Keyword(s):  
New Species ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Its Region ◽  
Nematode Species ◽  
Diagnostic Features ◽  
Cross Hybridization ◽  
Group V ◽  
Terminal Set

AbstractA new entomopathogenic nematode species from Australia, Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae) is described. Morphological and molecular studies together with cross-hybridization tests indicated that this nematode represents a new undescribed species, closely related to members in the ‘indica-group’. However, the new species can be distinguished from other species in this genus by a combination of several qualitative and quantitative morphological traits. Key diagnostic features include: body size and excretory pore position of the third-stage infective juveniles; male bursa with a reduction of bursal rays, usually affecting the terminal set of papillae, with symmetrical or asymmetrical loss of one or two pairs; vulva of hermaphrodites more anteriorly located than in other species in the indica-group (V% average: 43), with non-protruding or slightly protruding lips, and longer tail length (average: 106 μm). The new species can be further characterized by molecular traits of sequence data from the internal transcribed spacer (ITS) region of ribosomal DNA. Additionally, the bacterial symbiont of this new species, Photorhabdus asymbiotica Kingscliff strain, was phenotypically characterized and compared with other P. asymbiotica strains. The Kingscliff strain revealed many characters not present in other strains of this species. We hypothesize that the newly found traits may contribute to the maintenance of this mutualistic association of the bacterium with its nematode host.

Steinernema khuongin. sp. (Panagrolaimomorpha, Steinernematidae), a new entomopathogenic nematode species from Florida, USA

2018 ◽  
Vol 93 (2) ◽  
pp. 226-241 ◽  
Author(s):  
S.P. Stock ◽  
R. Campos-Herrera ◽  
F.E. El-Borai ◽  
L.W. Duncan
Keyword(s):  
New Species ◽  
Sequence Data ◽  
Novel Species ◽  
Entomopathogenic Nematode ◽  
Biological Species ◽  
Morphological Data ◽  
Biological Species Concept ◽  
The Novel ◽  
Ecological Data ◽  
Cross Hybridization

AbstractIn this study, molecular (ribosomal sequence data), morphological and cross-hybridization properties were used to identify a newSteinernemasp. from Florida, USA. Molecular and morphological data provided evidence for placing the novel species into Clade V, or the ‘glaseri-group’ ofSteinernemaspp. Within this clade, analysis of sequence data of the rDNA genes, 28S and internal transcribed spacer (ITS), depicted the novel species as a distinctive entity and closely related toS. glaseriandS. cubanum.Additionally, cross-hybridization assays showed that the new species is unable to interbreed with either of the latter two species, reinforcing its uniqueness from a biological species concept standpoint. Key morphological diagnostic characters forS. khuongin. sp. include the mean morphometric features of the third-stage infective juveniles: total body length (average: 1066 μm), tail length (average: 65 μm), location of the excretory pore (average: 80.5 μm) and the values ofc(average: 16.4),D% (average: 60.5),E% (average: 126) andH% (average: 46.6). Additionally, males can be differentiated fromS. glaseriandS. cubanumby the values of several ratios:D% (average: 68),E% (average: 323) and SW% (average: 120). The natural distribution of this species in Florida encompasses both natural areas and citrus groves, primarily in shallow groundwater ecoregions designated as ‘flatwoods’. The morphological, molecular, phylogenetic and ecological data associated with this nematode support its identity as a new species in theS. glaseri-group.

Nematodes associated with terrestrial slugs from canola fields and ornamental nurseries in South Africa

Zootaxa ◽  
2017 ◽  
Vol 4312 (1) ◽  
pp. 194 ◽  
Author(s):  
ANNIKA PIETERSE ◽  
ANTOINETTE P. MALAN ◽  
LAURA M. KRUITBOS ◽  
WILLEM SIRGEL ◽  
JENNA L. ROSS
Keyword(s):  
South Africa ◽  
Sequence Data ◽  
Large Subunit ◽  
Morphological Characteristics ◽  
Nematode Species ◽  
First Record ◽  
Small Subunit ◽  
Western Cape ◽  
Molecular Sequence Data ◽  
Molecular Sequence

A survey of nematodes that use terrestrial slugs as definitive hosts, was conducted in canola fields and ornamental nurseries located in the Western Cape province of South Africa. A total of 3290 slugs were collected from 22 different sites. On the identification of the slugs, they were vivisected and examined for internal nematodes. After identifying the nematodes found, on the basis of their morphological characteristics, their identity was confirmed using molecular sequence data for the internal transcribed spacer (ITS-1, 5.8S, ITS-2), D2-D3 expansion segments of the large subunit (LSU or 28S) and small subunit (SSU or 18S) ribosomal DNA. Of the 22 sites investigated, 13 had nematodes present, with 8 % of the slugs being found to be infected with nematodes. Seven nematode species were confirmed, including Agfa flexilis, Angiostoma margaretae, Angiostoma sp. (SA1), Caenorhabditis elegans, mermithid sp. (SA1), Phasmarhabditis sp. (SA3) and Phasmarhabditis sp. (SA4). In addition, several Angiostoma spp. were also isolated, but could only be identified to genus level due to limited material. Of the seven confirmed species, four were previously undescribed. This is the first record of A. margaretae associating with Deroceras panormitanum, Deroceras reticulatum, Lehmannia valentiana and Oopelta polypunctata. Also, this is the first time that a mermithid has been found associating with molluscs in South Africa. 

scholarly journals Heterorhabditis noenieputensis n. sp. (Rhabditida: Heterorhabditidae), a new entomopathogenic nematode from South Africa

2012 ◽  
Vol 88 (2) ◽  
pp. 139-151 ◽  
Author(s):  
A.P. Malan ◽  
R. Knoetze ◽  
L. Tiedt
Keyword(s):  
South Africa ◽  
New Species ◽  
Internal Transcribed Spacer ◽  
Morphological Traits ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
The Body ◽  
Species Comparison ◽  
Citrus Orchard ◽  
A New Species

AbstractA new entomopathogenic nematode in the genus Heterorhabditis is described from South Africa, from two singular isolates found 1000 km from each other, from beneath a fig tree and in a citrus orchard, respectively. Morphological and molecular studies indicate both isolates to be the same and a new undescribed Heterorhabditis species. Comparison of sequences of the internal transcribed spacer (ITS) rDNA and the D2D3 region of the 28S rDNA gene with available sequences of other described species within the genus, indicate the two isolates as a new species. Phylogenetic analysis of the sequence data concerned placed the new species, H. noenieputensis n. sp., closest to H. indica and H. gerrardi in the indica-group. The new species, H. noenieputensis n. sp., is distinguished from other species in the genus by a combination of several morphological traits of the males and the infective juveniles (IJs). The new species differs from all other species previously described, as regards the body length of the IJs, except for H. indica and H. taysearae, in which the IJ is smaller. The IJ also differs from that of H. indica in the length of the oesophagus, the body diameter, the length of the tail and the E%. In addition, males of H. noenieputensis n. sp. differ from their closest relative, H. indica, in the position of the excretory pore, SW% and D%; and from H. gerrardi in the length of the oesophagus and SW%. The seventh pair of genital papillae of H. noenieputensis n. sp. are normally developed, while for H. indica they are often branched or swollen at the base, while 8 and 9 are usually absent in both species.

A revision of the planthopper genus Chionomus Fennah (Hemiptera: Fulgoroidea: Delphacidae)

Zootaxa ◽  
2020 ◽  
Vol 4811 (1) ◽  
pp. 1-63
Author(s):  
KATHRYN M. WEGLARZ ◽  
CHARLES R BARTLETT
Keyword(s):  
Mixed Model ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Mitochondrial Gene ◽  
Molecular Evidence ◽  
Additional Species ◽  
Molecular Sequence Data ◽  
Molecular Sequence ◽  
Original Definition ◽  
Definition Of

The planthopper genus Chionomus Fennah, 1971 (Hemiptera: Fulgoroidea: Delphacidae) currently includes three Neotropical species, removed from the polyphyletic genus Delphacodes Fieber, 1866. Morphological and molecular evidence further redefine Chionomus to include ten additional species (eight species removed from Delphacodes, two described as new, viz. Chionomus dolonus n. sp. and C. herkos n. sp.), with another four species synonymized. Phylogenetic analyses of morphological and molecular sequence data of the mitochondrial gene Cytochrome Oxidase I provide support for the monophyly of Chionomus. We use a mixed model Bayesian optimality criterion to define phylogenetic relationships among Chionomus and support paraphyly of the original definition of Chionomus (with respect to Delphacodes) and monophyly of the revised genus. 

Experimental induction of intraspecific morphometric variability in a single population of Halicephalobus cf. gingivalis may surpass total interspecific variability

Nematology ◽  
2013 ◽  
Vol 15 (5) ◽  
pp. 529-544 ◽  
Author(s):  
Pamela Fonderie ◽  
Hanne Steel ◽  
Tom Moens ◽  
Wim Bert
Keyword(s):  
New Species ◽  
Univariate Analysis ◽  
Age Groups ◽  
Tail Length ◽  
Nematode Species ◽  
Molecular Techniques ◽  
Morphological Data ◽  
Morphometric Study ◽  
Morphometric Characters ◽  
Adult Age

Although molecular techniques are revolutionising nematode taxonomy, morphological data still form the basis of nematode species descriptions. However, morphological characters show a natural variability that should be taken into account before describing new species. The current study presents the results of an elaborate morphometric study of Halicephalobus cf. gingivalis, including 15 measurements and 13 indices of 540 specimens, the progeny of a single parthenogenetic female and cultured under different temperature and food conditions and measured in different adult age groups, i.e., young adults with a developed vulva but before the onset of oviposition, adults laying eggs, and old, post-reproductive adults near the end of their life cycle. The morphometric characters were analysed using both univariate (analysis of variance) and multivariate (principal components and canonical discriminant analysis) techniques. The main results reveal that the morphometric characters most used in Halicephalobus identification keys have a huge variability within a single progeny, e.g., body length 1.9 times longer than the shortest or ratio VA/tail length 3.9 times larger than the smallest. This variability has a magnitude that has not been observed in nematodes before. Further, by changing the environmental factors, the morphometric characters are influenced to an extent that one could assign – with seemingly ‘statistical support’ – different ‘species’ of the genus to different subpopulations. With this experimental study we provide convincing elements to advocate an integrative taxonomic approach and to discourage the description of new species based only on morphometric differences.

Nematodes associated with terrestrial slugs in the Edmonton region of Alberta, Canada

2020 ◽  
Vol 94 ◽  
Author(s):  
T. Brophy ◽  
R.J. Mc Donnell ◽  
D.K. Howe ◽  
D.R. Denver ◽  
J.L. Ross ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Ribosomal Dna ◽  
Sequence Data ◽  
Nematode Species ◽  
Species Level ◽  
Molecular Sequence Data ◽  
Molecular Sequence ◽  
C Elegans ◽  
Facultative Parasite ◽  
Arion Rufus

Abstract A survey of nematodes associated with terrestrial slugs was conducted in residential gardens, nurseries, greenhouses and agricultural sites located in and around Edmonton, Alberta, Canada. A total of 2406 slugs were collected from 82 sites. Slugs were decapitated and cadavers were incubated for two weeks, with emerging nematodes removed and processed for identification. Nematodes were identified using molecular sequence data for the 18S ribosomal DNA. Nematodes were recovered from 20 of the 82 sites surveyed, with 24.4% of the slugs infected with nematodes. A total of seven nematodes were identified to species level, including Caenorhabditis elegans, Panagrolaimus papillosus, Pellioditis typica, Pelodera pseudoteres, Rhabditella axei, Rhabditoides inermiformis and Phasmarhabditis californica. An additional four specimens were identified to genus level, including Oscheius sp. (9), Pristionchus sp., Rhabditis sp. and Rhabditophanes sp. (1). The two most common nematode species were C. elegans and P. pseudoteres. The facultative parasite, P. californica, was recovered from a single Arion rufus specimen, collected from a seasonal nursery. To our knowledge, this study represents the first survey of slug-associated nematodes in Canada.

Steinernema citrae n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from South Africa

Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 569-587 ◽  
Author(s):  
Nomakholwa F. Stokwe ◽  
Antoinette P. Malan ◽  
Khuong B. Nguyen ◽  
Rinus Knoetze ◽  
Louwrens Tiedt
Keyword(s):  
South Africa ◽  
New Species ◽  
Body Length ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Morphological Characters ◽  
The Body ◽  
Infective Juvenile ◽  
Western Cape ◽  
Citrus Orchards

Abstract During a survey for entomopathogenic nematodes in citrus orchards throughout South Africa, a new species of Steinernema was isolated from a citrus orchard on Rietkloof farm, near the town of Piketberg in the Western Cape Province, South Africa. The nematode was isolated from soil using the Galleria-baiting technique. Steinernema citrae n. sp. is characterised by the following morphological characters: third-stage infective juvenile with a body length of 754 (623-849) μm, distance from head to excretory pore of 56 (49-64) μm, tail length of 71 (63-81) μm, and ratio E value of 110 (85-132). The lateral pattern for the new species is 2, 7, 8, 6, 4, 2 and is not typical for the genus. Steinernema citrae n. sp. is closely related the feltiae-group. The body length of the IJ is close to that of S. texanum and S. weiseri, though it differs in body diam., the length of the pharynx and E%. The male of S. citrae n. sp. differs from S. feltiae in the length and shape of the spicule and body diam. Steinernema citrae n. sp. differs from all species in the feltiae-group in the morphology of the vulva, as it has a single flapped, low, epiptygma. It also differs from the most closely related species, S. feltiae, as there is no interbreeding between the two species. In addition, the new nematode differs from other species of the feltiae-group by characteristics of the ITS and D2D3 regions of its rDNA.

A new entomopathogenic nematode, Steinernema colombiense n. sp. (Nematoda: Steinernematidae), from Colombia

Nematology ◽  
2008 ◽  
Vol 10 (4) ◽  
pp. 561-574 ◽  
Author(s):  
Juan Carlos López-Núñez ◽  
Kathryn Plichta ◽  
Carmenza E. Góngora-Botero ◽  
S. Patricia Stock
Keyword(s):  
Excretory Pore ◽  
Sequence Data ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Rdna Sequence ◽  
Its Rdna ◽  
Infective Juvenile ◽  
Diagnostic Features ◽  
Rdna Sequences ◽  
Rdna Sequence Data

Abstract A new entomopathogenic nematode, Steinernema colombiense n. sp., is described from Colombia. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation studies were used for diagnostics and identification purposes. In addition, 28S and ITS rDNA sequence data were used to assess evolutionary relationships of the new species with other Steinernema spp. Morphological diagnostic features for S. colombiense n. sp. include morphometric features of the third-stage infective juvenile, including body length of 636 (549-732) μm, narrow body diam. (31 (22-36) μm), position of the excretory pore (35 (31-40) μm), tail length (41 (32-53) μm), D% = 29 (25-33) and E% = 205 (138-284). In addition, males of first and second generations are characterised by the morphology of the spicules and gubernaculum, the number and arrangement of the genital papillae and the excretory pore position (at 67 (56-76) and 54 (46-63) μm, for first and second generations, respectively). In addition to these traits, 28S and ITS rDNA sequences analyses both showed this species to be a distinct and unique entity.

Lost in worm space: phylogeny and morphology as road maps to nematode diversity

Nematology ◽  
2000 ◽  
Vol 2 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Paul De Ley
Keyword(s):  
Sequence Data ◽  
Nematode Species ◽  
Molecular Sequence Data ◽  
Molecular Sequence ◽  
Scientific Investigations ◽  
Taxonomic Impediment ◽  
Morphological Studies ◽  
Nematode Diversity ◽  
Specialist Knowledge ◽  
Road Maps

AbstractThe taxonomic impediment in nematology is expanding rather than receding: in the past decade estimates of nematode species richness have increased by several orders of magnitude, while the number of active nematode taxonomists has continued to decline steadily. In order to survive as a discipline in the new century, nematode taxonomy will therefore have to i) prioritise taxa that are relevant to other scientific investigations, ii) provide identification and classification tools that are easily applicable by nonspecialists, and iii) focus on revealing patterns of relatedness rather than on compiling exhaustive catalogues of species, since the latter will never remotely reach completion. Traditional morphological studies based on light microscopy do not meet these needs because they provide insufficient character resolution and require too much specialist knowledge. Phylogenetic approaches are more promising, especially when incorporating molecular sequence data as well as other non-traditional character suites. En nématologie, les obstacles taxinomiques sont en accroissement plutôt qu’en recul: pendant la dernière décennie, les estimations relative à la diversité en espèces ont été accrues par plusieurs ordre de grandeur tandis que le nombre de taxinomistes a continué à décroître régulièrement. Pour se maintenir en tant que discipline au cours du nouveau siècle, la taxinomie nématologique devra donc i) donner priorité à des taxons en relation directe avec d’autres recherches scientifiques, ii) produire des instruments d’identification et de classification plus accessibles aux non-spécialistes, et iii) se concentrer sur la découverte de relations d’affinité plutôt que sur la compilation de catalogues d’espèces lesquels n’atteindront jamais l’exhaustivité. Les études morphologiques traditionnelles basées sur la microscopie optique ne peuvent répondre à ces besoins du fait qu’elles n’ont pas une résolution suffisante pour les caractères et qu’elles requièrent trop de connaissances spécialisées. Les approches phylogénétiques sont plus prometteuses, spécialement lorsqu’elles sont basées sur des séquences moléculaires et d’autres séries de caractères non-traditionnels.

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