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 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.

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.

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.

Heterorhabditis pakistanensen. sp. (Nematoda: Heterorhabditidae) a new entomopathogenic nematode from Pakistan

2016 ◽  
Vol 91 (2) ◽  
pp. 222-235 ◽  
Author(s):  
F. Shahina ◽  
K.A. Tabassum ◽  
J. Salma ◽  
G. Mehreen ◽  
R. Knoetze
Keyword(s):  
New Species ◽  
Excretory Pore ◽  
Phylogenetic Trees ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Its Region ◽  
12S Rrna ◽  
Rrna Gene ◽  
Spicule Length ◽  
The Right

AbstractA new entomopathogenic nematode species ofHeterorhabditis, described asH. pakistanensen. sp., was isolated from soil samples around the roots of grass at Malir, Karachi, Sindh, Pakistan. The new species is characterized morphologically by features of males: body size 819 μm (720–1013 μm), D% ((distance from anterior end to excretory pore divided by pharynx length) × 100) 119 (110–126), SW% ((spicule length divided by anal body diameter) × 100) 156 (144–191), GS% ((gubernaculum length divided by spicule length) × 100) 58 (48–65) and variations in the number of bursal papillae of the terminal group: 8th and 9th papillae sometimes absent on both sides, sometimes eight papillae present on the right side whereas six papillae present on the left side. On the right side the arrangement of papillae is 1 + 2 + 3 + 2 whereas on the left side it is 1 + 2 + 3. The hermaphrodite has a prominent post-anal swelling and a conoid tail 82 μm (64–95 μm) long with a pointed terminus. Hermaphrodites ofH. pakistanensen. sp. can be distinguished from all species ofHeterorhabditisexceptH. downesiby having a mucronate tail. Infective juveniles have a medium-sized body (581 μm (558–624 μm)), long pharynx (117 μm (113–125 μm)), ensheathed tail (99 μm (95–110 μm)) and E% ((distance from anterior end to excretory pore divided by tail length) × 100) 100 (95–107). The new species can be distinguished from all species ofHeterorhabditisby the absence of the 7th, 8th and 9th bursal papillae.Heterorhabditis pakistanenseis further characterized by the internal transcribed spacer (ITS) and the D2D3 region of the 28S rDNA gene. The closest speciesH. indica, H. gerrardi, H. amazonensisandH. noenieputensisbeing separated by 9, 7, 66 and 15 bp, respectively, in the ITS region. Molecular phylogenetic trees based on sequences of ITS rDNA, D2D3 regions and the mitochondrial 12S rRNA gene support the description ofH. pakistanenseas a new species.

Steinernema borjomiense n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Georgia

Nematology ◽  
2018 ◽  
Vol 20 (7) ◽  
pp. 653-669 ◽  
Author(s):  
Oleg Gorgadze ◽  
Elena Fanelli ◽  
Manana Lortkhipanidze ◽  
Alberto Troccoli ◽  
Medea Burjanadze ◽  
...  
Keyword(s):  
New Species ◽  
18S Rrna ◽  
Entomopathogenic Nematode ◽  
Phylogenetic Analyses ◽  
Tail Length ◽  
Morphological Characters ◽  
18S Rrna Gene ◽  
The Body ◽  
Rrna Gene ◽  
A New Species

Summary A new species of entomopathogenic nematode, Steinernema borjomiense n. sp., was isolated from the body of the host insect, Oryctes nasicornis (Coleoptera: Scarabaeidae), in Georgia, in the territory of Borjomi-Kharagauli. Morphological characters indicate that the new species is closely related to species of the feltiae-group. The infective juveniles are characterised by the following morphological characters: body length of 879 (777-989) μm, distance between the head and excretory pore = 72 (62-80) μm, pharynx length = 132 (122-142) μm, tail length = 70 (60-80) μm, ratio a = 26.3 (23.0-29.3), H% = 45 (40-51), D% = 54 (47-59), E% = 102 (95-115), and lateral fields consisting of seven ridges (eight incisures) at mid-body. Steinernema borjomiense n. sp. was molecularly characterised by sequencing three ribosomal regions (the ITS, the D2-D3 expansion domains and the 18S rRNA gene) and the mitochondrial COI gene. Phylogenetic analyses revealed that S. borjomiense n. sp. differs from all other known species of Steinernema and is a member of the monticolum-group.

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.

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.

Steinernema apuliae sp. n. (Rhabditida: Steinernematidae): a new entomopathogenic nematode from southern Italy

Zootaxa ◽  
2004 ◽  
Vol 460 (1) ◽  
pp. 1 ◽  
Author(s):  
ORESTE TRIGGIANI ◽  
ZDENEK MRÁ»EK ◽  
ALEX REID
Keyword(s):  
First Generation ◽  
Southern Italy ◽  
Entomopathogenic Nematode ◽  
Rflp Analysis ◽  
Tail Length ◽  
Its Region ◽  
The Body ◽  
Steinernema Glaseri ◽  
Pcr Rflp ◽  
H 41

Steinernema apuliae sp. n. has been found in soil samples collected along a saltpan border habitat in southern Italy characterized by a salted silt soil. This species belongs to the long-IJ nematode group represented by Steinernema glaseri (Steiner, 1929) and Steinernema arenarium (Artyukhovsky, 1967) among others. However, it differs from these taxa in some morphometric values such as V%, H%. Females possess asymmetrical, oblique slit vulva, slant vagina and small flap in the vulval opening. These characteristics are more distinct in second generation females which is different from most other steinernematids; the vulva position is behind the mid-body about 57% to 61% of the body length. First-generation females have a conical-like tip bearing 2 to 3 papilla-like protuberances. Male mucron is absent in both generations. Lightly brown spicules have bluntly pointed tip and elongated manubrium. Third-stage infective juveniles are on average over 1000 m long; the position of the excretory pore is posterior (D% 66) and the hyaline layer is less than half the tail length (H% 41 42). Lateral fields are formed by 8 equally distributed ridges. S. apuliae differs from S. glaseri and S. arenarium and is separated by PCR-RFLP analysis of the ITS region. There were no positive cross-breedings among these species.

A new entomopathogenic nematode, Steinernema xinbinense n. sp. (Nematoda: Steinernematidae), from north China

Nematology ◽  
2012 ◽  
Vol 14 (6) ◽  
pp. 723-739 ◽  
Author(s):  
Juan Ma ◽  
Juan Ma ◽  
Shulong Chen ◽  
Juan Ma ◽  
Shulong Chen ◽  
...  
Keyword(s):  
New Species ◽  
Dna Sequences ◽  
First Generation ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Tail Length ◽  
Northern China ◽  
Morphological Characters ◽  
Liaoning Province ◽  
Lateral Field

During a survey for entomopathogenic nematodes in northern China, a new species of Steinernema was isolated from soil samples collected from Xinbin county, Liaoning province. This nematode was obtained by the insect-baiting technique using last instar larvae of Galleria mellonella. It is described herein as S. xinbinense n. sp. The nematode can be separated from other described species of the group by morphological and morphometric characteristics of the different stages and by characterisation and phylogeny of DNA sequences of the D2D3 domain of the LSU or ITS regions of rDNA. This new species is characterised by the following morphological characters: infective third-stage juvenile with a body length of 694 (635-744) μm, distance from head to excretory pore of 51 (46-53) μm, tail length of 73 (61-81) μm, E = 71 (65-78)%, presence of eight unevenly spaced and developed ridges in middle lateral field (i.e., nine lines). First generation male with well curved, yellowish spicules 56 (49-62) μm long and gubernaculum 35 (30-41) μm long, small mucron mostly present, first generation female with protruding vulva, tail conical with one or two small mucrons and D = 45 (41-50)%. Cross hybridisation tests with S. tielingense, S. kraussei, S. feltiae and S. hebeiense showed that this species was reproductively isolated. The analyses of ITS-rDNA and D2D3 sequence confirm that the studied nematode isolate is a valid new species belonging to the ‘feltiae-kraussei-oregonense’ group.

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.

Sign in / Sign up

Export Citation Format

Share Document