Characterisation of some Scutellonema species (Tylenchida: Hoplolaimidae) occurring in Botswana, South Africa, Costa Rica and the USA, with description of S. clavicaudatum sp. n. and a molecular phylogeny of the genus

Nematology ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 131-173 ◽  
Author(s):  
Esther Van den Berg ◽  
Louwrens R. Tiedt ◽  
Jason D. Stanley ◽  
Renato N. Inserra ◽  
Sergei A. Subbotin

The genusScutellonemacontains more than 40 species of spiral nematodes with enlarged phasmids called scutella. In this study, we provide morphological and molecular characterisation ofS. clavicaudatumsp. n.,S. brachyurus,S. bradys,S. cavenessi,S. transvaalense,S. truncatumandScutellonemasp. A. from North and Central America, and Africa. The new species,S. clavicaudatumsp. n., was found on sugarcane in South Africa and is characterised by a lack of lip annuli as inS. africanum,S. siamenseandS. truncatum. The lip region, in both males and females, is conical and marked by six large rectangular blocks separated or fused with the submedian and lateral lip sectors, which surround a round and distinct labial disc. Females of this new species also have large vaginal glands, a functional spermatheca, the lateral field posterior to the scutellum ending in a bluntly pointed shape and a clavate tail. Morphological descriptions, measurements, light and scanning electron microscopic photos and drawings are also given forS. bradys,S. cavenessi,S. transvaalenseandS. truncatum. The study of spiral nematode samples from Florida, USA, confirmed the presence of a morphologically and genetically atypical populations ofS. bradys. The morphology of theS. bradyspopulation from Bermuda grass in pasture land from central Florida fits that of type specimens of this species, but differs in having a truncate tail terminus rather than round and also a prominent spermatheca filled with flagellate spermatozoa. Other FloridaScutellonemasamples analysed in this study belonged toS. cavenessi, a species native to West Africa. This is the first report ofS. cavenessiin Florida, where it parasitises the ornamental plantSansevieria trifasciata. Our study showed a high level of intraspecific variation forScutellonemarRNA and mtDNA genes, which can reach 5.6% for the D2-D3 of 28S rRNA, 12.9% for the ITS rRNA genes and 14.4% for theCOIgene. Phylogenetic relationships withinScutellonemaare given as inferred from the analyses of the D2-D3 of 28S rRNA, ITS rRNA and theCOImtDNA gene sequences.

Nematology ◽  
2014 ◽  
Vol 16 (3) ◽  
pp. 323-358 ◽  
Author(s):  
Esther Van den Berg ◽  
Esther Van den Berg ◽  
Louwrens R. Tiedt ◽  
Esther Van den Berg ◽  
Louwrens R. Tiedt ◽  
...  

Pin nematodes of the genus Paratylenchus are widely distributed across the world and associated with many plant species. Morphological identification of Paratylenchus species is a difficult task because it relies on many characters with a wide range of intraspecific variation. In this study we provide morphological and molecular characterisation of several pin nematodes: Paratylenchus aquaticus, P. dianthus, P. hamatus, P. nanus and P. straeleni, collected in different states of the USA and South Africa. Paratylenchus aquaticus is reported from South Africa and Hawaii and P. nanus is found from South Africa for the first time. Morphological descriptions, morphometrics, light and scanning electron microscopic photos and drawings are given for these species. Molecular characterisation of nematodes using the D2-D3 of 28S rRNA and ITS rRNA gene sequence revealed that samples morphologically identified as P. aquaticus, P. hamatus and P. nanus indeed represent species complexes containing several species. Sequences of the rRNA genes are also provided for several unidentified Paratylenchus. Phylogenetic relationships within the genus Paratylenchus are given as inferred from the analyses of the D2-D3 of 28S rRNA and ITS rRNA gene sequences. We present here the most complete phylogenetic analysis of the genus.


Nematology ◽  
2013 ◽  
Vol 15 (6) ◽  
pp. 719-745 ◽  
Author(s):  
Esther van den Berg ◽  
Esther van den Berg ◽  
Louwrens R. Tiedt ◽  
Esther van den Berg ◽  
Louwrens R. Tiedt ◽  
...  

Scutellonema spp. are widely distributed across tropical and subtropical regions of the world and are associated with numerous agricultural and horticultural crops. Identification of many Scutellonema species is not always reliable, in part because many species share very similar diagnostic characters. In this study, we provide morphological and molecular characterisation of S. brachyurus from the USA and South Africa, S. bradys from Nigeria and three unidentified species from California, USA, New Zealand and Burkina Faso. Morphological descriptions, measurements, light and scanning electron microscopic photos and drawings are given for S. brachyurus. Females of S. brachyurus from the USA (type A) and South Africa (type B) showed a significant variation in the number of sectors and blocks on the lip annuli, ranging from about 4-12 and from 8-20, respectively. Molecular analysis using the D2-D3 of 28S rRNA, ITS rRNA and the COI mtDNA gene sequences revealed two distinct genotypes within S. brachyurus samples: type A (samples from USA, Italy, Korea, Taiwan) and type B (South Africa). Multivariate analyses determined that S. brachyurus from the USA and Taiwan (type A) differed from that from South Africa (type B) mainly in body, tail and DGO lengths, and ratios b′, c′, c and V. Phylogenetic relationships within Scutellonema are given as inferred from the analyses of the D2-D3 of 28S rRNA, ITS rRNA and the COI mtDNA gene sequences. PCR-RFLP diagnostic profiles and PCR with species-specific primers are developed for the studied Scutellonema species.


2016 ◽  
Vol 91 (6) ◽  
pp. 739-751 ◽  
Author(s):  
F.B. Pereira ◽  
J.L. Luque

AbstractMolecular and morphological characterization of two species of Cucullanidae from freshwater fish in Brazil are provided, one of which represented an undescribed taxon. Cucullanus opisthoporus n. sp. was collected in Cichla melaniae from River Xingu, State of Pará, and in C. pinima from River Jamarí, State of Rondônia. Nematodes referable to Cucullanus grandistomis were collected in Oxydoras niger from River Xingu. The new species has an appendage in the tail tip, ventrally covered by small spines, which is an exclusive feature of Cucullanus tucunarensis. However, C. tucunarensis differs from C. opisthoporus n. sp. based upon the relative position of deirids and the excretory pore, which are more posterior from the oesophageal end in the new species. Observations of C. tucunarensis type specimens also revealed features that were wrongly or not reported in the original description. Type specimens of C. grandistomis were observed, although they were poorly preserved. After evaluation of newly collected specimens of C. grandistomis, features unreported in the original description were observed for the first time, including the presence of an intestinal caecum. Thus, C. grandistomis was transferred to Dichelyne. Sequences of the 18S and 28S rRNA genes revealed high genetic similarity between the specimens of C. opisthoporus n. sp. from the two different hosts as well as their genetic distance from Dichelyne grandistomis n. comb. Phylogenetic reconstructions using representatives of Cucullanidae suggested the artificiality of the current morphological system adopted to separate the genera, since most genera were not monophyletic, although the availability of genetic data is still fragmented.


Nematology ◽  
2017 ◽  
Vol 19 (9) ◽  
pp. 1065-1081 ◽  
Author(s):  
Sergei A. Subbotin ◽  
Jerry Akanwari ◽  
Chau N. Nguyen ◽  
Ignacio Cid del Prado Vera ◽  
John J. Chitambar ◽  
...  

The cystoid sedentary nematodes of the Heteroderidae include more than 30 recognised species belonging to from nine to 11 genera, depending on the opinion of the authority. In the present study, we collected nematode populations of species belonging to some of these genera, as well as other cyst-forming species from different locations in the USA, Vietnam, Germany and Russia. The populations of cystoid nematodes represent seven valid species, Atalodera carolynae, Cryphodera sinensis, Meloidodera astonei, M. floridensis, M. mexicana, M. sikhotealiniensis, Rhizonemella sequoiae, two unidentified species of Atalodera, six unidentified species of Cryphodera, and three putative new species of Rhizonemella. We also obtained samples of cyst-forming nematodes that include an unidentified species of Betulodera from California, and Heterodera guangdongensis from Vietnam. A population of Rotylenchulus sp. from Arizona, intercepted in Florida, and a population of an unidentified species of Verutus from Germany were also added to this study. All of these populations were characterised using sequences of the D2-D3 of 28S rRNA, ITS rRNA or mitochondrial COI genes. A total of 89 new sequences were obtained from these analyses. Phylogenetic relationships within the family Heteroderidae were reconstructed based on the D2-D3 of 28S rRNA, ITS rRNA and mitochondrial COI gene sequences. Results revealed that the subfamily Ataloderinae was paraphyletic. Ekphymatodera thomasoni, a non-cyst-forming species, clustered with the cyst-forming nematodes. Representatives of the subfamily Verutinae formed clades within Heteroderidae. The genus Meloidodera was non-monophyletic and distributed within two clades: i) M. sikhotealiniensis and Cryphodera spp. from Asia and Europe; and ii) M. astonei, M. floridensis and M. mexicana from North America. Based on comparative molecular analysis Meloidodera alni syn. n. is proposed as a junior synonym of M. sikhotealiniensis. Problems of taxonomy and phylogeography of cystoid nematodes are also discussed.


Nematology ◽  
2009 ◽  
Vol 11 (4) ◽  
pp. 523-540 ◽  
Author(s):  
Esther Van den Berg ◽  
Sergei A. Subbotin ◽  
Zafar A. Handoo ◽  
Louwrens R. Tiedt

Abstract A new species of the genus Hirschmanniella, H. kwazuna sp. n., is described from unidentified grass growing in undisturbed veldt from South Africa. Hirschmanniella kwazuna sp. n. is characterised by having a very irregular heat-relaxed body posture, body 1522-2049 μm long, lip region low and rounded with four or five lip annuli, stylet 18-22.5 μm long, lateral field areolated along entire body, spermatheca filled with sperm, tail with 62-81 ventral annuli narrowing to a tip bearing a ventral mucro, angular crystal-like inclusions within body cavity in most of the specimens and phasmid situated 12-24 annuli or 15-26 μm anterior to tail tip. Males, like females, have crystal-like inclusions with the tail curved strongly dorsad in most specimens. Juveniles are similar to females. Molecular sequence analysis using the D2-D3 expansion segments of 28S, partial 18S and ITS rRNA sequences distinguished H. kwazuna sp. n. from H. loofi and other species of the genus. Hirschmanniella spinicaudata is reported from South Africa for the first time and described. Phylogenetic analyses based on analysis of the D2-D3, 18S and ITS rRNA genes are given for eight, ten and five valid and unidentified Hirschmanniella species, respectively.


Nematology ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 211-223 ◽  
Author(s):  
Mehrab Esmaeili ◽  
Ramin Heydari ◽  
Pablo Castillo ◽  
Juan E. Palomares-Rius

A new species of the genusDitylenchus,D.persicusn. sp., was collected around the roots of grapevine and is described and illustrated herein based on morphological and molecular studies. The new species is characterised by a body length of 783 (635-928) μm and 689 (670-715)μm in female and male, respectively, delicate stylet 6.2 (5.0-7.0)μm long, six lines in the lateral field, median bulb of pharynx well developed, muscular with crescentic valve, basal pharyngeal bulb pyriform with 10 (8-13)μm long stem extending into intestine, post-vulval uterine sac relatively short, 16 (14-18)μm long, female and male tail elongate-conoid with finely rounded terminus, and bursa covering 65-80% of male tail length. Morphologically,D.persicusn. sp. appears closer to five known species of the genus, namely:D.arachis,D.caudatus,D.clarus,D.myceliophagusandD. nanus. The results of phylogenetic analyses based on sequences of D2-D3 expansion region of 28S rRNA, ITS and partial 18S rRNA genes confirmed the close molecular relationship betweenD.persicusn. sp. and otherDitylenchusspecies such asD. myceliophagus,D. africanus,D. arachis,D. destructorandD. halictus.


Nematology ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 265-300 ◽  
Author(s):  
Esther Van den Berg ◽  
Louwrens R. Tiedt ◽  
Renato N. Inserra ◽  
Jason D. Stanley ◽  
Nicola Vovlas ◽  
...  

The results of morphological and molecular analyses of a Florida topotype and other populations of Hemicriconemoides strictathecatus showed that this sheathoid nematode consists of two morphotypes, both with an average stylet length of more than 70 μm, but having different tail termini, bluntly pointed or rounded. These findings confirmed the morphological similarity of H. strictathecatus with H. mangiferae, which was considered a junior synonym of this species as previously proposed by Decraemer & Geraert (1992, 1996). Populations of a sheathoid nematode with a stylet length ranging from 62.5 to 72.0 μm from Taiwan, China, South Africa and Venezuela and identified in previous studies as H. strictathecatus were found to be morphologically and molecularly different from this species and are now considered as representatives of H. litchi. Another sheathoid nematode population from Florida, considered to be H. mangiferae by McSorley et al. (1980), was also found to be morphologically and molecularly congruous with H. litchi. During nematological surveys in Florida, a new sheathoid nematode was detected on date palms imported from California into Florida and is described herein as H. phoenicis sp. n. This new species is related morphologically to the H. strictathecatus morphotype with pointed tail terminus. Both have a stylet longer than 70 μm. The new species is phylogenetically related to H. strictathecatus and H. litchi. It differs morphologically from other Hemicriconemoides species by the cuticular ornamentation of the annuli, which are marked by coarse longitudinal ridges, grooves and thick margins. Morphological and molecular characterisations of H. cocophillus from Mozambique and Florida, USA are also elucidated in this study. New phylogenies of the genus Hemicriconemoides as inferred from the analyses of the ITS rRNA, D2-D3 of 28S rRNA and partial coxI gene sequences are provided.


Nematology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Jianfeng Gu ◽  
Yiwu Fang ◽  
Lele Liu ◽  
Xinxin Ma ◽  
Xiaoling Lu

Summary Bursaphelenchus paraleoni n. sp. was isolated from Loblolly pine, Pinus taeda, logs from the USA. The new species is characterised by a lateral field with three lines, 13-16 μm long stylet with small basal swellings, and the excretory pore located slightly posterior to the nerve ring. The male spicules are mitten-shaped, the lamina smoothly tapering towards the distal tip. The condylus is broadly rounded, with a small dorsally bent hook, rostrum triangular or conical with finely rounded tip, and cucullus absent. One midventral precloacal papilla, one adcloacal pair and two postcloacal pairs of genital papillae are present. The bursal flap is long and spade-like with the posterior margin truncate or irregular. Females have a small vulval flap 4-6 μm long, a post-vulval uterine sac extending for 34-49% of the vulva to anus distance, a very long tail with slight ventral curvature, mostly filiform and with a finely rounded terminus, occasionally bluntly rounded. Huge variation in the tails of males and females were observed in a culture. It is similar to species of B. eidmanni, B. leoni, and B. silvestris in the leoni-group but detailed phylogenetic analysis based on 18S, ITS and D2-D3 28S sequences confirmed it as a new species.


2004 ◽  
Vol 18 (3) ◽  
pp. 235 ◽  
Author(s):  
Gregory D. Edgecombe ◽  
Gonzalo Giribet

Species assigned to the anopsobiine centipede genera Anopsobius Silvestri, 1899, and Dichelobius Attems, 1911, are widely distributed on fragments of the Gondwanan supercontinent, including temperate and tropical Australia, New Zealand, New Caledonia, the Cape region of South Africa, and southern South America. Phylogenetic relationships between Australasian and other Gondwanan Anopsobiinae are inferred based on parsimony and maximum likelihood analyses (via direct optimisation) of sequence data for five markers: nuclear ribosomal 18S rRNA and 28S rRNA, mitochondrial ribosomal 12S rRNA and 16S RNA, and the mitochondrial protein-coding cytochrome c oxidase subunit I. New molecular data are added for Anopsobius from South Africa and New Zealand, Dichelobius from New Caledonia, and a new species from Queensland, Australia, Dichelobius etnaensis, sp. nov. The new species is based on distinctive morphological and molecular data. The molecular phylogenies indicate that antennal segmentation in the Anopsobiinae is a more reliable taxonomic character than is spiracle distribution. The former character divides the Gondwanan clade into a 17-segmented group (Dichelobius) and a 15-segmented group (Anopsobius). Confinement of the spiracles to segments 3, 10 and 12 has at least two origins in the Gondwanan clade. The area cladogram for Dichelobius (Queensland (Western Australia + New Caledonia)) suggests a relictual distribution pruned by extinction.


Zootaxa ◽  
2021 ◽  
Vol 5023 (1) ◽  
pp. 107-120
Author(s):  
ABNER S. DE FREITAS ◽  
JAMES N. ZAHNISER ◽  
DANIELA M. TAKIYA

Papagona Ball, 1935 was originally described based on two species from the USA (Arizona). Both species of Papagona (P. papoosa Ball, 1935, type species of genus, and P. succinea Ball, 1935) are redescribed herein based on type specimens, including their previously unknown internal male genitalia. A new species from Brazil (Roraima) is described herein including the male and female terminalia. A taxonomic key to all included species is provided and additional diagnostic characters for this genus are proposed.  


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