Five new and five known species of the genus Tylencholaimus de Man, 1876 (Nematoda: Dorylaimida: Tylencholaimoidea) from Western Ghats of India

Five new and five known species of the genus Tylencholaimus de Man, 1876 are described from the Western Ghats of India. Tylencholaimus macroamphidius sp. nov. has a 0.61–0.85 mm long body, angular lips, large amphid, 8.0–9.0 μm long odontostyle, odontophore with asymmetrical basal knobs, pharyngeal bulb expanding gradually, female genital system mono-prodelphic, and a rounded to conoid tail. Tylencholaimus shamimi sp. nov. has a 0.57–0.71 mm long body, 6.0–7.0 μm long odontostyle, odontophore with basal thickening, pharyngeal bulb expanding gradually, female genital system amphidelphic and a convex-conoid tail. Tylencholaimus southindicus sp. nov. has a 0.44–0.55 mm long body, lip region with distinct labial disc, 4.5–5.5 μm long odontostyle, odontophore with minute basal knobs, pharyngeal expansion abrupt, female genital system mono-prodelphic, and a rounded-conoid to rounded tail. Tylencholaimus striatus sp. nov. has a 0.30–0.34 mm long body with distinctly striated cuticle, 5.0–5.5 μm long odontostyle, odontophore with minute basal knobs, pharyngeal bulb expanding abruptly, female genital system mono-prodelphic, and a conoid tail with bluntly rounded terminus. Tylencholaimus tamiliensis sp. nov. has 0.51–0.58 mm long body, 5.5–6.0 μm long odontostyle, odontophore with minute basal knobs, pharyngeal bulb expanding gradually, female genital system mono-prodelphic and tail rounded to conoid with sunken terminus. Five known species of the genus Tylencholaimus viz. T. mirabilis, T. teres, T. micronanus, T. ibericus and T. cosmos also recorded from the region and redescribed/illustrated.

A new root-knot nematode, Meloidogyne vitis sp. nov. (Nematoda: Meloidogynidae), parasitizing grape in Yunnan

An unknown root-knot nematode was found at high density on grape roots collected from Yunnan Province. Morphometric traits and measurements, isozyme phenotypes, and molecular analysis clearly differentiated this nematode from previously described root-knot nematodes. This new species is described, illustrated and named Meloidogyne vitis sp. nov. The new species can be distinguished from other Meloidogyne spp. by a unique combination of characters. Females display a prominent neck, an excretory pore is located on the ventral region between 23rd and 25th annule behind lips, an EP/ST ratio of approximately 2.5 (1.98–2.96), a perineal pattern with two large and prominent phasmids, and a labial disc fused with the medial lips to form a dumbbell-shaped structure. Males display an obvious head region, a labial disc fused with the medial lips to form a dumbbell-shaped structure, no lateral lips, a prominent slit-like opening between the labial disc and medial lips, a distinct sunken appearance of the middle of the medial lips, and four incisures in the lateral field. Second-stage juveniles are characterized by a head region with slightly wrinkled mark, a labial disc fused with the medial lips to form a dumbbell-shaped structure, a slightly sunken appearance of the middle of the medial lips, a slit-like amphidial openings between the labial disc and lateral lips, and four incisures in the lateral field. The new species has rare Mdh (N3d) and Est phenotypes (VF1). Phylogenetic analysis based on ITS1-5.8S-ITS2, D2D3 fragments of rDNA, and coxI and coxII fragments of mtDNA sequences clearly separated the new species from other root-knot nematodes, and the closest relative was Meloidogyne mali. Meloidogyne mali was collected for amplifying these sequences as mentioned above, which were compared with the corresponding sequences of new species, the result showed that all of these sequences with highly base divergence (48–210 base divergence). Moreover, sequence characterized amplified region (SCAR) primers for rapid identification of this new species were designed.

Escargot is involved in labial and antennal imaginal disc development through two different developmental pathways

In insects, imaginal discs form the adult structures. Imaginal discs are formed by two epithelial layers, the lower disc proper columnar epithelium and the upper peripodial squamous epithelium (also known as peripodial membrane). During morphogenesis and metamorphosis there is a complex crosstalk between these two epithelia that defines the final size and form of the adult organs. In this work we found that in the antennal disc, the dosage of the transcriptional factor Escargot (Esg) regulates the extension of the peripodial epithelium. A reduction in Esg expands the peripodial domain at the expense of the antennal disc proper causing a distortion of the anteroposterior compartments resulting in malformations or duplications of antennae and maxillary palps. In the labial disc, a different morphogenetic pathway controls its development, and loss of esg produces a complete loss of the proboscis through a pathway that involves dpp.Summary statementThe gene escargot regulates proboscis, maxillary palps and antennae development in Drosophila melanogaster through two different developmental pathways: one involving cell adhesion protein DE-cadherin and another through the signaling molecule decapentaplegic.

A new root-knot nematode, Meloidogyne moensi n. sp. (Nematoda: Meloidogynidae), parasitizing Robusta coffee from Western Highlands, Vietnam

SummaryA new root-knot nematode, parasitizing Robusta coffee in Dak Lak Province, Western Highlands of Vietnam, is described as Meloidogyne moensi n. sp. Morphological and molecular analyses demonstrated that this species differs clearly from other previously described root-knot nematodes. Morphologically, the new species is characterized by a swollen body of females with a small posterior protuberance that elongated from ovoid to saccate; perineal patterns with smooth striae, continuous and low dorsal arch; lateral lines marked as a faint space or linear depression at junction of the dorsal and ventral striate; distinct phasmids; perivulval region free of striae; visible and wide tail terminus surrounding by concentric circles of striae; medial lips of females in dumbbell-shaped and slightly raised above lateral lips; female stylet is normally straight with posteriorly sloping stylet knobs; lip region of second stage juvenile (J2) is not annulated; medial lips and labial disc of J2 formed dumbbell shape; lateral lips are large and triangular; tail of J2 is conoid with rounded unstriated tail tip; distinct phasmids and hyaline; dilated rectum. Meloidogyne moensi n. sp. is most similar to M. africana, M. ottersoni by prominent posterior protuberance. Results of molecular analysis of rDNA sequences including the D2–D3 expansion regions of 28S rDNA, COI, and partial COII/16S rRNA of mitochondrial DNA support for the new species status.

Description of Labrys fuzhouensis sp. n. and first record of Coslenchus rafiqi (Nematoda: Tylenchidae) from China

Summary In this study, we describe Labrys fuzhouensis sp. n. based on detailed morphology revealed by scanning electron microscopy and molecular data inferred from 18S and 28S rRNA. The new species differs from other Labrys species by a combination of several morphometric and morphological characters: vulva-anus distance 66-74 μm, tail length 172-182 μm, post-uterine sac 11-12 μm, excretory duct less sclerotised, and hexagon-shaped labial disc. The novelty of L. fuzhouensis sp. n. is also confirmed by multi-dimensional scaling analysis. The 18S and 28S rRNA-based phylogenies suggest that the new species nested in the Labrys clade as sister to L. chinensis. In addition to the new species description, Coslenchus rafiqi is reported from China for the first time, the description being supplemented by the first molecular data (18S and 28S rRNA) for this species.

Description of two new and two known species of the Genus Tylencholaimellus Cobb in M. V. Cobb, 1915 (Nematoda: Dorylaimida: Tylencholaimoidea)

Two new and two known species of the dorylaimid nematode genus Tylencholaimellus Cobb in M.V. Cobb, 1915 are described and illustrated. Tylencholaimellus arabicus sp. n. collected from Saudi Arabia is characterized by having small sized body (L= 0.66–0.83 mm); outer cuticle with distinct transverse striations; inner layer thick with fine transverse striations; lip region offset by a deep constriction, inner liplets slightly raised; odontostyle 15–17 µm, odontophore 8–10 µm, combined length 25–26 μm; female genital system mono-opisthodelphic; anterior uterine sac 0.5–1.3 times midbody diameter in length; transverse vulva and short conoid tail Tylencholaimellus masakii sp. n. collected from Japan is characterized by having small sized body (L= 0.77–0.81 mm); lip region offset by a slight constriction; labial disc present; odontostyle 11–12 µm, odontophore 6–7 µm, combined length 18–18.5 μm; female genital system mono-opisthodelphic; anterior uterine sac 1.1–1.8 midbody diameter long; transverse vulva and rounded-conoid tail. Tylencholaimellus striatus Thorne, 1939 and T. projectus Siddiqi, 1964 are redescribed based on material collected from India. A diagnostic compendium of the genus Tylencholaimellus is also provided.

Description of a new species of the genus Caveonchus Siddiqi, 1982 (Nematoda: Dorylaimida) with diagnostic compendium and key to its species

Summary Caveonchus siddiqii n. sp. is described and illustrated based on specimens collected from both India and Japan. It is characterized by having a medium sized body (L= 0.86 - 1.12 mm); labial disc present; amphideal fovea flask-shaped; lip region cap-like, offset by slight constriction; odontostyle 8 - 9 μm, odontophore 10 - 12 μm; pharynx with slender anterior part which expands abruptly into the saccate basal bulb, occupying about 16 - 21 % of total neck length; female genital system mono-opisthodelphic; anterior genital branch 70 - 100 μm or 1.9 - 2.8 times the midbody diameter long; tail short, rounded, hemispheroid, 0.5 - 0.7 anal body diameter long; spicules 30 - 38 μm long; and three spaced ventromedian supplements. Its relationship with all the known species of the genus is discussed. A diagnostic compendium and a key to identification of the species is also provided.

First record of the root knot nematode, Meloidogyne minor in New Zealand with description, sequencing information and key to known species of Meloidogyne in New Zealand

Meloidogyne minor Karssen et al. 2004 was collected from perennial ryegrass (Lolium perenne L.) growing in a sports ground in Christchurch, New Zealand. This is a new record for M. minor, the first report of this nematode occurring in New Zealand, and the second report from the southern hemisphere (after Chile). In general, the New Zealand isolate of M. minor corresponds well to the descriptions of M. minor given by Karssen et al. (2004). The New Zealand isolate is characterized by having a female with dorsally curved stylet, 13–14 μm long, with transversely ovoid knobs slightly sloping backwards from shaft; rounded perineal pattern; and male with stylet 16–19 μm long, large transversely ovoid knobs sloping slightly backwards from shaft; head region not set off, labial disc elevated, lateral lips prominent; and second stage juvenile 370–390 μm long, with hemizonid posterior but adjacent to excretory pore; tail 53–63 μm long; and a distinct hyaline tail terminus 14–18 μm long. In addition, molecular phylogeny using near full length small subunit (SSU), D2/D3 expansion segments of the large subunit (LSU), the internal transcribed spacer region (ITS1 and 2), and the intergenic spacer (IGS2) of the ribosomal rDNA supports the identification.

Morphological and molecular characterization of Laimaphelenchus deconincki (Nematoda: Aphelenchoididae) based on specimens from Iran

During a survey for nematodes associated with conifers in northern Iran, a known species of Laimaphelenchus was found in the bark samples of Taxus baccata L. trees and is described and illustrated here as L. deconincki Elmiligy & Geraert, 1972. It is characterized by lacking a distinct labial disc on the cephalic region; having six amalgamated labial sectors of equal width, separated by pairs of well-developed ribs; three lines in lateral field; the presence of a vulva flap; vagina surrounded by a cuticularised tube in which the walls vary in thickness; the post-uterine sac 25–62 μm long; tail with a single stalk-like terminus and four pedunculate tubercles; and absence of males. L. deconincki is morphologically very similar to L. cocuccii, but differs in the shape of the vaginal musculature (more angular vs round). Additional information on morphological characters and also the phylogenetic relationships of this known species using sequences of the D2/D3 region of the 28S ribosomal RNA gene is provided and added herein.

Meloidogyne luci n. sp. (Nematoda: Meloidogynidae), a root-knot nematode parasitising different crops in Brazil, Chile and Iran

A new root-knot nematode parasitising vegetables, flowers and fruits in Brazil, Iran and Chile, is described as Meloidogyne luci n. sp. The female has an oval to squarish perineal pattern with a low to moderately high dorsal arc and without shoulders, similar to M. ethiopica. The female stylet is robust and 15-16 μm long; the distance from the dorsal pharyngeal gland orifice to the stylet base (DGO) is 3-4 μm. Males have a high, rounded head cap continuous with the body contour. The labial disc is fused with the medial lips to form an elongated lip structure. The head region is not marked by incomplete annulations. Male stylet robust, 20.8-23.0 μm long with rounded knobs; the DGO is 2.5-4.5 μm. The stylet of second-stage juveniles (J2) is 12.0-13.5 μm long and the DGO to the stylet base is 2.3-3.3 μm. The J2 tail is conoid with finely rounded terminus and is 40.0-48.5 μm long. Biochemically, the esterase phenotype L3 (: 1.05, 1.10, 1.25) is unique and is the most useful character to differentiate M. luci n. sp. from all other Meloidogyne species. Reproduction is by mitotic parthenogenesis (2n = 42-46 chromosomes). In a differential host test, the population from Lavandula spica, Caxias do Sul, RS State, Brazil, reproduced on tomato cv. Rutgers, tobacco cv. NC95 and pepper cv. California Wonder. No reproduction occurred on watermelon cv. Charleston Gray, cotton cv. Deltapine 61 or peanut cv. Florunner. In Neighbour-Joining analyses of ITS and D2-D3 rRNA sequences, populations of M. luci n. sp. from Brazil, Chile and Iran clustered together and were clearly separated from other Meloidogyne spp., thus confirming that all three populations are very similar and conspecific.