A low-cost technique to manufacture a container to process meiofauna for scanning electron microscopy

New data on known species of Hirschmanniella and Pratylenchus (Rhabditida, Pratylenchidae) from Iran and South Africa

Hirschmanniella anchoryzae from Iran and Pratylenchus hippeastri from South Africa were recovered during a survey of plant-parasitic nematodes belonging to the family Pratylenchidae. Both species were studied using morphological and molecular techniques. Hirschmanniella anchoryzae is identified based on the flattened head, short stylet (19–22 µm), excretory pore position (anterior to pharyngo-intestinal junction), spicule length (27–30 µm), and existence of an axial mucro at the tail end. Phylogenetic analysis using 28S rDNA showed monophyly of Hirschmanniella which Iranian H. anchoryzae placed close to H. halophila (EU620464; EU620465). This result was supported by the principal component analysis of Hirschmanniella species. SEM observation of the South African population of P. hippeastri showed the presence of two annuli in the lip region. Morphometric characters resembled those of specimens earlier reported from South Africa. Hierarchal cluster using morphometrical criteria showed that the Floridian (USA) and South African populations form a group. However, the principal component analysis showed variation within this species. The molecular study of P. hippeastri populations using 18S, ITS, 28S rDNA, and COI of mtDNA showed that all P. hippeastri cluster in one group and confirmed the identification of the species using both morphological and molecular techniques. In addition, the results indicated that South African populations group close to the USA populations. Illustrations of both species including light and scanning electron microscopy observations for P. hippeastri are provided.

Morphological and molecular characterization of Labronema montanum sp. n. (Dorylaimida, Dorylaimidae) from Spain

A new species of the genus Labronema, collected in a natural mountain habitat of the southern Iberian Peninsula, in Spain, is studied, including its morphological and morphometric characterization, SEM observations, and D2-D3 28S-rRNA sequences. Labronema montanum sp. n. is distinguishable by its 1.56 to 2.08 mm long body, with lip region being offset by constriction and 19 to 24 µm broad, odontostyle 21 to 29 µm long, neck 417 to 551 µm long, pharyngeal expansion 205 to 272 µm long, the presence of three cardiac lobes at the pharyngo-intestinal junction, a long and tripartite uterus, longitudinal vulva (V = 57-60), a short and rounded caudal region (19–35 µm, c = 56-86, c = 0.5-0.8), spicules 65 to 76 µm long, and 20 to 25 nearly contiguous ventromedian supplements with hiatus.

Morphological and molecular characterization of Lenonchium zanjanense sp. n. (Dorylaimida, Nordiidae) from Iran, with new insights into the phylogeny of the genus and a revision of its taxonomy

The new species Lenonchium zanjanense sp. n. is described from a natural habitat of Zanjan province, Iran, including line, light microscopy and scanning electron microscopy illustrations and a molecular (18S, 28S) study. It is characterized by its 3.50-4.51 mm long body, rounded lip region, continuous and 13.5-15.5 µm broad, odontostyle 21-24 µm long, neck 362-490 µm long, double guiding ring, pharyngeal expansion 190-285 µm long, female genital system didelphic-amphidelphic, uterus simple and 185-320 µm long or 3.4-5.9 times the corresponding body diameter, vulva nearly equatorial (V = 45-53), tail conical-elongated to filiform (90-165 µm, c = 23-43, c' = 2.4-5.3) with three or four mucro-like projections at the tip, spicules 58-64 µm long and 16-21 contiguous ventromedian supplements ending at the level of the anterior end of the spicules. The taxonomy of the genus is updated, with an emended diagnosis, list of species, key to their identification and a compendium of their main morphometrics. Lenonchium asterocaudatum is regarded as identical and a junior synonym of L. denticaudatum. New insights into the phylogeny of the group are also provided, and the classification of Lenonchium within Nordiidae is seriously questioned.

Description of Acrobeles aenigmaticus sp. n. (Rhabditida: Cephalobidae), an unusual species with a poorly developed vulva, from the Kalahari Desert (Ngamiland, Botswana)

Acrobeles aenigmaticus sp. n. is described from the North-West District (Ngamiland) of Botswana, which forms part of the Kalahari Desert. This new species is characterised by its body length, ‘double’ cuticle bearing numerous interannular punctations, lateral fields with two longitudinal incisures, lips triangular bearing triangular tines with variation in their morphology, labial probolae bifurcated with prongs bearing triangular tines, pharyngeal corpus 2.8-3.8 times the isthmus length, spermatheca 0.8-1.8 times the body diam., post-vulval sac 1.3-2.2 times the body diam., vagina bent to the left side, vulva located left subventral and very reduced, female tail conoid-elongate, male tail conoid, spicules 24-29 μm and gubernaculum 13-17 μm in length. Molecular characterisation of 18S and 28S rRNA shows the relationship of this species with other species of Acrobeles that also present a ‘double’ cuticle, as well as with other cephalobids (e.g., Cervidellus alutus) with the same characteristic in terms of its cuticle.

Description of Geocenamus vietnamensis sp. n. (Nematoda: Merliniidae) from Vietnam

A new species of the genus Geocenamus was isolated from soil and root samples from the rhizosphere of Casuarina equisetifolia (Casuarinaceae) in Quang Nam province, Vietnam. This species is characterized by a round-to-hexagonal labial disc, the presence of a labial region, which is continuous or slightly offset from the body with six sectors, lateral sectors of first labial annulus being smaller than the submedian sectors, the presence of six to seven labial annules; the absence of deirids; stylet length 24 to 28 μm long, body length 776 to 979 μm long; lateral field with six to eight lateral lines, without areolation at mid-body and with areolation in outer bands at the tail region and a pointed tail terminus. Geocenamus vietnamensis n. sp. most closely resembles G. boghiae in having a non-sclerotized head framework and lacking a bursa in the males. It can be clearly distinguished from all other species of the genus Geocenamus by these characteristics. The combination of morphology, morphometric features, and phylogenetic trees, based on D2–D3 of 28S and ITS rDNA sequences, showed that this new species can be clearly separated from all other sequenced species. This record is the first for Geocenamus in Vietnam.

Meloidogyne daklakensis n. sp. (Nematoda: Meloidogynidae), a new root-knot nematode associated with Robusta coffee (Coffea canephora Pierre ex A. Froehner) in the Western Highlands, Vietnam

The root-knot nematode species Meloidogyne daklakensis n. sp. was discovered on the roots of Robusta coffee (Coffea canephora Pierre ex A. Froehner) in Dak Lak Province, Vietnam. This species is characterized by the females having rounded or oval perineal patterns, smooth, regular, continuous striae, and reduced lateral lines. The dorsal arch is low, rounded and encloses a quite distinct vulva and tail tip. The stylet is normally straight with well-developed and posteriorly sloped knobs. The males have a rounded cap that extends posteriorly into the lip region. The procorpus is outlined distinctly, and is three times longer than the metacorpus. The metacorpus is ovoid, with a strong valve apparatus. The species closely resembles M. marylandi, M. naasi, M. ovalis, M. panyuensis, M. lopezi, M. mali and M. baetica in the perineal pattern of the females, and the morphology of the males and the second-stage juveniles. Nonetheless, it can be differentiated from other species by a combination of morphometric, morphological and molecular characteristics. Phylogenetic analysis was conducted based on the internal transcribed spacer (ITS) and 28S rDNA as well as the region between the cytochrome c oxidase I (COI) and cytochrome c oxidase II (COII) mitochondrial genes. Herein, this nematode is described, illustrated, and designated as a new species, Meloidogyne daklakensis sp. n., based on morphometric, morphological and molecular analyses.

Redescription of Macrolaimus canadensis Sanwal, 1960 and M. ruehmi Andrássy, 1966 (Nematoda, Rhabditida, Chambersiellidae), and new data on M. crucis Maupas, 1900

Three species belonging to the genus Macrolaimus, namely M. canadensis, M. crucis and M. ruehmi, have been obtained from areas of natural vegetation in Bosnia and Herzegovina, Corsica (France), the Czech Republic and Spain. These three species are characterized by the body length of males and females, stomatal proportion of the gymnostom and cheilostom, excretory pore position, postvulval uterine sac length, male and female tail length and morphology, and the length and morphology of the spicules and gubernacula. The occurrence of M. crucis in Spain has, as a result of this study, now also been expanded to a larger area of the southern Iberian Peninsula. Morphological and morphometrical analyses showed that M. canadensis and M. ruehmi are very similar, sharing apomorphic characters. In contrast, M. crucis has plesiomorphic characters. Description, measurements and illustrations are provided for these three species.

Morphological and Molecular Characterization of Labrys filiformis n. sp. (Rhabditida: Tylenchidae) from Iran

Labrys filiformis n. sp., the second species of the rare genus Labrys , was recovered from natural forests of Gilan province and is described based upon morphological and molecular characters. The new species is characterized by its smooth cuticle under light microscopy, lateral field with two incisures forming a single plain band, lip region continuous with body contour, dorso-ventrally flattened and forming four poorly prominent lobes, having a dorso-ventrally narrower protuberant labial plate laterally extended to the amphidial margins, oral area (oral plate) dorso-ventrally elongated and embedded in the labial plate with six small labial sensilla surrounding the slightly prominent oral aperture, amphidial apertures as longitudinally lemniscatic slits bordered by the labial plate extensions which are overlapped at the middle length of amphids, stylet delicate, 6 to 7 µm long, elongate weakly developed fusiform median bulb with weak valve, wide excretory pore with long and heavily sclerotized duct, offset spermatheca filled with small spheroid sperm cells, 106 to 127 µm long elongate-conoid tail with filiform distal region and finely rounded tip. Molecular phylogenetic analyses were performed using a near-full length fragment of the 18S rDNA and the D2-D3 expansion segments of the 28S rDNA using Bayesian inference and maximum likelihood methods. In the inferred phylogenetic tree with 18S rDNA, the new species has a close affinity with several isolates of the type species, Labrys chinensis . The reconstructed phylogenetic tree using partial 28S rDNA, revealed the new species is nested inside the putative monophyletic group of several populations of L. chinensis .

On the identity of Chiloplacus subtenuis Rashid & Heyns, 1990 and C. tenuis Rashid & Heyns, 1990 (Rhabditida: Cephalobidae), with description of C. mysteriosus sp. n

Type material of Chiloplacus subtenuis and C. tenuis was studied and Iberian material originally described as C. tenuis re-examined. The results provided relevant new information to elucidate the identity of these species with more accuracy. On studying their type material, new features and details of C. subtenuis and C. tenuis were observed concerning the nature of the lip margin, morphology of the labial probolae, the lateral field at vulval level, and the orientation of the vulva (ventral or subventral). Re-examination of Iberian material of C. tenuis revealed that it consists of specimens belonging to three taxa: C. tenuis, C. membranifer, and an unknown species described and named herein as C. mysteriosus sp. n. The morphology of lip region in representatives of Chiloplacus is analysed and discussed. Zeldia spannata is transferred to Chiloplacus as C. spannatus comb. n. and Chiloplacus juniperi is regarded as a junior synonym of Nothacrobeles nanocorpus.

Studies on the morphology of Macrolaimus arboreus Truskova & Eroshenko, 1977 (Rhabditida: Chambersiellidae) from Iran

A population of Macrolaimus arboreus was collected from the rhizosphere of pine in Iran. This population of M. arboreus is characterised by the body length, 800-1010 μm in females, lip region with six seta-like papillae directed anteriad, stoma nearly as long as wide (9-11 × 7 μm), with cheilostom slightly longer than gymnostom and cheilorhabdia and gymnorhabdia well-developed, pharyngeal corpus 1.8-2.0 times the isthmus length, with slightly swollen metacorpus, excretory pore located at isthmus level, female reproductive system monodelphic-prodelphic reflexed with short post-vulval uterine sac, female tail conical (57-67 μm, c = 13.7-15.0, c′ = 3.5-3.8), ending in an acute tip which is weakly curved dorsad, and phasmids at 54-60% of tail length. Measurements and illustrations, including SEM, are provided.

First report of Pratylenchus vulnus associated with apple in Tunisia

The root-lesion nematode of the genus Pratylenchus Filipjev (1936) has a worldwide distribution and cause severe production constraints on numerous important crops. In 2013-14, during a survey of the apple nurseries and orchards in center of Tunisia (Kairouan, Zaghouan, Monastir and Kasserine), 70 different roots and soil samples were collected. The populations of root-lesion nematode were identified on the basis of their morphological and morphometric characters, and by molecular methods. Microscopic observation of females and males demonstrated the occurrence of Pratylenchusd vulnus on apple trees. The ribosomal DNA D2-D3 expansion segments of the 28S rRNA and of the Pratylenchus populations were PCR amplified and sequenced. The sequences were compared with those of Pratylenchus species in the GenBank database with high similarity (99%). This comparison reconfirmed the morphological identifications. Phylogenetic studies placed those populations with P. vulnus. This is the first report of P. vulnus infecting apple in Tunisia.

The root-lesion nematode of the genus Pratylenchus Filipjev (1936) has a worldwide distribution and cause severe production constraints on numerous important crops. In 2013-14, during a survey of the apple nurseries and orchards in center of Tunisia (Kairouan, Zaghouan, Monastir and Kasserine), 70 different roots and soil samples were collected. The populations of root-lesion nematode were identified on the basis of their morphological and morphometric characters, and by molecular methods. Microscopic observation of females and males demonstrated the occurrence of Pratylenchusd vulnus on apple trees. The ribosomal DNA D2-D3 expansion segments of the 28S rRNA and of the Pratylenchus populations were PCR amplified and sequenced. The sequences were compared with those of Pratylenchus species in the GenBank database with high similarity (99%). This comparison reconfirmed the morphological identifications. Phylogenetic studies placed those populations with P. vulnus. This is the first report of P. vulnus infecting apple in Tunisia.

Morphological and molecular characterization of Tarantobelus arachnicida gen. n., sp. n. (Nematoda, Rhabditida, Brevibuccidae), a parasitic nematode of tarantulas

A new genus and new species, Tarantobelus arachnicida, was found in the oral opening of tarantula spiders bred in captivity in Poland. The new species is characterized by having a small body (0.77-0.95 mm long in females and 0.66-0.84 mm in males), cuticle poorly annulated by transverse incisures, lateral field inconspicuous, lips separated with small cuticular flaps topping each lip, stoma panagrolaimoid with gymnostom well developed with robust and refringent rhabdia, pharynx panagrolaimoid with isthmus slightly longer than the basal bulb, intestine with cardiac (anterior) and rectal (posterior) areas with narrower walls. Mature females with intestinal cells including needle crystal packs, excretory pore at isthmus level, female reproductive system panagrolaimoid with post-vulval sac 0.4-0.8 times the length of the corresponding body diameter and having very thick walls, vulva very prominent, female rectum 0.8-1.3 times the length of the anal body diameter, female tail conical with acute tip with phasmids at 58-62% of its length. Male tail conical with long and thin mucro, spicules ventrad bent having rounded manubrium and thick gubernaculum. Description, measurements and illustrations of the new species are provided. Molecular analyses show its relationship with Brevibucca and Cuticonema. On the other hand, Medibulla and its corresponding subfamily Medibullinae, previously in Osstellidae, are transferred to Panagrolaimidae, being Shahnematinae, the junior synonym of Medibullinae. Indocephalobus, recently proposed and located in the family Panagrolaimidae, is considered a junior synonym of Diplogastrellus (Diplogasteromorpha), and its only species, I. zebrae, is considered a junior synonym of D. gracilis. In addition, a key to identification of panagrolaimoid genera is included.

On the identity of Chiloplacus magnus Rashid & Heyns, 1990 and C. insularis Orselli & Vinciguerra, 2002 (Rhabditida: Cephalobidae), two confusable species

Two very similar species of the genus Chiloplacus, namely C. magnus and C. insularis, are re-described and compared based on type material as well as Iberian specimens. Relevant new information is obtained for their characterisation and for elucidating their identity with more accuracy. Special mention is deserved by the findings regarding: i) the morphology of the lateral field at vulval level; and ii) the location of the vulva, which is either midventral or subventral, two remarkable traits that were originally overlooked. Chiloplacus magnus is distinguished by having the left lateral field expanded at vulval level and the vulva displaced to a subventral position, whereas C. insularis displays the usual pattern of the genus. The evolutionary relationships of the Iberian C. magnus are explored by means of D2-D3 sequence analysis. Chiloplacus similis is regarded as identical to C. magnus and is proposed as a new junior synonym of the latter.

Two known species of Aporcelinus Andrássy, 2009 (Dorylaimida: Aporcelaimidae) from Vietnam, with the first molecular study of the genus

Two poorly known species of the genus Aporcelinus are characterised in detail and re-defined, including line drawings, LM and SEM pictures, on the basis of abundant material collected from natural habitats in Vietnam. Aporcelinus granuliferus is distinguished by its body 0.93-1.70 mm long, lip region offset by constriction and 15-17 μm broad, odontostyle 17-22 μm long, neck 270-403 μm long, pharyngeal expansion 132-214 μm long or 47-52% of total neck length, presence of a dorsal cell mass at the pharyngo-intestinal junction, uterus a simple tube 38-57 μm or 0.7-0.9 times than the corresponding body diam. long, V = 46-55, female tail conical (29-55 μm, c = 24-41, c′ = 0.7-1.9) with acute tip and lacking a hyaline region. Aporcelinus jiaonanensis is recognisable by its 1.11-1.71 mm long body, lip region offset by weak constriction with small inner liplets and 17-20 μm broad, odontostyle 20-23 μm long, neck 307-436 μm long, pharyngeal expansion 154-234 μm long or 47-55% of total neck length, uterus tripartite and 56-97 μm long or 1.0-1.5 times the corresponding body diam., V = 51-59, tail conical (23-43 μm, c = 29-68, c′ = 0.7-1.3) with finely rounded tip and a distinct hyaline region, spicules 51 μm long, and nine, regularly spaced, ventromedian supplements, two of them within the range of the spicules. Analysis of three D2-D3 28S rDNA gene sequences of A. jiaonanensis, the first from a representative of the genus, reveals a close relationship with members of Aporcelaimellus.

A Third New Species of Aporcelinus (Dorylaimida, Aporcelaimidae) from Vietnam, with the First SEM Study of a Representative of the Genus

A new species, the third one from Vietnam, of the genus Aporcelinus is described from natural areas. Aporcelinus falcicaudatus sp. n. is characterized by its 1.28 to 1.63 mm long body, lip region offset by weak constriction and 16 to 18 µm broad, odontostyle 18 to 21 µm at its ventral side, neck 354 to 406 µm long, uterus tripartite and 61 to 95 µm long, V = 50 to 55, tail strongly recurved dorsad and conical (23-31 µm, c = 43-58, c' = 0.7-0.9) with finely rounded tip, and male absent. Scanning electron microscope (SEM) study, the first of a representative of the genus, shows a lip region pattern significantly different from that observed in the typical aporcelaimid taxa.