Anatomical and molecular characterization of some rhigonematid parasites of millipedes in Nigeria, with new insights into their phylogeny.

Parasitic nematodes of millipedes from Nigeria are molecularly characterized for the first time. During nematode surveys on live giant African millipedes from several localities in Nigeria, 4 species of rhigonematids were identified by application of integrative taxonomical approaches (morpho-anatomy and molecular markers), including Brumptaemilius sp., Gilsonema gabonensis, Obainia pachnephorus, and Rhigonema disparovis. The results of morphometric and molecular analyses of D2-D3 28S, ITS, partial 18S rRNA, and cytochrome oxidase c subunit 1 (COI) gene sequences further characterized the rhigonematid species, and clearly separated them from other related species. Phylogenetic relationships based on 28S and 18S rRNA genes suggest that genera within Ransomnematoidea (Ransomnema, Heth, Carnoya, Brumptaemilius, Cattiena, Insulanema, Gilsonema) and Rhigonematoidea (Rhigonema, Obainia, Xystrognathus, Trachyglossoides, Ichthyocephaloides) clustered rather closer than could be expected in view of their morphological differences. Phylogenetic relationships based on ITS and COI are congruent with those of other ribosomal genes; however, they are not conclusive due to the scarcity of available sequences of these genes for these genera in NCBI.

A new needle nematode, Longidorus maginicus n. sp. (Nematoda: Longidoridae) from southern Spain.

During nematode surveys in natural vegetation in Sierra Mágina, Jaén province, southern Spain, a Longidorus species closely resembling Longidorus carpetanensis was found, but application of integrative taxonomic approaches clearly demonstrated that it is a new species described herein as Longidorus maginicus n. sp. The new species is amphimictic, characterized by a moderately long body (4.2-5.2 mm); lip region anteriorly flattened, slightly separated from the rest of body by a depression, 9.0-11.0 µm wide and 3.5-6.0 µm high; amphidial fovea not lobed; relatively short odontostyle (61.0-70.5 µm); guiding ring located 23.5-27.0 µm from anterior end; vulva located at 42.0%-51.3% of body length; female tail 39.0-61.0 µm long, conoid, dorsally convex with rounded terminus (c' = 1.3-2.1), with two or three pairs of caudal pores; and males common (1:2 ratio males:females), with moderately long spicules (39.0-48.5 µm) and 1 + 6-9 ventromedian supplements and three juvenile developmental stages. According to the polytomous key, codes for the new species are (codes in parentheses are exceptions): A2-B1-C2-D2-E1-F2(3)-G2-H5(4)-I2-J1-K6. The results of molecular analysis of D2-D3 28S, internal transcribed spacer region, partial 18S rDNA, and cytochrome oxidase c subunit 1 (coxI) gene sequences further characterized the new species status, and separated it from L. carpetanensis and other related species.

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.

A New Root-knot Nematode, Meloidogyne Moensi n. Sp. (Nematoda: Meloidogynidae), Parasitizing Robusta Coffee from Western Highlands, Vietnam.

A 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.

A new stem nematode, Ditylenchus oncogenus n. sp. (Nematoda: Tylenchida), parasitizing sowthistle from Adriatic coast dunes in southern Italy.

Morphological and molecular analyses of a stem nematode causing a severe disease on infected sowthistle (Sonchus bulbosus) plants, involving the formation of gall-like structures on infected leaves and stems, have led to the description of a new species named Ditylenchus oncogenus n. sp. Morphologically, the new species is characterized by a medium to large body size (all adults more than 1 mm in length); a delicate stylet (9.0-11.0 µm long) with minute, rounded knobs; a long post-vulval uterine sac (c. 65% of the vulva-anus distance); six incisures at the lateral fields and characteristic D. destructor-pattern of spicules (with pronounced ventral tumulus and anteriorly pointed, less sclerotized, cuticle parts present within the lamina). The results of molecular analysis of rRNA gene sequences, including the D2-D3 expansion regions of 28S rRNA, internal transcribed spacer (ITS) rRNA, partial 18S rRNA gene, the protein-coding mitochondrial gene, cytochrome oxidase c subunit I (COI), and the heat-shock protein 90 (hsp90) gene, support the new species status. The results of a host-suitability test indicated that the new species does not parasitize potato (Solanum tuberosum) tubers and broad bean (Vicia faba) seedlings. Histopathological observations on naturally infected sowthistle tissues revealed that D. oncogenus n. sp. causes floral stem neoplasia and midrib leaf gall formation on the type, and to date only known, host. The galls were characterized by extensive hyperplasia, where several necrotic cells in the neoplasic area were directly damaged by feeding of the nematode, whereas a number of adjacent cells showed typical cytological changes, such as granulated cytoplasm with hypertrophied nuclei and nucleoli.

The more we search, the more we find: discovering and expanding the biodiversity in the ring nematode genus Xenocriconemella De Grisse and Loof, 1965 (Nematoda: Criconematidae).

The ring nematode genus Xenocriconemella De Grisse and Loof, 1965 comprises only one nominal species, Xenocriconemella macrodora (Taylor, 1936) De Grisse and Loof, 1965. The initial objective of the present study was to investigate the morphological-morphometric and molecular diversity of 28 X. macrodora populations in the Iberian Peninsula associated with tree forests (mainly Quercus spp.). However, a detailed integrative taxonomic analysis (morphological-morphometric and molecular data) from each population and analysis of this data using principal component analysis (PCA) for morphometric data (including these 28 populations and other 25 X. macrodora populations around the world) and molecular and phylogenetic species delimitation methods revealed that X. macrodora forms a species complex. This species complex is composed by species that are morphometricly and morphologically similar, but clearly different at the molecular level. Three new species are described applying integrative taxonomy, namely as Xenocriconemella iberica sp. nov., Xenocriconemella paraiberica sp. nov. and Xenocriconemella pradense sp. nov. However, the molecular diversity of this species in USA and Italy confirmed that additional species are likely present in this species complex, and the diversity of this group may be higher than expected. The study of X. macrodora topotypes can clarify the position of this species using molecular markers under an integrative approach.

A New Root-Knot Nematode Parasitizing Sea Rocket from Spanish Mediterranean Coastal Dunes: Meloidogyne dunensis n. sp. (Nematoda: Meloidogynidae).

High infection rates of European sea rocket feeder roots by an unknown root-knot nematode were found in a coastal dune soil at Cullera (Valencia) in central eastern Spain. Morphometry, esterase and malate dehydrogenase electrophoretic phenotypes and phylogenetic trees demonstrated that this nematode species differs clearly from other previously described root-knot nematodes. Studies of host-parasite relationships showed a typical susceptible reaction in naturally infected European sea rocket plants and in artificially inoculated tomato (cv. Roma) and chickpea (cv. UC 27) plants. The species is herein described and illustrated and named as Meloidogyne dunensis n. sp. The new root-knot nematode can be distinguished from other Meloidogyne spp. by: (i) perineal pattern rounded-oval, formed of numerous fine dorsal and ventral cuticle striae and ridges, lateral fields clearly visible; (ii) female excretory pore at the level of stylet knobs, EP/ST ratio 1.6; (iii) second-stage juveniles with hemizonid located 1 to 2 annuli anteriorly to excretory pore and long, narrow, tapering tail; and (iv) males with lateral fields composed of four incisures anteriorly and posteriorly, while six distinct incisures are observed for large part at mid-body. Phylogenetic trees derived from distance and maximum parsimony analyses based on 18S, ITS1-5.8S-ITS2 and D2-D3 of 28S rDNA showed that M. dunensis n. sp. can be differentiated from all described root-knot nematode species, and it is clearly separated from other species with resemblance in morphology, such as M. duytsi, M. maritima, M. mayaguensis and M. minor.

Characterization of the Cystoid Nematode Meloidoderita kirjanovae (Nemata: Sphaeronematidae) from Southern Italy.

A population of the cystoid nematode Meloidoderita kirjanovae was detected parasitizing water mint (Mentha aquatica) in southern Italy. The morphological identification of this species was confirmed by molecular analysis using the internal transcribed spacer 1 (ITS1) and 5.8S gene sequences of nuclear ribosomal DNA (rDNA), which clearly separated it from the closely related species Meloidoderita polygoni. A phylogenetic analysis of M. kirjanovae with species of related genera was conducted using sequences of the D2-D3 expansion segments of the 28S nuclear ribosomal RNA gene. The resulting phylogenetic tree was congruent with trees from an extended dataset for Criconematina and Tylenchida. The basal position of the genus Meloidoderita together with Sphaeronema within the Criconematina clade in this tree may indicate their close relationships. The anatomical changes induced by M. kirjanovae population from Italy in water mint were similar to those reported for a nematode population infecting roots of M. longifolia in Israel. Nematode feeding caused the formation of a stellar syncytium that disorganized the pericycle and vascular root tissues.

Spatial distribution of dorylaimid and mononchid nematodes from the southeast iberian peninsula: environmental characterization of chorotypes.

The aim of this study was to determine the incidence of 18 environmental variables in the spatial distribution of 30 chorotypes (species groups with significantly similar distribution patterns) of dorylaimid and mononchid nematodes by means of logistic regression in a natural area in the southeastern Iberian Peninsula. Six variables (elevation, color chroma, clay content, nitrogen content, CaCO, and plant community associated) were the most important environmental factors that helped explain the distribution of chorotypes. The distribution of most chorotypes was characterized by some (one to three) environmental variables; only two chorotypes were characterized by five or more variables, and four have not been characterized.

Spatial Distribution of Dorylaimid and Mononchid Nematodes from Southeast Iberian Peninsula: Chorological Relationships among Species.

The spatial distribution of 138 Dorylaimid and Mononchid species collected in a natural area from the Southeast Iberian Peninsula was studied. A chorological classification was used to examine distribution patterns shared by groups of species. Eighty species were classified into 14 collective and 16 individual chorotypes. The geographical projections of several collective chorotypes are illustrated along with their corresponding distribution maps. The importance of this analysis to nematological study is briefly discussed.