First report of Xiphinema ifacolum Luc, 1961 (Dorylaimida: Longidoridae) from Nigeria

A population of a species of dagger nematode (Xiphinema) belonging to the non-americanum group was recovered from the fields of kola nut (Cola sp.) in southern Nigeria. The morphological and morphometric data obtained from this population were consistent with the characteristics of the species Xiphinema ifacolum. In addition, molecular identification based on D2-D3 expansion segments of 28S rRNA and partial mitochondrial COI gene regions confirmed its identity. According to our knowledge, this is the first report of the species from Nigeria, and the second report from Africa, after the original description from Foulaya, Guinea.

Genetic diversity, and description of a new dagger nematode, Xiphinema afratakhtehnsis sp. nov., (Dorylaimida: Longidoridae) in natural forests of southeastern Gorgan, northern Iran

The most prevalent dagger nematode recovered from rhizospheric soil samples of forest trees in the Afrātakhteh region of Golestan province (Iran) was Xiphinema afratakhtehnsis sp. nov. and it is described and illustrated with integrative approaches using both morphological and molecular criteria. It belongs to the morphospecies group 6 of the intragenic historical grouping of Xiphinema non-americanum species. The new species is characterized by females with 3.3–4.9 mm sized body, lip region separated from the rest of body by a depression, anteriorly expanded, 16–18 μm wide, vulva located at 47.2–58.5%, odontostyle 155–173 μm and odontophore 89–107 μm long, female genital system composed of two equally developed branches, the tubular part of each having spines, short symmetrically rounded female tail to symmetrically rounded with a small mucro-like projection at the end in a few females, rare males (n = 1 out of 74 females) with 83 μm long dorylaimoid spicules and four juvenile developmental stages. The third-stage juveniles (J3) have a characteristic tail shape (short, symmetrically conical with a club-shaped long mucro) demarcating the species, and being typologically useful for its separation from closely similar species (except X. cohni, with currently no data on its juvenile stages) viz. X. adenohystherum, X. iranicum, X. mazandaranense, X. nuragicum, X. pyrenaicum, X. robbinsi, X. sphaerocephalum and X. zagrosense. Molecular phylogenetic studies using genomic (partial large subunit and internal transcribed spacer 1 ribosomal RNA genes: D2-D3 and ITS1 rDNA) and mitochondrial cytochrome c oxidase subunit I gene (COI mtDNA) revealed the new species forming a unique lineage in all reconstructed trees using Bayesian inference (BI) and maximum likelihood (ML) methods. The sequenced isolates of the new species formed a monophyletic group in the D2-D3 tree. The sequenced isolates of the new species for their COI mtDNA formed four subclades in COI mtDNA phylogeny, and four haplotypes in corresponding analysis.

Description of Lelenchus brevislitus n. sp. (Nematoda: Tylenchidae), an example of a cryptic species from Iran and its phylogenetic relationships with other species in the family

Lelenchus brevislitus n. sp. is described and illustrated based on morphological, morphometric and molecular data. The new species is characterised by having females with slender, 452-488 μm long, body lateral field vestigial as a plain simple band under scanning electron microscopy (SEM) in vulval region and absent in proximal and distal body ends, cephalic region short, ca 2 μm high, conical and truncate in anterior end in lateral view under SEM, dorso-ventrally flattened, amphidial pouches pocket-shaped and large under light microscopy (LM), their apertures short (ca 1 μm long in SEM) longitudinal sinuous slits remarkably wide near the small oral disc and significantly narrowing posteriad stylet, slender. 6.5-8.0 μm long, developed median bulb with distinct valvular plates, monodelphic-prodelphic reproductive system having a short post-vulval uterine sac (PUS), transverse vulval slit (V = 47.5-51.7) bearing small lateral membranes on each side, long filiform female tail (154-170 μm, c = 2.8-3.1, c′ = 21.5-28.3), and males unknown. The new species is considered to be a cryptic species inside the Tylenchidae. Morphological comparisons with all species of the genus are discussed. Phylogenetic studies were performed for further characterisation of the new species, and the results, using nearly full length 18S rDNA data, revealed it formed a clade with an isolate of L. leptosoma, both of which are in a sister clade with an isolate of Sakia. In a reconstructed phylogenetic tree using partial 28S rDNA sequences, the new species formed a monophyletic group, again with L. leptosoma, a sister clade to some Malenchus spp.

Molecular characterisation of, and new data on, two populations of Xiphinema ingens Luc & Dalmasso, 1964 (Nematoda: Longidoridae) from Iran

Two populations of Xiphinema ingens were recovered and characterised based on morphological, morphometric and molecular data. Interesting morphological variation was observed on the nature of differentiation in uterus of females between both populations, i.e. one population had only a pseudo-Z-organ in the shape of globular bodies, whilst the second population had a similar pseudo-Z-organ but also had crystalloids which varied in size and number and were located near the pseudo-Z-globules or sometimes at some distance from them towards the vagina. Variation was also observed in the shape of tail of juveniles within each population as well as between two recovered populations. Both populations had the same range of morphometric data and formed a fully supported clade in both Bayesian inference (BI) and maximum likelihood (ML) methods of phylogenetic analyses using partial sequences of 28S rDNA D2-D3 and ITS1 regions. The two populations of X. ingens formed a clade with another Xiphinema species native to Iran (X. castilloi) in 28S and two species, X. macroacanthum and X. bernardi, in ITS1 trees.

Description of Xiphinema castilloi sp. n. (Dorylaimida: Longidoridae) from Iran and its phylogenetic relationships

Xiphinema castilloi sp. n., a new species of morphogroup 5 sensu Loof & Luc, 1990, is described and illustrated based on morphological, morphometric and molecular data. The new species is characterised by a 4.2-5.0 mm body assuming an open C to J shape after heat fixation, lip region separated from the body by a shallow depression, a 101-126 μm odontostyle, two equally developed genital tracts with pseudo-Z-organ in uterus (8-11 globular structures) and devoid of spines, tail dorsally convex conoid with a mucro, presence of functional males, and four juvenile developmental stages. By having two equally developed genital tracts, presence of pseudo-Z-organ, and similarities in tail shape of females and juveniles, the new species comes more close to X. artemisiae, X. diversicaudatum, X. erriae, X. jomercium, X. lapidosum, X. lusitanicum and X. ripogranum. The Bayesian inference (BI) and Maximum Likelihood (ML) analyses using 707 bp partial sequences of D2-D3 segment of 28S rDNA placed the new species in a monophyletic group with X. dentatum, another member of morphospecies group 5 with 1.00 Bayesian posterior probability (BPP).