The nematode associations of two nitidulid beetles, Epuraea ocularis and Lasiodactylus pictus, and their habitat (substrate) were examined in an experimental stand in Kyoto, Japan. Beetles were collected in October 2020 using banana traps. Molecular and morphological identification recognised two nematode species: Sheraphelenchus sucus and Chylorhabditis epuraeae. Sheraphelenchus sucus was isolated exclusively from E. ocularis, while C. epuraeae was isolated from both beetle species. Dauer juveniles (DJ) of S. sucus were isolated from the substrate, rotten banana. The typological characters of S. sucus DJ are illustrated and photo-documented, and S. heterophallus n. comb. (= Aphelenchoides heterophallus Steiner, 1934 and Parasitaphelenchus heterophallus (Steiner, 1934) Rühm, 1956), recognised during a literature survey, is proposed.
Three undescribed Ruehmaphelenchus species were isolated from dead wood of Quercus crispula collected in three different localities in Japan. One of these three species was successfully cultured using Botrytis cinerea as its food fungus and is described and figured as R. fujiensis n. sp. The new species is characterised by the following features: male tail, conical with or without a projection; female tail, conical with variously shaped terminal mucron or projection; and male spicule possessing a relatively long and triangular condylus. The new species is close to, or almost a cryptic species of R. digitulus, i.e., the typological characters and morphometric values of these two species are mostly overlapping. In a molecular phylogenetic relationship inferred from near-full-length small subunit (18S) and D2-D3 expansion segments of the large subunit (28S) of ribosomal RNA, the new species is close to R. asiaticus, R. digitulus, R. formosanus, and Ruehmaphelenchus sp. NKZ202; however, it was clearly separated from these species.
An undescribed Basilaphelenchus species was isolated from the dead and decaying wood of an unidentified broad-leaved tree in Kyoto, Japan. The species was cultured on a lawn of Botrytis cinerea after many attempts and kept as a laboratory strain. The nematode is characterised by the position of its secretory-excretory pore, which differs between males (anterior to median bulb) and females (overlapping or posterior to median bulb), the tail morphology of males (conical with very short mucron) and females (smoothly tapering conical with various shapes at terminus) and male spicule morphology, with spicules possessing a smoothly curved blade (calomus-lamina complex) and a shallow capitulum depression. In addition, the new species is differentiated from other members of the genus by the molecular sequences of its ribosomal RNA region. Phylogenetically, the new species is close to two Iranian species, B. brevicaudatus and B. gorganensis, but can be distinguished from them based upon its separated phylogenetic status. The genus contains five species that were described from Chile and Iran. Thus, the isolation of a species from this genus in Kyoto, Japan, represents the first record of the genus from East Asia. The new species is described and illustrated herein as B. pedrami n. sp.
Aphelenchoides xylocopae n. sp. is described and figured. The new species was isolated from the Japanese large carpenter bee, Xylocopa appendiculata circumvolans, and reared on a lawn of Botrytis cinerea. Specimens were collected from a 2-week-old culture on the fungus. The new species has a body length of 514-638 μm (males) and 532-674 μm (females). The cuticle is weakly annulated and there are three lines in the lateral field. The stylet is 10-11 μm long and has small basal swellings. Spicules are large (23-28 μm) and strongly arcuate. The male tail bears six (2 + 2 + 2) caudal papillae and is mucronate. The female tail is tapered to a pointed, amucronate or mucronate, terminus. The new species belongs to the Group 2 category of Aphelenchoides species. Cultured nematodes were used for sequencing the partial (ca 1 kbp) cytochrome oxidase subunit I of mitochondrial DNA and partial (ca 900 bp) small subunit ribosomal DNA for comparison with the sequences deposited at GenBank. The DNA sequences of A. xylocopae n. sp. were close to those of other Aphelenchoides and Bursaphelenchus species in the database, but the precise phylogenetic status of the new species could not be determined because of the limited sequences available for Aphelenchoides species.
Bursaphelenchus luxuriosae n. sp. is described and figured. Specimens were collected from a 2-week-old culture on Botrytis cinerea. The new species is characterised by a body length of 897 (710-1159) μm in the female and 745 (621-887) μm in the male, relatively robust body (a = 33-39 in the female and 27-30 in the male), stylet ca 14 (11-16) μm long, four lines in the lateral field, the large (27-30 μm) arcuate spicule with a terminal cucullus, seven (2 + 1 + 2 + 2) male caudal papillae, the long, well developed vulval flap and the shape of the female tail which is long, tapered, and ventrally bent when killed by heat with an irregular or roughened dorsal contour near the tip and an irregular terminus. The new species is considered to belong to the Bursaphelenchus xylophilus group of the genus Bursaphelenchus and is most closely related to B. conicaudatus and B. fraudulentus in spicule shape, vulval flap and 'a' values of males and females. It is easily distinguished from these two species by the morphology of female tail. The RFLP profile confirms the distinctness of the new species within the B. xylophilus group. The phylogenetic status of B. luxuriosae n. sp. within the B. xylophilus group is indicated by molecular phylogenetic analysis. Bursaphelenchus luxuriosae n. sp. is assumed to be close to B. conicaudatus and to have diverged from the ancestor of the B. xylophilus group early in the speciation of the group.
The phoretic relationships between the nematode Bursaphelenchus conicaudatus
and the yellow-spotted longicorn beetle, Psacothea hilaris, collected at
various districts in Japan were investigated. A high proportion of all ten
subspecies of the beetle examined were infected with the nematodes,
suggesting the universality of this phoretic association. Molecular analysis
based on the partial base sequence of cytochrome oxidase subunit I in the
mitochondrial DNA revealed that the phylogenetic relationships among ten
subspecies of the beetle was similar to that among associated nematode
isolates obtained from each beetle subspecies. Intraspecific vector
replacements were supposed to occur in the isolates of B. conicaudatus on
two islands. The phoretic association between the nematode and the beetle is
assumed to have been established before the divergence of P.hilaris into
A new aphelenchoidid entomoparasitic nematode was isolated from the body cavity of overwintering individuals of a tenebrionid beetle, Uloma marseuli, collected at Shiga, Japan. The nematode is characterised by its six equal-sized lips forming a dome shape continuous with body contour. It has a moderately thick stylet, with wide lumen, a long two-part long (conus + conophore) and elongate oval or pear-shaped metacorpus with glandular anterior part. The male spicules are separate with a well-developed condylus, triangular rostrum and smoothly and strongly curved calomus-lamina complex. A gubernaculum or apophysis is absent. There are two pairs of papilliform male genital papillae. Females lack a post-vulval uterine sac, have a seemingly vestigial rectum and anus, and conical tail. The combination of the typological characters of the species does not fit any currently accepted aphelenchoidid genus and is somewhat intermediate between the Ektaphelenchinae and Entaphelenchinae. The molecular phylogenetic analysis also suggested that the nematode is close to both Ektaphelenchoides (Ektaphelenchinae) and Peraphelenchus (Entaphelenchinae). Thus, the nematode is described and illustrated as Lenisaphelenchus ulomae n. gen., n. sp. and tentatively placed in the Ektaphelenchinae.