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In: Nematology
In: Nematology
Author: Natsumi Kanzaki

Abstract

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.

In: Nematology

Abstract

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.

In: Nematology

Abstract

Bursaphelenchus parvispicularis n. sp. is described and figured. The new species was isolated from the bark of a dead oak tree, Quercus mongolica var. grosseserrata, and reared on Botrytis cinerea. Specimens were collected from a 2-week-old culture on Botrytis cinerea. The new species has a body length of 894 (711-1012) μm in the female and 764 (600-870) μm in the male, a ratio of 33.4 (29.7-37.1) in the female and 35.6 (31.4-45.3) in the male, and c and c′ ratios of 16.7 (14.8-19.0) and 4.4 (3.9-5.1), respectively, in the female and 24.3 (20.0-28.4) and 2.5 (2.2-2.8), respectively, in the male. The stylet is 14-16 μm long in the female and 13-15 μm in the male; there are three lines in the lateral field; the spicules are small (13 (13-15) μm long) and broad; there are seven (2 + 1 + 2 + 2) male caudal papillae; the 'bursa' varies from roundish trapezoid to rectangular with a concave terminus, and the female tail is tapered with clearly annulated dorsal surface near the tail tip and a rounded terminus. Based upon morphology the new species belongs to the B. hofmanni-group sensu Braasch. However, the new species is distinguished from the other B. hofmanni-group species by the size and form of the spicule, female tail shape, and morphometric values. Based on the molecular phylogenetic analysis of the DNA base sequences of ribosomal DNA and mtCOI gene, the new species was close to two B. hofmanni-group species (B. paracorneolus and B. hofmanni) and to B. hylobianum. This result is in accordance with their morphological similarity.

In: Nematology

Diplogasteroides luxuriosae n. sp. is described from a species of longhorn beetle, Acalolepta luxuriosa (Cerambycidae), associated with a broad-leaved tree, Aralia elata (Araliaceae), from the Ibaraki and Kyoto Prefectures of Japan. Besides its generic (or intrageneric species group-specific) characteristics, the new species is characterised and distinguished from its close relatives by its apomorphic characteristics, i.e., broad spicule with a trapezoidal shape, gubernaculum with pointed anterior, and posterior ends with two gland-like cells dorsally overlapping the vas deferens of males and large and wide receptaculum seminis of females. The new species is molecularly similar to two recently described Diplogasteroides spp., D. andrassyi and D. asiaticus. However, D. luxuriosae n. sp. is molecularly distinguished from these two species by the 6-7 bp difference in near-full-length small subunit (18S) and 10-14 bp differences in D2-D3 expansion segments of large subunit (28S) ribosomal RNA genes.

In: Nematology

A Sheraphelenchus species was isolated from a sample of sap exuding from a scar on the bark of Quercus serrata. Besides its generic characteristics, i.e., posteriorly located vulva in the female, male spicule with conspicuous dorsal limb and male tail with spike-like projection, the new species is characterised by a short stylet with a small basal swelling. The near-full-length of 18S and D2/D3 expansion segments of ribosomal RNA genes (near-full SSU and D2/D3LSU) were determined as its molecular barcode sequences and the phylogenetic status of the species (= genus Sheraphelenchus) was estimated using the near-full SSU. The molecular phylogenetic analysis revealed that the new species is included in the genus Bursaphelenchus, and is close to B. anatolius and B. kevini. Although Sheraphelenchus is phylogenetically inferred to occur within Bursaphelenchus, the new species is described herein as S. sucus n. sp., thereby retaining the genus Sheraphelenchus until additional data about morphological similarities between these two taxa are obtained.

In: Nematology

Summary

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.

In: Nematology

Abstract

The phylogenetic relationships of Bursaphelenchus conicaudatus with B. abruptus, B. fraudulentus, B. mucronatus and B. xylophilus species were analysed based on the DNA base sequences of 18S, 5.8S, ITS1 and ITS2 of rDNA and the partial code of mitochondrial cytochrome oxidase subunit I (COI) gene. The monophyly of B. abruptus and the other species in the xylophilus group was not supported, and B. abruptus could be excluded from the xylophilus group. The other species, i.e ., B. conicaudatus, B. fraudulentus, B. mucronatus and B. xylophilus were assumed to be monophyletic. The ancestor of these four species is assumed to have originated in the eastern part of the Eurasian continent as a free-living nematode inhabiting broad-leaved trees. First, B. conicaudatus branched from the ancestor in eastern Asia. Then B. fraudulentus and B. mucronatus separated from the ancestor. B. mucronatus changed its host from broad-leaved trees to conifers and spread throughout the coniferous forest over the Eurasian continent and North America. B. xylophilus might originate from a population of B. mucronatus remaining in North America after B. mucronatus had diversified.

In: Nematology