Natsumi Kanzaki

Summary: Two new parasitaphelenchids are described and illustrated based on their morphological characters and molecular phylogenetic status. Both new species are associated with beetles inhabiting the dead or dying wood of Alnus hirsuta. Bursaphelenchus xenomimetesi n. sp., belonging to the hofmanni group within the genus, was isolated from a bark weevil, Xenomimetes alni and is characterised by a secretory-excretory pore located 0.6-1.2 metacorpal lengths posterior to the metacorpus, a mitten-shaped spicule without an obvious cucullus, male genital papillae arranged as and a conical, ventrally curved female tail with a variable tip shape. The new species is morphologically and phylogenetically close to B. parapinasteri but can be distinguished from it by the shape of the condylus. Ruehmaphelenchus indocryphali n. sp. was isolated from an ambrosia beetle, Indocryphalus pubipennis and is characterised by the absence of a labial plate, blunt mucrones on both male and female tails, a male spicule with a lateral spike, separate P3 and P4 male genital papillae and a ventrally arcuate female tail forming an elongated conoid. Ruehmaphelenchus indocryphali n. sp. is morphologically close to R. formosanus but can be distinguished by the shape of the condylus and the tips of the male and female tails. The new species is phylogenetically close to R. kuroshioi but can be distinguished morphologically.

Summary: Two new Poikilolaimus species are described and illustrated. Poikilolaimus yaeyamaensis n. sp. was isolated from a dampwood termite, Neotermes sugioi and is typologically and phylogenetically close to a Taiwanese species, P. carsiops , isolated from N. koshunensis . The new species shares a highly characteristic, cross-shaped stomatal opening with P. carsiops , but can be distinguished from the latter by the arrangement of its paired genital papillae (four vs five pairs), distinct morphometric values and unique molecular profiles. Poikilolaimus alni n. sp. was isolated from a wood-boring weevil, Xenomimetes alni , collected in Sugadaira, Nagano, Japan. It is typologically and phylogenetically close to P. micoletzkyi , as these two species share a characteristically thin male spicule and a conical female tail. However, the new species can be distinguished from P. micoletzkyi by its arrangement of male genital papillae, possessing eight pairs versus six pairs in the Austrian population or nine pairs in the German population, as well as by its molecular profiles.

Summary: Based on the number of incisures in the lateral field, spicule shape, arrangement of male caudal papillae, presence or absence of vulval flap, position of excretory pore and length of postvulval uterus branch, the typological taxonomic grouping of Bursaphelenchus is revised. The currently proposed grouping system of 152 Bursaphelenchus species (including subspecies) is divided into 10 groups with four incisures in the lateral field ( xylophilus , pterocarpi , okinawaensis , africanus , tokyoensis , fungivorus , posterovulvus , kevini , cocophilus and sexdentati ), three groups with three incisures ( eggersi , hofmanni and leoni ) and three groups with two incisures ( abietinus , hylobianum and sinensis ). This system effectively integrates typological morphological classification and phylogenetic analysis based on partial rDNA sequences (SSU, ITS1/2, LSU D2/D3) which exhibits similar patterns, except for the hofmanni group, where morphological characteristics do not align with the clearly delineated subgroups inferred from molecular phylogenetic trees.

Summary: During a regular survey of entomophilic nematodes, several phoretic associates and parasites were isolated from wood- and bark-associated curculionids inhabiting dead and dying Alnus hirsuta . From these nematodes, an undescribed Basilaphelenchus species, representing the second entomophilic species of the genus, obtained from a bark weevil Xenomimetes alni is described and illustrated based on its typological characters and molecular profiles. The new species, Basilaphelenchus xenomimetesi n. sp., is characterised by the position of the secretory-excretory pore, which varies between sex and among individuals, i.e. , 0.3-1.3 and 0.9-2.0 metacorpal length posterior to the metacorpus in males and females, respectively; the tail morphology of males (conical with blunt and conical mucro) and females (forming relatively broad conus weakly ventrally curved with blunt tip or blunt mucro), and male spicules with a shallow capitulum depression; condylus forming a roundish square and slightly dorsally truncate; and the rostrum forming a narrow triangle with a blunt or finger-like tip. Typologically, the new species is similar to B. gorganensis and B. brevistylus , sharing the presence of a capitulum depression and conical female tail with or without a mucro. However, the new species is distinguished from these two species by the condylus and rostrum shape. Combined phylogenetic analysis based on near-full-length small subunit and D2-D3 expansion segments of large subunit ribosomal RNA genes suggests that the genus is separated into two subclades, and that the new species is closely related to B. persicus and B. brevistylus . Nonetheless, the new species is distinguished from these two species phylogenetically.

Summary: Tree sap flow is a chemically complex environment characterised by fermentation-derived stressors such as ethanol, low pH, high osmotic pressure and hypoxia. Bursaphelenchus tadamiensis is frequently isolated from tree sap flow, suggesting adaptation to such conditions, although its stress tolerance has not been systematically examined. In this study, we evaluated the tolerance of B. tadamiensis to four stress conditions expected to occur in sap flow environments: high ethanol concentration, low pH, high osmotic pressure and hypoxia. Survival and reproductive capacity were assessed and compared with those of B. okinawaensis and Caenorhabditis elegans . Environmental measurements of ethanol concentration, pH and sugar content in natural sap flows were also conducted. Bursaphelenchus tadamiensis showed high survival under all stress conditions tested. Notably, B. tadamiensis survived at ethanol concentrations up to 15.1% and reproduced at 12.3%, which are substantially higher than ethanol concentrations measured in natural tree sap, whereas B. okinawaensis and C. elegans showed lower tolerance. The observed ethanol tolerance appears to be species-specific and is likely related to physiological rather than structural factors. This tolerance may facilitate persistence and reproduction of B. tadamiensis in the chemically fluctuating sap flow environment.

Summary: A population of a sphaerularioid nematode resembling the free-living mycetophagous stage of three genera, Deladenus , Hexatylus and Rubzovinema , was recovered from a soil sample collected from the Shur Su (Salty Water) spring region in the city of Maragheh, East Azarbaijan province, Iran. It was typologically compared with the free-living stage of all known species under the three aforementioned genera and was assigned to the genus Deladenus as a new member. The new species was described and illustrated based upon morphological, morphometric and molecular characteristics of free-living females. It is mainly characterised by having a pharyngo-intestinal junction anterior to the nerve ring, just behind the subventral gland orifices, and a secretory-excretory pore between the pharyngo-intestinal junction and hemizonid. Deladenus maraghensis n. sp. is further characterised by a medium body length of females (741-887 μ m), having six lines in the lateral fields, short stylet (6.5-7.0 μ m), vulva at 90.4-92.0%, post-vulval uterine sac (PUS) absent, small lateral vulval flaps present and a 32-38 μ m long conical tail with a rounded tip. The morphological comparisons of the new species with relevant species are discussed. In molecular phylogenetic analyses, sequences of small subunit (SSU) and D2-D3 expansion segments of large subunit (LSU) ribosomal DNA were used and the inferred topologies are discussed.

The bamboo carpenter bee, Xylocopa (Biluna) tranquebarorum tranquebarorum, is native to continental China and Taiwan, and the species invaded Japan around 2006. The bee utilizes bamboo culm for its nesting and hibernation, thereby causing structural damage to bamboo fencing and sting injuries to humans. Serious economic and ecological impacts were not expected in the early stage of its invasion. However, its distribution is rapidly expanding in Japan, and thus, its potential impacts need to be evaluated. Since the basic biology of the bee has not been examined in detail, even in its natural range, we examined the basic biology of X. t. tranquebarorum in its invasive range by evaluating its nesting preference and hibernation in several bamboo species collections in Kyoto, Japan. The field survey revealed that the bee prefers dead bamboo internodes with approximately16–28 mm of external diameter, which is well-congruent with previous studies, and does not have strict preference concerning the bamboo species, though the bee prefers Bambusa multiplex and Phyllostachys spp. in its native range. The hibernating bees in the culm sometimes share their nests with other invertebrates, including Anterhynchium gibbifrons, Dinoderus japonicus, Crematogaster matsumurai, unidentified spiders, shield bugs, and lepidopteran larvae. Within these co-habitants, the former two possibly negatively affect nesting and hibernation of the bees.

Summary: An undescribed rhabditid species was isolated from the termite Stylotermes halumicus collected in Taiwan. The nematode was cultured using nematode growth medium seeded with Escherichia coli , and the cultured material was examined morphologically and molecularly. The nematode shares several typological characters with some Poikilolaimus spp.: namely, presence of stomatal flaps, posteriorly shifted amphid, hexagonal basal bulb, antidromously reflexed ovaries, pore-like female vulva, and lack of bursa or bursal flap. However, the species is distinguished from Poikilolaimus by its very short vs moderately-long pharyngeal sleeve, presence vs absence of deirid and post-deirid, filiform vs conical tail of both sexes, nine vs less than eight pairs of male genital papillae, and wide vs narrow lateral field. Phylogenetically, the species is located at a basal or a sister position to the clade represented by Poikilolaimus but is clearly separated from the genus by genetic distance. Therefore, the species is described herein as Protopoikilolaimus formosanus n. gen., n. sp.

Summary: Seinura morellae n. sp. is described and illustrated. The new species was isolated from stag beetle larval frass obtained from dead wood of the bayberry tree, Morella rubra , and cultured using Acrobeloides sp. as prey. Seinura morellae n. sp. is characterised by its three-lined lateral field, secretory-excretory pore located at the level of the metacorpus, long post-uterine sac and elongate conical tail with filiform tip in females, male spicule with small expansion at the posterior base of the rostrum, and male tail with seven genital papillae and spike-like projection. Although the new species cannot be distinguished typologically or morphometrically from Seinura italiensis ( i.e. , it is a cryptic species), S. morellae n. sp. is distinguished from its close relatives, Seinura caverna , S. shigaensis and S. persica , and from S. italiensis by its independent phylogenetic status inferred from near-full-length ribosomal RNA small-subunit and D2-D3 expansion segments.