Kanagawa Prefectural Museum of Natural History

The concept of the ecological niche, defined as the basic habitat requirements for a species, is central to understanding species geographic distributions and predicting their responses to environmental change. However, identifying the essential niche for large regional communities remains a challenge because niche axes can be "hidden" by the complexity of the underlying ecological processes. Here, applying advanced species distribution modelling to nationwide environmental DNA survey data, we identified hidden niche axes of the Japanese coastal fish community and investigated the response diversity to these axes. Our survey detected 1,220 coastal fish species. The hidden niche axes collectively explained most of the variation in fish biodiversity and revealed five biogeographic boundaries for the regional community. These niches of the Japanese fish community may primarily relate to several processes due to ocean currents, such as environmental filters, transport from source areas and dispersal barriers. We also found that the response diversity to niche axes was positively correlated with species richness, although local communities with particularly high response diversity were geographically biased. A better understanding of the niche axes of the regional ecological community should help to mitigate the loss of biodiversity and ecosystem services caused by ongoing environmental change.

BackgroundThe cosmopolitan genus Callitriche (Plantaginaceae) is a clade of small herbaceous plants that encompasses terrestrial and aquatic species. In Japan, six Callitriche species have been identified: four native and two naturalised species. Callitricheterrestris, a naturalised terrestrial species, was first reported in 1984 in Kanagawa Prefecture and it is thriving today.New informationWe report the presence of a new naturalised terrestrial species, Callitrichedeflexa, which has been previously misidentified as C.terrestris because of its similar morphology. Callitrichedeflexa can be distinguished from C.terrestris through genetic differences and distinct morphological traits, such as longer pedicels. Re-examination of herbarium specimens in the Kanagawa Prefectural Museum of Natural History confirmed that most of the specimens labelled as C.terrestris, including voucher specimens from the original report, were indeed C.terrestris, but a few were C.deflexa. We also noted that the plants referred to as “C.terrestris” in our previous developmental studies should be corrected to C.deflexa.

The Japanese species of the genus Leptobatopsis Ashmead, 1900 are revised. A total of eight species are recorded from Japan, including a new species, Leptobatopsis yaima sp. nov., and three species, L. annularis Kasparyan, 2007, L. koreana Lee & Kang, 2015, and L. nigricapitis Chandra & Gupta, 1977, newly recorded from Japan. A Chinese species L. annularis Sheng & Sun, 2013 is a homonym of L. annularis Kasparyan, 2007. Both species are clearly different, and we therefore propose a new replacement name for the former, L. sinica (nom. nov.). Leptobatopsis daedeokensis Lee & Kang, 2015 is newly synonymised with L. annularis Kasparyan, 2007. The taxonomic position of L. nigra immaculata Momoi, 1971 is changed from a subspecies of L. nigra Cushman, 1933 to separate species, L. immaculata. The female of L. badia Momoi, 1970 is newly described. A key to the Japanese species of this genus is proposed.

A new species, Euurobraconbhaskarai Quicke, sp. nov., from West Java, Indonesia, is described, illustrated and differentiated from other members of the genus. It is closely related to the type species of the genus, E.yokahamae Dalla Torre, 1898, which is known from China, India, Japan, Laos, South Korea and Thailand. Euurobraconyokahamae is redescribed and illustrated for comparative purposes. The two species are separable mainly on colouration, but differ markedly based on their mitochondrial gene sequences (cytochrome c oxidase I, cytochrome b and 16S rDNA). The slower-evolving nuclear 28S rDNA and elongation factor 1-alpha did not differentiate E.bhaskaraisp. nov. from E.yokahamae, but consistently split Euurobracon into two species groups.

Some arbuscular mycorrhizal (AM) fungal species known to form sporocarps (i.e., aggregations of spores) are polyphyletic in two orders, Glomerales and Diversisporales. Spore clusters (sporocarp-like structures) often formed in pot cultures or in vitro conditions are supposed to be clonal populations, while sporocarps in natural habitats with a fungal peridium are morphologically similar to those of epigeous sexual (zygosporic) sporocarps of Endogone species. Thus, in this study, we explored the genetics of sporocarpic spores of two AM fungi with a view to possibilities of clonal or sexual reproduction during sporocarps formation. To examine these possibilities, we investigated single-nucleotide polymorphisms (SNPs) in reduced genomic libraries of spores isolated from sporocarps molecularly identified as Rhizophagus irregularis and Diversispora epigaea. In addition, partial sequences of the MAT locus HD2 gene of R. irregularis were phylogenetically analyzed to determine the nuclear status of the spores. We found that most SNPs were shared among the spores isolated from each sporocarp in both species. Furthermore, all HD2 sequences from spores isolated from three R. irregularis sporocarps were identical. These results indicate that those sporocarps comprise clonal spores. Therefore, sporocarps with clonal spores may have different functions than sexual reproduction, such as massive spore production or spore dispersal via mycophagy.

Twelve Planaeschna McLachlan, 1895 species recorded in Vietnam are presented and their subgroupings based on nuclear DNA analysis are discussed. Three new species are described (Planaeschna crux sp. nov. [holotype: Pia Oac NP, Cao Bang Prov.], Planaeschna samurai sp. nov. [holotype: Khau Pha, Tu Le, Yen Bai Prov.] and Planaeschna tsuchi sp. nov. [holotype: Xuan Son NP, Phu Tho Prov.]. Planaeschna celia Wilson Reels, 2001 is recorded from Vietnam for the first time. Planaeschna guentherpetersi Sasamoto, Do Vu, 2013 is shown to be a subspecies of Planaeschna ishigakiana Asahina, 1951. The female of Planaeschna cucphuongensis Karube, 1999 is described for the first time. Additional records are provided for Planaeschna asahinai Karube, 2011, Planaeschna tamdaoensis Asahina, 1996, Planaeschna tomokunii Asahina, 1996, and Planaeschna viridis Karube, 2004. Lastly, the females of two unidentified Planaeschna spp. are illustrated. Information on the ecology of all species is provided.

Watanabe, Kyohei (2021): Taxonomic and Zoogeographic Study of the Japanese Phygadeuontinae (Hymenoptera, Ichneumonidae), with Descriptions of 17 New Species. Bulletin of the Kanagawa Prefectural Museum (Natural Science) 50: 55-136, DOI: 10.32225/bkpmnh.2021.50_55, URL: https://doi.org/10.32225/bkpmnh.2021.50_55