This study presents the results of the research on natural history of Ostracoda (Crustacea: Arthropoda). Until now, most of the extant ostracods have been regarded as having a non-segmented body plan; however, the vestiges of trunk segments are generally found in many lineages and this character makes it possible to discuss the evolution of ostracod body plan. The distributional pattern of the pore systems on the carapace is a species-specific character in ostracods and the identity of this pattern among species through the ontogenetic process strongly suggests a phylogenetic relationship among them. The hinge structure has been traditionally regarded as an important character for higher classification. However, a new aspect of ostracod phylogeny has emerged with the introduction of the concept of heterochrony, leading to the novel discovery of an evolutionary trend in ostracods. A series of field surveys revealed that the primary adaptation of ostracods from sediment surface to interstitial environments occurred on coarse sand deposits in eulittoral zones, and then the ostracods secondarily adapted to the interstice of finer deposits in littoral zones, with a reduction in body size.
The class Monogenea (Platyhelminthes) is commonly parasitic on or in aquatic or amphibious vertebrates, mainly fishes, but rarely on aquatic invertebrates. In Japan, a total of 240 nominal species of monogeneans has so far been reported. Freshwater fishes are mainly parasitized by monopisthocotyleans. Based on the number of monogenean species collected by me from Japanese freshwater fishes, 600 to 900 species of freshwater monogeneans may be found on approximately 500 species of freshwater fishes. However, only about 80 monogenean species have been reported to date. And, in total, 15 alien monopisthocotylean species have been reported from alien freshwater fishes in Japan. Monogeneans can establish more readily together with their hosts than other groups of parasites because of their simple life cycle, and some of monogeneans, especially alien species, are known to cause negative impacts on wild and farmed fish stocks. The fauna of alien monogeneans in Japan should be urgently clarified. Only 12 species of monogeneans have been reported from six of the 90 endangered freshwater fish species. It is highly desirable to clarify the monogenean fauna of the freshwater fishes on the verge of co-extinction and to conserve biological diversity of monogenean species.
Changes in species richness of animals and plants in Japan were examined based on the compiled data on exotic, extinct ad/or endangered species of vertebrates (mammmals, reptiles, amphibians and pices), invertebrates (insects, crustaceans and molluscans) and vascular plants, respectively. The highest species richness of exotic species (EXT), as well extinct and/or endangered species (ENT), was found in vascular plants (1,581 EXT and 1,821 ENT among 7,000 native species), not in insects (466 EXT and 356 ENT among 32,000 native species). The highest species richness of ENT of animals was detected not in insects (356 spp) but in molluscans (584 spp) containing species richness one-tenth as that of insects in Japan. Taking into account that percentages of RED-listed species against species richness, as well percentages of endemic species included in ENT, were much higher for larger-sized vertebrates (mammals, amphibians, reptiles and pices), these EXT as invasive exotic species should have strongly negative effects on native communities/ecosystems. EXT < ENT for these taxa would accelerate to reshape native communities/ecosystems into novel ones.
The Yamashina Institute for Ornithology holds 3,348 specimens of the Imperial Household Museum bird specimen collection (YIO-IH). The YIO-IH cannot fully give collection data from the labels attached to the specimens. Our final goal is to restore the collection data. As the first step, we surveyed the collection history of the YIO-IH. The Imperial Household Museum bird specimen collection (IH collection) was derived from specimens that two Japanese national museums had collected during before 1872 and 1923. The IH collection was separated into the following three groups: 1) specimens collected by the predecessor of the Imperial Household Museum from 1872 to 1889: 2) specimens collected by the predecessor of the National Museum of Nature and Science, Tokyo from 1875 to 1890: 3) specimens collected by the Imperial Household Museum from 1890 to 1923. Although 93.1% of the YIO-IH had had unclear dates, the year in which each specimen was collected could be narrowed down based on the IH collection history. The IH collection was considered to be the only extant national museum collection since the Meiji and Taisyo periods. The YIO-IH, composed of 83.0% of the IH collection, was considered to be an important collection for the history of Japanese museums and ornithology.
The International Society of Protistologists (ISOP) published a new classification of eukaryotes using ‘supergroups’ in 2005, which was subsequently revised in 2012. The revised classification now reflects the knowledge of protist evolution, reintroduces some formality with group names and their authority, and provides a point of reference for protist systematics. In the present review, the ISOP's revised classification with five supergroups is compared with a hierarchical classification of the Catalogue of Life (CoL)'s database and then the significance of the following three main points are explained: (i) the Chromalveolata hypothesis was rejected and the supergroup SAR was accepted, (ii) Amorphea (including mainly Amoebozoa and Opisthokonta) was proposed, and (iii) Diaphoretickes (including mainly SAR, Archaeplastida, and a group once called “Hacrobia”) with the exception of Excavata was also proposed.