Recent studies of Japanese kinorhynchs are reviewed. Kinorhynchs (Phylum Kinorhyncha) are ecdysozoan animals with a body composed of head consisted of mouth cone and eversible introvert, neck, and 11 trunk segments. To date, about 230 species have been recorded worldwide, and all of them are exclusively marine meiobenthic species. In Japanese waters, 20 species have been known so far: of these, 9 species were described as new to science or reported as new to Japanese waters within this decade, and 4 species will be described/reported soon. Studies with the molecular phylogenetic and the total evidence analyses detected the phylogenetic relationships within the phylum, and suggested the new classification system. Phylogeographic study of two Echinoderes species detected the geographic population structures of the species, and suggested several historical events had affected to the population structures and distribution patterns of the two species.
A recent taxonomic review has revealed that three species of Ammodytes (Ammodytes japonicus, Ammodytes heian, and Ammodytes hexapterus) are distributed in Japanese waters. Species identification using morphological characters is difficult due to their similar appearance. A rapid and convenient method for identifying the three species of Ammodytes from Japan was developed via a multiplex haplotype-specific (MHS)-PCR of the mitochondrial COI region. Two primers designed for A. japonicus and A. hexapterus yielded species-specific amplification products in different sizes (ca. 500 bp and 300 bp, respectively). Together with a pair of universal primers for fish, about 1,500 bp can be amplified by MHS-PCR, which allows the robust identification of the three species of Ammodytes.
The scale worm Hesperonoe hwanghaiensis Uschakov and Wu, 1959 (Annelida: Polynoidae) is recorded from eastern Japan, based on four specimens collected from Akkeshi Bay, Hokkaido, and Kashima-nada, Ibaraki Prefecture. In Akkeshi Bay, three specimens (body length of a complete specimen: 40 mm, body width without parapodia: 4.0–4.5 mm), which are the largest of all Japanese specimens including previous records, were found from mud and sand sediments at intertidal flats, where a mud shrimp Upogebia major (De Haan, 1841) was collected simultaneously. In Kashima-nada, a complete mature male specimen (body length: 23 mm, body width without parapodia: 2.7 mm) was collected by dredging at subtidal sandy bottom at a water depth of 7.6 m, where another mud shrimp Austinogebia narutensis (Sakai, 1986) was collected simultaneously. The morphological characteristics of these specimens basically agreed with those of the previous records on the specimens collected from western Japan, with a diagnostic characteristic of the presence of a row of the more conical macrotubercles (up to 28 in an elytron of the complete specimen from Akkeshi Bay, and up to 3 in that from Kashima-nada) on the posterior surface of the elytra in the larger specimen. The present result suggests that the scale worm is commensal with not only U. major but also A. narutensis in its habitats extending from intertidal flats in semi-enclosed inner bays to subtidal bottom in open coasts.
Two yellowish damselfishes (Perciformes: Pomacentridae), Chromis analis (Cuvier in Cuvier and Valenciennes, 1830) and C. xouthos Allen and Erdmann, 2005, were confirmed to be distributed in Japanese waters on the basis of collected specimens and underwater photographs. Detailed comparisons of the two species are given in this study, with assessments of standard Japanese names for the two. New standard Japanese name, “Tampopo-suzumedai”, is herein proposed for C. analis.
They believe the recovery to natural/pristine circumstances by lowering the density of Japanese deer through their capture and hunting. However, a feeling of wrongness with the concept of natural/pristine circumstances has prevailed on my mind. I examine here to repel the above concept concerning the case that Japanese deer have rapidly increased in number around some areas of Japan to have significantly negative impacts on farming crops and forest ecosystems close to rural/local countries including mountain villages, that suggests sudden switches to drastic states of the ecosystems.