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A new species of the subterranean millipede genus Antrokoreana Verhoeff, 1938, A. asuwaensis sp. nov., from the Nanatsuoguchi Mine in central Honshu, Japan, is described based on both sexes. The new species is clearly distinguished from all congeners by the distally expanded coxal process of its anterior gonopods. Characteristics of the antennomere VII, mandibular pectinate lamellae, and flagella of anterior gonopods provide insight into the diagnostic features of Antrokoreana. Nuclear 28S ribosomal RNA as well as mitochondrial cytochrome c oxidase subunit I and 16S ribosomal RNA sequences of the new species are provided, and its phylogenetic position is preliminary estimated based on the 28S and 16S rRNA sequences. The obtained phylogenies show non-monophyly of the three genera of Nemasomatidae suggesting the possibility that Antrokoreana forms a clade that is distinct from that of the other nemasomatid genera.

The Japanese islands represent one of the world's biodiversity hotspots. Their geological history and present geography resulted in a high number of endemic species in nearly all major metazoan clades. We investigated the phylogeography of three different intertidal mite species from the Ryukyu islands and southern mainland by means of morphometry and molecular genetics. None of the species represents an endemic, nearly all show distributions ranging over at least the southern and central Ryukyus. Two species, Fortuynia shibai and F. churaumi sp. n. clearly represent sister species that are derived from a common Eastern ancestor. Molecular genetic results indicate that these species separated approx. 3 Ma before the opening of the Okinawa trough, whereas F. shibai most likely showed an ancestral distribution stretching from the central Ryukyus across the Tokara strait to Japanese mainland, whereas F. churaumi probably evolved somewhere south of the Tokara strait. Phylogenetic data further indicates that long periods of isolation resulted in heterogeneous genetic structure but subsequent low sea level stands during Pleistocene allowed recent expansion and gene flow between island populations. Comparing these patterns with those of other animals, these tiny wingless mites apparently show better dispersal abilities than partially volant terrestrial organism groups.

Ceratophysella comosa sp. nov. was collected from ascomata of Ciborinia canielliae in Japan and the morphological and molecular characteristics of the species are described here. The species has 3 + 3 cephalic spines as in Ceratophysella loricata and Ceratophysella pilosa, but a plurichaetosis intermediate between C. loricata (absent) and C. pilosa (strong). The new species can be distinguished from these two species also by the number of setae on the first thorax segment and ventral tube. Partial DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene were used as DNA barcodes to distinguish species. Interspecific genetic distances of the gene were higher than the intraspecific distances between Ceratophysella species for which sequence data are available. An identification key of Japanese Ceratophysella is provided.

Studies on color vision in invertebrates have focused primarily on insect visual pigments, with little attention given to crustacean visual pigments. None of the blue-green-, blue-, or ultraviolet (UV)-sensitive-opsins have been identified in crustaceans. In addition, the discussion of visual pigments has been limited to long-wavelength-sensitive opsins in Pancrustacea. Here, we focused on Branchiopoda (Crustacea), which is a sister group of Hexapoda including insects. In the tadpole shrimp Triops granarius, the visual pigment chromophore was retinal. Multiple opsins were isolated from each of three branchiopod species, T. granarius, Triops longicaudatus, and the fairy shrimp Branchinella kugenumaensis (five, five, and four opsins from these species, respectively). Phylogenetic analyses and the presence of a lysine residue corresponding to position 90 in bovine rhodopsin suggested that three of the branchiopod opsins comprise UV-sensitive pigments. In addition, the phylogenetic relationships between insect and branchiopod UV-sensitive opsins revealed that the divergence of blue- and UV-sensitive pigments predates the Branchiopoda and Insecta divergence. The other branchiopod opsins show distant relationships to other known insect opsins and form novel clusters. The present results strongly suggest that the ancestral arthropod of the Chelicerata-Pancrustacea lineages possessed at least four types of opsins. The ancestors of Pancrustacea and the Insecta-Branchiopoda lineages possessed at least five and six types of opsins, respectively. Our results suggest that in the evolutionary process associated with each lineage, several opsins appeared and diversified with repeated gene duplication, of which some have been lost in some taxa.