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A new species and an already known species of the genus Anchistrocheles Brady & Norman, 1889 from the Pacific coast of Japan, are described in detail using scanning electron microscopy of the carapaces and soft-part anatomy of the appendages. The new species, Anchistrocheles hayatotanakai sp. nov., is only the second to be described in the genus Anchistrocheles from Japan, and this study is also the first to describe the appendages of A. yamaguchii Yajima, 1987, previously only known as a fossil from Pleistocene strata of the Atsumi Formation in central Japan. The two species are considered to be closely related because they share many common characters in their appendages, but they are distinguishable from each other based on the male and female copulatory organs, furcal chaetotaxy, brush-shaped organs, number of lateral pore systems, and outlines of the carapaces in dorsal view. Ontogenetic changes of carapace sizes were compared between three interstitial species (Anchistrocheles hayatotanakai sp. nov., A. yamaguchii, and Neonesidea sp. I) and an epifaunal species (N. sp. S). The reduction in carapace width was found to be the primary reason for the reduction in the cross-sectional area and is probably related to the adaptation to interstitial environments. The brush-shaped organs located between the 6th pair of limbs are also shown. This study is the first to report the anatomically precise position of these organs.

This study is designed to evaluate the male copulatory organs and carapace size of the inner bay benthic ostracod Bicornucythere bisanensis. The male copulatory organs demonstrate noticeable intraspecific variation in the distal lobe, especially the length of the tip, which shows a gradual variation; whereas the thickness of the distal lobe is conservative within the species. The population from central Japan (Aburatsubo Cove) showed remarkable morphological variations, with four copulatory organ types, each type defined by a combination of four shapes of the right and left distal lobes (Shape R, r, L, and l). While the variety of carapace morphotypes have been previously reported, our findings suggest that one morphotype from western Japan (Misumi-cho) should be treated as a distinct species. Thus, we described it as Bicornucythere misumiensis sp. nov.

Ankylocythere sinuosa (Rioja, 1942), a symbiotic ostracod native to North America, was found from the Japanese mitten crab Eriocheir japonica (De Haan, 1835), a species native to Japan, collected from a pond in Shizuoka City, Shizuoka Prefecture, central Japan. Introduced North American crayfish Procambarus clarkii (Girard, 1852), which is a host of A. sinuosa in their native range, inhabits ponds sympatrically with Japanese mitten crabs, and it is thought that the ostracods transferred from the exotic crayfish to the native crabs. In recent years, along with the artificial transportation of crayfish around the world, their symbiotic ostracods also have been found on the body surfaces of exotic crayfish in Europe and Japan. However, no studies have confirmed the infestation of exotic ostracods on native crustaceans in the field. A wide range of developmental stages of A. sinuosa from juveniles to adults were found in Japanese mitten crabs, and mating individuals were also found. This strongly suggests that they can reproduce on the body surface of Japanese mitten crabs. In the future, it will be necessary to strengthen measures against alien species to prevent these exotic symbionts from infestating native ecosystems, and we also need to investigate the exact impact of this symbiont on Japanese mitten crabs.

One survey was done with SCUBA diving in Ha Long Bay and Cat Ba Island, Northern Vietnam (December 2013) and another one at Nha Trang Bay Marine Protected Area, Nha Trang city, Central Vietnam and Phu Quoc Marine Protected Area, Kien Giang Province, Southern Vietnam (November 2014). Sixteen species of the genus Loxoconcha and fourteen species of the genus Xestoleberis were found and identified. Eight species of the genus Loxoconcha were identified in group A, three species in group B, two in group C and three unidentified. Meanwhile, twelve species of the genus Xestoleberis were classified in group A and two in group B according to phylogenetic groups. From geographical distribution of the pore groups of the species in two genera Loxoconcha and Xestoleberis showed that the fauna of these genera in Vietnam is close to those of southern part of Japanese Island Arc, i.e., from Amami Island to the Philippines and Australia rather than Japanese Island Arc faunas.

Herein, two new bairdiid ostracod species in the western Pacific Coast of Japan, namely Neonesidea kamiyai sp. nov. and Bairdoppilata japonica sp. nov. are described. They are the fourth and first species described in their respective genus in Japan within the Recent Bairdiidae. The description of the two new species is based on scanning electron microscopic investigation of carapaces and on the analysis of anatomy and chaetotaxy of appendages. Scanning electron microscopy of the carapace and soft-part anatomy of appendages of the two new species provided the complete species description. An asymmetric brush-shaped organ, with the right part considerably larger than the left part, is found in both species; this characteristic is suggested to be synapomorphic for some taxa in the family Bairdiidae.

This study is a first report of an interstitial ostracod from Southeast Asia. The ostracod species, Paracobanocythere vietnamensis sp. n., was found in the marine interstitial environment of Phu Quoc Island, Vietnam. Thus far, three species of this genus have been described. The morphology of the carapace as well as the appendages of this new species are quite similar to Paracobanocythere hawaiiensis and Paracobanocythere watanabei. However, we found that they could be easily distinguished according to the morphology of the male copulatory organ. Additionally, we estimated the evolutionary distances among these three species based on nucleotide and amino acid sequences of the mitochondrial CO1 gene. Similar morphologies of carapaces and appendages, and relatively small evolutionary distances according to CO1 between Paracobanocythere vietnamensis sp. n. and Paracobanocythere watanabei suggest that these two species are very closely related.

The present study reports three new species of Ostracoda, Loxoconcha damensis sp. nov., Xestoleberis vietnamensis sp. nov. and X. munensis sp. nov., from Phu Quoc Island, southwest Vietnam and Nha Trang Bay, central Vietnam. These species inhabit the coral reefs around isolated islands and can be easily distinguished from other known species based on their morphological differences, mainly in the male copulatory organ. Loxoconcha damensis sp. nov. belongs to Loxoconcha Group A, based on the distributional pattern of their pore system below the eye tubercle. Similarly, based on a combination of morphological types of pore systems, the two new Xestoleberis species belong to Xestoleberis Group A, because these species have two types of pore systems, i.e., sieve-type and lip-type. To the best of our knowledge, this study is the first report on Xestoleberididae and the second on Loxoconchidae from the Recent of Vietnam.

Family Polycopidae is one of the more abundant and diverse taxa occurring in marine interstitial environments. Most of the interstitial polycopids are so far known from Japan and belong to the genus Parapolycope Klie, 1936. In this paper we describe another four new species from Japan. A new genus, Kliecope gen. nov. is erected to include one new species Kliecope mihoensis sp. nov. and one new combination Kliecope oligohalina (Tanaka & Tsukagoshi, 2010) comb. nov. Although the morphology of Kliecope is similar to Parapolycope , the new genus has the following diagnostic characters: absence of an inward bulge on the antennular second podomere, presence of two setae bearing a sucker on the antennular third podomere, and absence of a dorsal seta on the basis of mandibula. Another three Parapolycope , Parapolycope setouchiensis sp. nov., Parapolycope subtidalis sp. nov., and Parapolycope miurensis sp. nov. are described as well. To test the phylogenetic relationship between the new genus and Parapolycope , we performed phylogenetic analyses based on the 14 18S rDNA sequences of interstitial Polycopidae species, 12 of which were newly obtained from our material. The 18S gene proved to be suitable for phylogenetic analyses in polycopids with high intraspecific or intrageneric resolution. Here we present trees obtained with maximum likelihood, maximum parsimony, and neighbour-joining methods, and they support the divergence between Kliecope and Parapolycope with high bootstrap values.

Living cytheroid ostracod fauna from South Korea is very poorly known, and so far only 12 species have been reported in the taxonomic literature with detail description. We describe one new species, Xestoleberis hujeongensis n. sp., and report three other cytheroid ostracods: X. setouchiensisOkubo, 1979; X. sagamiensis Okubo, 1976; and Hemicytherura kajiyamaiHanai, 1957 from the east coast of Korea. The new species is most closely related to Xestoleberis hanaiiIshizaki, 1968, a widely distributed and ecologically versatile species. The two species have a very similar carapace shape and soft body parts morphology. Nevertheless, the new species has a distinctively different carapace ornament (presence of wart-like structures on the male carapace), as well as hemipenis morphology. The other three species were known so far only from Japan, and the South Korean populations differ from the Japanese ones only by carapace size, while the carapace shape and all soft body parts are very similar to their original descriptions. This is also the first record of a living representative of the genus Hemicytherura Elofson, 1941 from Korea.

Low-energy Ar ions (0.5–2 keV) were irradiated to multi-layer graphenes and the damage process, the local electronic states, and the degree of alignment of the basal plane, and the oxidation process upon ion irradiation were investigated by Raman spectroscopy, soft X-ray absorption spectroscopy (XAS) and in situ X-ray photoelectron spectroscopy (XPS). By Raman spectroscopy, we observed two stages similar to the case of irradiated graphite, which should relate to the accumulations of vacancies and turbulence of the basal plane, respectively. XAS analysis indicated that the number of sp 2 -hybridized carbon (sp 2 -C) atoms decreased after ion irradiation. Angle-resolved XAS revealed that the orientation parameter (OP) decreased with increasing ion energy and fluence, reflecting the turbulence of the basal plane under irradiation. In situ XPS shows the oxidation of the irradiated multi-layer graphenes after air exposure.

The male copulatory organ is recognized as a significant character for species taxonomy in the sexually reproducing Ostracoda. However, the genus Parapolycope has a simply shaped male copulatory organ consisting almost entirely of just the copulatory duct. In this study, two new species, Parapolycope psittacina sp. nov. and Parapolycope uncata sp. nov., are described, and the characters that have taxonomic value were examined based on a morphological comparison of these new species. Carapace size, shape and surface ornamentation, and the male upper lip are valuable characteristics for species identification. The morphology of the male upper lip, especially, exhibited a remarkable sexual dimorphism, which might have a function associated with reproductive isolation. http://www.zoobank.org/urn:lsid:zoobank.org:pub:D2F2F902-C496-4861-8872-813BC310AD9F

Nearly half of the genera of the family Caligidae possess an evolutionarily novel structure called the "lunule" on the ventral surface of the frontal plate. Lunules are paired cup-like suckers that assist in securing attachment of the copepod parasite to its host. Although present in genera such as Caligus and Pseudocaligus, lunules are absent in other caligid genera such as Lepeophtheirus as well as in more primitive caligiforms such as members of the families Trebiidae and Dissonidae. We compared the morphology and development of the anterior margin of the frontal plates between two caligids, Pseudocaligus fugu and Lepeophtheirus sekii, and a more basal caligiform, Dissonus heronensis (a dissonid), using scanning electron, transmission electron, and laser confocal microscopes. Our observations suggest that the lunules originated as a modification of the marginal membranes of the ancestral frontal plates. We also demonstrated the presence of an anlagen cell population for the lunule and marginal membrane in the developing frontal plate. These primordial cells can be detected as early as the first stage of the chalimus phase. Based on these observations, an evolutionary scenario for the lunule is proposed based on cytological evidence. This case study enhances our understanding of "evolutionary novelty," which is a main focus of contemporary evolutionary developmental biology.

Two new species of the interstitial ostracod genus Parvocythere, P. gottwaldi sp. n. and P. gracilis sp. n., are herein described. Although these two new species are clearly distinguishable by certain morphological differences in elements of the male copulatory organ, and the carapace, they share the following simplified characters of the appendages and male copulatory organ: antennular fourth podomere with no suture; reduced claws on the distal end of antenna; and asymmetric male copulatory organ. The morphological differences among known and new Parvocythere species suggest that the species of this genus can be classified into two groups by the presence/absence of the suture on the antennular fourth podomere. The “Group S” is characterised by the presence of the antennular suture, and all species of this group have a two-clawed antenna and symmetric male copulatory organ, characters which are generally seen in cytheroid ostracods. The species belonging to “Group N” are characterised by the absence of the suture, regarded as a pedomorphic character, show the following characters: two clawed or one clawed antenna, and symmetric or asymmetric male copulatory organ. The morphological variation within Group N includes reductive characters regarded as an adaptation to the narrow spaces of the interstitial environment of a sandy beach. These intrageneric morphological variations of the exclusively interstitial genus Parvocythere suggest the possibilities that Group N might be derived from Group S, and that some adaptive characters to an interstitial environment could have developed after the colonisation of these environments.

SUMMARY The emergence of novel structures in the course of evolution faces an explanatory problem, leaving the gap from the ancestral structures difficult to bridge. This difficulty is caused by the lack of intermediate stages. Branchiurans are ectoparasitic crustaceans which use a pair of “suction discs” to attach to their host. These structures are modified first maxillae. During ontogeny, the first maxillae transform from a normal cephalic appendage to the specialized suction disc. However, supposedly ancestral branchiurans lack the suction discs in the adults and the first maxilla remains a normal appendage throughout. We describe the muscular arrangements in the developing first maxillae in Argulus coregoni. The suction discs originate as a fusion of the first and second podomeres. The sucker muscles of the suction discs are homologous to the muscles that insert in the second podomere at the early larval stages. The developmental process of the suction disc can be seen as a “recapitulation” of the evolutionary process. We thus show how the first maxilla can maintain not just the biological role but also a functional continuity during the evolution of the novel structure. From this example it is obvious that the intermediate stages of the emerging novelty, if present in the ontogeny, can help solve at least some of the enigmatic appearances of novel structures.

Eye degeneration is a general evolutionary tendency shown in many animal groups that are adapted to dark environments. Thus far, the degenerative process has only been discussed within a few taxonomic units, in terms of both evolution and development, and more studies are needed to deal adequately with this area of ostracod biology. The ostracods and copepods examined in the present study are small crustaceans that are widely diversified in the aquatic environment, and also in interstitial environments, and their ‘nauplius eyes’ (primitive eye in Crustacea; typically composed of three or four ocelli) show various degrees of degeneration. The ultrastructure and ontogeny of their degenerated nauplius eyes are described for the first time in the present study, using transmission electron microscopy. According to our observations, two morphotypes for degenerative nauplius eyes (i.e. ‘tapetal-less form’ and ‘pigment reduced form’) are found in both taxa. The first description of the embryogenesis of normal (none-degenerated) nauplius eyes of surface species is also provided. From a comparison between the embryogenesis of normal nauplius eyes and the postembryogenic development of the ‘tapetal-less form’, it is strongly suggested that the ‘tapetal-less form’ is derived by paedomorphic evolution. On the basis of our observations, as well as on previous studies, we propose the hypothesis that modularity, in the form of hierarchical interactions, exists in the nauplius eye (i.e. the tapetal cells constitute an independent developmental module to be distinguished from other developmental or functional modules, including both the pigmented cells and the sensory cells). According to our hypothesis on the nauplius eyes, we also discuss the possibility that the degenerative process is constrained within the general developmental and functional context. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 521–529.

Recently, there have been a few reports on the decrease in the incidence of severe Henoch-Schönlein purpura nephritis (HSPN) in Japan. To evaluate the incidence and the severity of HSPN, we examined the epidemiology and clinical manifestations of HSPN in Fukushima Prefecture over a 22-year period.We enrolled 61 patients (Group 1) diagnosed with HSPN between 1987 and 1997 and a further 59 patients (Group 2) diagnosed with HSPN between 1998 and 2008. Epidemiology, clinical features, laboratory data, pathological findings, treatment and outcome were retrospectively compared between the two groups.The mean number of patients per 100,000 children per year was 3.5 ± 1.2 in Group 1 and 3.6 ± 0.8 in Group 2. The clinical manifestations and laboratory findings at onset were comparable between Groups 1 and 2. Pathological findings in Group 1 and Group 2 were classified as ISKDC grade IIIa in 16 (26%) and 14 cases (24%), grade IIIb in 26 (43%) and 27 cases (46%), grade IV in 5 (8%) and 6 cases (10%)), grade V in 1 (2%) and 5 cases (8%), and grade VI in 2 (3%) and 2 cases (3%), respectively. There were no inter-group differences in ISKDC classification or rate of crescentic formation.Our findings suggest that the incidence of HSPN and the severity of HSPN in patients between 1987 and 1997 were similar to those in patients between 1998 and 2008 and that the number of patients with severe HSPN has not decreased.

The morphology and developmental processes of the two types of ostracod chemoreceptors, the Aesthetasc "Y" and the "Grouped setae," were compared. Cypridoidea and Pontocypridoidea, belonging to Cypridocopina, have a large baseball bat-like seta as an autapomorphic character on the second antenna, whereas most ostracod taxa with plesiomorphic characters bear "Grouped setae" consisting of multiple setae on the second antenna. Their budding positions, morphology, and ontogenetic changes were compared, and our deduction is that the Aesthetasc "Y" originated from "Grouped setae-like" organ in the Paleozoic. The morphogenetic processes in the molting period of these chemoreceptors were compared at the cellular level. The observations suggest that the "Grouped setae" are formed by hypodermal cells and share sheath cells corresponding to those of the Aesthetasc "Y" as a common constraint in the molting process of setae. We conclude that modification of the morphogenetic processes in the molting period of the "Grouped setae" gave rise to the Aesthetasc "Y" as a novel organ in the evolutionary pathway of the Ostracoda.

Two new and one known species belonging to the genus Callistocythere of the family Leptocytheridae from interstitial environments of the Okinawa Islands are fully described. Callistocythere intermedia sp. nov. is regarded as belonging to the C. japonica group, and Callistocythere ryukyuensis sp. nov. belongs to the C. minor group (these groups were established by Hanai 1957 based on carapace morphology). The redescribed Callistocythere ventricostata RuanHao, 1988 clearly differs from known leptocytherid species in the morphologies of the carapace and the male copulatory organ. The habitats of C. intermedia sp. nov. and C. ryukyuensis sp. nov. are found along the shoreline zone and the mid to high tide levels of the littoral zone, respectively, and C. ventricostata is found from the shoreline to the sub-tidal zone. These species are the first global records of interstitial leptocytherids.

A median nauplius eye is reported for the first time in a platycopid ostracod, a group hitherto considered to be blind. A new species of the platycopid ostracod genus Keijcyoidea is described from coastal rocky marine habitats on the Pacific coast of Japan. Observations of living specimens in the laboratory show that it is capable of burrowing to a depth of several millimeters in sandy sediment, using the first two head appendages (antennulae and antennae) and the furca. Females brooded a maximum of five eggs in the posterior brood space of the carapace. The homologies and phylogenetic implications of the trunk segmentation and limbs are discussed, paying particular attention to the sexually dimorphic fifth and sixth limbs; the copulatory appendages of both sexes are interpreted as being attached to trunk segments T6–T7 (counting from the posterior; T1 = posteriormost segment).

The morphology of non-genitalic structures in males is often associated with mating and courtship, and the evolution of those structures may cause speciation. In the present study, we describe a new species of marine interstitial ostracod from Japan. Morphological comparisons and molecular phylogenetic analysis based on ITS (internal transcribed spacer) 1 and ITS2 sequences revealed intraspecific variation on the male upper lip in the new species. The male upper lip of Parapolycope Klie, 1936 species has been reported to be related to mating behavior, and it likely produces species-specific stimuli for the female. The results of this study suggest that the male upper lip morphology in Parapolycope changed at the early stage of the speciation process.

Details of ostracode carapace structures were examined by SEM and TEM. The podocopine ostracode Semicytherura kazahana has major ridges on the carapace surface and develops its prismatic layer inside the adult carapace. Electron microscopy at the final molt reveals that the major ridges arise from the highly dense formation of pits within the underlying swollen epidermis, and that disappearance of the epidermis in the presumptive area of the prismatic layer occurs after the calcification of the outer lamella cuticle, and just before synthesis of the membranous layer. These facts suggest that the formation of the carapace in Semicytherura takes place via a more complex process than that of the other podocopid ostracodes.

The pore-systems of 17 extant species of Loxoconcha around Japan were studied in order to understand their phylogeny and evolution. The phylogeny was estimated by two steps. First, the 17 species were divided into two groups, Group A (12 species) and Group B (five species) by Pore pattern Below Eye tubercle (PBE) analysis. Then, intragroup relationships were estimated by Differentiation of Distributional pattern of Pore-system (DDP) analysis. PBE analysis reveals that species of Groups A and B have on average different ecological preferences. Species of Group A, which appeared in the late Pliocene, are more diverse, have both phytal and bottom-dwelling modes of life, possess fewer pore-systems in the ventral area, and inhabit normal marine environments. Species of Group B, whose oldest fossil record is the lower Miocene, are less diverse, have only bottom-dwelling species, possess more pore-systems in the ventral area, and tend to inhabit brackish water environments. The results of this study suggest that the differences in ecology may have had an impact on the late Cenozoic diversification around Japan. The primary invasion of Group B occurred before the lower Miocene,with no subsequent diversification. Group A invaded after the late Pliocene and immediately diversified, which created the present abundance of Loxoconcha species around Japan in both species diversity and variety of modes of life.

After more than two centuries of research, more than 65,000 living and fossil ostracod species have been described and studied, yet much remains to be learned about this ancient, widespread and diverse group of bivalved arthropods. Their higher classification and phylogeny are subjects of vigorous debate, as is their position in the broader picture of crustacean phylogeny. At the same time, major advances in our understanding of ostracod lineages and their relationships are resulting from the application of innovative approaches and techniques. This preface provides a contextual overview of the 15 contributions to this volume, which resulted from the 14th International Symposium on Ostracoda (ISO2001) held in 2001at Shizuoka, Japan. As such it provides a cross-section of topics at the forefront of research on the evolution and diversity of Ostracoda, and indicates directions for future work.

The genus Semicytherura belongs to the family Cytheruridae, and was distinguished from Cytherura on the basis of carapace features. Species of Semicytherura from Japan and adjacent seas can be divided into two groups. One is represented by Semicytherura miurensis Hanai, 1957, characterized by a thin, oval carapace covered with fine reticulation. The other is represented by Semicytherura henryhowei Hanai & Ikeya, 1977, characterized by a thick sub-rectangular carapace in lateral view. Semicytherura henryhowei, which is distributed from Hokkaido to Okinawa in Japan, has been regarded as having several morphotypes distinguishable on outline and reticulation of carapace. However, as a result of detailed observations on the copulatory organ, carapace outline and distributional pattern of pore systems, remarkable differences are shown to exist between the two most frequently occurring morphotypes. In order to recognize S. henryhowei sensu stricto, the carapace of the holotype was re-examined. Consequently, neither of the two morphotypes are considered to belong to S. henryhowei due to differences of carapace outline and distribution of pore systems. The two morphotypes are here regarded as independent taxa, described as new: S. kazahanan. sp. and S. sasameyukin. sp. The geographical distributions of the two new species overlap, but their micro-habitats differ from each other; the former lives on calcareous algae on rocky shores, the latter lives on silty sand bottom within the inner bay. A third new species, S. slipperi sp. nov., is also described. In view of their present geographical distributions and fossil records, the origin of this group of species would appear to be the Japanese islands or adjacent areas in and after the Miocene. This group then migrated to the Arctic Ocean and East Pacific Ocean during or before the middle Pliocene.

A data set of the number of setae on the maxillular branchial plate of podocopan ostracods was compiled from published drawings and our own dissections. A total of 168 species in six superfamilies were covered, with the Cytheroidea, Cypridoidea and Bairdioidea being best represented. The number of setae is shown to be independent of the size of the ostracod and the environment in which the species lives, but to have phylogenetic significance at superfamily level. Ontogenetic data suggest that the low number of branchial plate setae in many cytheroidean families is a paedomorphic phenomenon.

The ontogeny of the musculature and segments of the antennule of Heterocypris incongruens (Ramdohr, 1808) is documented. The musculature of the antennule of the juveniles indicates that during ontogeny the additional segments originate by existing segments dividing. Previously presented hypotheses are tested with these new data. Smith & Martens' (2000) hypothesis on the development of the antennule of Eucypris virens (Jurine, 1820) is supported and is expanded to cover other groups. There are five segments in the early juveniles of most species and some of these divide to form new segments during ontogeny. Additionally, some segments fuse together, and some segments divide and then fuse together again. Most divisions of segments produce two true segments, rather than annulations or secondary joints, but one species shows evidence of an annulation in the antennule.

Three new species of Ostracoda, Loxoconcha noharai sp. nov., L. santosi sp. nov. and L. sesokoensis sp. nov., are described from the Okinawa Islands, southern Japan. The two species Loxoconcha noharai sp. nov. and L. santosi sp. nov. live in estuaries, whereas the species L. sesokoensis sp. nov. lives in coral reefs. These species can be easily distinguished from other previously described Loxoconcha species by their morphological differences, mainly in the male copulatory organ, and distribution pattern of their pore systems. In addition, L. sesokoensis sp. nov. is suggested to be phylogenetically apart from any other Loxoconcha species which have been reported so far from Japan and the adjacent seas.

Numerous findings ofCythere pumila Brady 1866 along the southern Australian and northern Tasmanian shores enabled us to study not only the shell morphology but also the soft parts of the animal. Due to differences in the male copulatory organ it was possible to distinguish two species that in the past were reported as ‘variation’. Further investigations yielded new information aspects on the development of the third frontal muscle scar in hemicytherids. As a result of our investigations the genusAmbolus n. gen. is introduced. The type species of the genus isAmbolus pumilus (Brady 1866) andAmbolus coniunctus n. sp. is described as a new species.

Nearly half of the genera of the family Caligidae possess an evolutionarily novel structure called the "lunule" on the ventral surface of the frontal plate. Lunules are paired cup-like suckers that assist in securing attachment of the copepod parasite to its host. Although present in genera such as Caligus and Pseudocaligus, lunules are absent in other caligid genera such as Lepeophtheirus as well as in more primitive caligiforms such as members of the families Trebiidae and Dissonidae. We compared the morphology and development of the anterior margin of the frontal plates between two caligids, Pseudocaligus fugu and Lepeophtheirus sekii, and a more basal caligiform, Dissonus heronensis (a dissonid), using scanning electron, transmission electron, and laser confocal microscopes. Our observations suggest that the lunules originated as a modification of the marginal membranes of the ancestral frontal plates. We also demonstrated the presence of an anlagen cell population for the lunule and marginal membrane in the developing frontal plate. These primordial cells can be detected as early as the first stage of the chalimus phase. Based on these observations, an evolutionary scenario for the lunule is proposed based on cytological evidence. This case study enhances our understanding of "evolutionary novelty," which is a main focus of contemporary evolutionary developmental biology.

The ostracod genera Parapolycope Klie, 1939 and Kliecope Tanaka, Tsukagoshi & Karanovic, 2014 have a sexually dimorphic upper lip, and males use their lip during courtship. Here we study the male upper lip of 14 species in order to find homologous structures. For this purpose, the lip is divided into six homologous parts, determined by their relative position on the lip and the lip’s position in relation to other body parts. We found that the distal part (‘c’) is the most variable across taxa, probably due to high sexual selection. Six characters of the male upper lip are used in our cladistic analysis, along with another 12, in order to study phylogenetic relationships between Parapolycope species from East Asia. In addition, 18S rRNA is used to reconstruct molecular phylogeny and test the congruence between morphological and molecular data. The recovered topology on all obtained trees is almost identical, emphasising the importance of the male upper lip morphology in interpreting phylogenetic relationships in this peculiar ostracod group. Parapolycope viriosa, sp. nov. and P. widoensis, sp. nov. from marine interstitial habitats in South Korea are described here. To aid further identification of the 12 East Asian Parapolycope species we provide a taxonomic key.

The genus Ishizakiella (Podocopida: Ostracoda) was proposed by McKenzie and Sudijono (1981) for a fossil species from the Plio-Pleistocene of Java. Three extant species of Ishizakiella are reported herein from the river mouths and the upper eulittoral zone in the Japanese Islands. One of them is a new species, I. ryukyuensis, from Okinawa and Iriomote. The chitinous parts and ecology of I. miurensis are described for the first time. The carapace of I. supralittoralis from the northern area, i.e., the Kuril Islands and Hokkaido, has poor ornamentation, simple hingement, and a narrow marginal zone in comparison with other species of Ishizakiella. These particular characters of I. supralittoralis are found in the juveniles of the two other species. In view of their present geographical distributions and fossil records, the species of Ishizakiella in East Asia certainly migrated from the South Pacific region in the Early Pleistocene. Ishizakiella supralittoralis is the latest derivative taxon, since this species is distributed in the northernmost area. The juvenile-like characters of supralittoralis are attributable to paedomorphic evolution.

Four interstitial cobanocytherid species are described from central Japan: Cobanocythere ikeyai sp. nov., Cobanocythere lata sp. nov., Paracobanocythere watanabei sp. nov. and Paracobanocythere grandis sp. nov. The reports of the two new Paracobanocythere species are the second and third for this genus since the original description of P. hawaiiensis Gottwald, 1983. Cobanocythere ikeyai sp. nov., and C. lata sp. nov., from Japan are morphologically more similar to the species of the “lanceolata group” by Gottwald (1983) and C. guttaeformis Gottwald, 1983 from the Galapagos Islands, respectively, rather than to other Cobanocythere species from Japan. The Japanese archipelago (eastern Eurasian Continent) and the Galapagos Islands (north-western South America) are separated by about 15,000 km from each other, and have never been adjoined throughout geological history. This fact, and also the morphological similarities between Cobanocythere species from Japan and the Galapagos Islands, suggests that this genus may have undergone global dispersal at several times in the past. Conversely, the genera Cobanocythere and Paracobanocythere are distributed not only around continents and continental islands but also around oceanic islands such as the Hawaiian and Galapagos Islands. We conclude, therefore, that the cobanocytherids seem to have been able to disperse long distances across oceans.

The migration of thermophilic marine Ostracoda into the Arctic Ocean during the Pliocene indicates that winter and summer ocean temperatures around Arctic margins were ≥ 0 °C and > 3 °C, respectively, and that ice-free conditions existed for most or all of the Arctic. By at least 3.5–3.0 Ma, probably earlier, the opening of the Bering Strait allowed marine organisms to migrate through the Arctic Ocean, mostly from the Pacific Ocean. Migrant taxa such as Cythere, Hemicythere, and Neomonoceratina are known from Pliocene deposits of Alaska and Canada as well as Neogene deposits of the North Pacific and Atlantic oceans. On the basis of ecological and Zoogeographic information on ostracode species from more than 800 modern “core top” samples for the North Atlantic, North Pacific, and Arctic Oceans, we determined winter and summer temperature tolerances for migrant taxa to be at or above about 0 °C and 3 °C. This suggests ice-free summers, and probably, a perennially ice-free Arctic Ocean in some regions. Elevated water temperatures in the Arctic Ocean between 3.5 and 2.0 Ma is supported by evidence for late Pliocene increased meridional heat transport in the North Atlantic Ocean.

Two new interstitial cladocopid ostracods are described from central Japan: Parapolycope oligohalina sp. nov, and Parapolycope spiralis sp. nov. These two species are the third and forth records of the genus Parapolycope Klie, 1936, respectively. Since P. oligohalina sp. nov. inhabits river mouth environments with low salinity at low tides, the wide tolerance to salinity in the species is shown. Myodocopan Ostracoda have so far been considered as a pure marine taxa. The occurrence of P. oligohalina sp. nov. indicates that a few myodocopan ostracods can live in oligohaline environments. The carapace surface covered with puncta of varying size is a unique character of P. oligohalina sp. nov. P. spiralis sp. nov. exhibits a spiral structure in both male copulatory duct and female spermatheca as specific characters. A key to the genera of the Polycopinae is presented.

Antennal podomere homology has not been well documented in podocopid ostracods. Difficulties associated with describing this homology are compounded by the occurrence of specialised podomeres in both cytheroids and bairdioids. Our research establishes the existence of two kinds of aesthetascs shared among multiple higher taxa. Overgrowth “t-setae” are present in males in Cytheroidea, Cypridocopina and Darwinuloidea, and “aesthetasc yc” is found in both sexes in Cytheroidea and Bairdioidea. Homology of the antennal podomeres among all podocopid superfamilies was determined by using the chaetotaxy of these aesthetascs, leading to a description of evolutionary modifications of the podocopid antenna, which suggests that changes in function of the articulation were prompted by the temporal demands of copulatory behavior in each lineage.

Two new ostracod species, Semicytherura maxima n. sp. and S. ikeyai n. sp., both belonging to the S. henryhowel group of the genus, are described. They were collected from Akkeshi Bay in northeastern Japan, and inhabit the marine sediment surface in places deeper than the intertidal zone. Their distributions in northern Japan seem to be influenced by the cold-water Chishima Current (Oyashio). The geological distribution and species diversity were surveyed for each of the subgroups recognized in the S. henryhowei group. The results suggest that these subgroups split from each other in the NW Pacific by the Early Miocene, and that one of them has spread around the Northern Hemisphere, while the other has remained in the NW Pacific since that time.

Cythere japonica was proposed by Hanai (1959) as a new species of the genus Cythere, from the Pleistocene Sawane Formation in Sado Island, Niigata Prefecture, Japan. The characters of carapace were already known, but the appendages have not been previously described. The authors formerly considered that this species should be separate from the genus Cythere sensu stricto because it has twice as many sieve-type pore systems as typical Cythere species, and a markedly higher carapace. The existence of living Cythere japonica in the tidal zone of north-west Japan is confirmed, and its taxonomic position re-examined on the basis of its appendages and the ontogeny of pore systems. The appendages, except for the copulatory organ, are almost identical with those of other Cythere species, and their pore systems share the same pattern in and before the A-4 moult stage. On the basis of these features this species should be retained in the genus Cythere. Phylogenetic relationships are considered on the basis of the ontogeny of pore systems. The abdominal segments of podocopid Ostracoda, which have always been regarded as difficult to observe because of their fusion, are shown clearly by the SEM.

Species of Cythere (Ostracoda, Crustacea) have about one hundred normal pore systems on each valve of the carapace. These can be classified into five types on the basis of morphological features. They were examined in the light of intraspecific variation and interspecific difference. Each of the five pore systems has its own mode of ontogenetic increase in number. Comparison among fourteen Cythere species shows that the distributional patterns are completely identical in the A-3 stage, but that they are classified into four and eight groups in the A-2 and A-1 stages, respectively. In the adult stage the pattern becomes diversified among the fourteen species, though homologous relationships are still recognized between different species. The similarity and difference of the pore patterns, which are traceable until the last ontogenetic stage, can be used to determine phylogenetic relationships. These findings were applied to the reconstruction of phylogeny of the eleven living and three extinct species of Cythere.□Crustacea. Ostracoda, Cythere, Ontogeny. Phylogeny, pore system, pore canal. speciation, laroal morphology.

Two new and one known species belonging to the genus Callistocythere of the family Leptocytheridae from interstitial environments of the Okinawa Islands are fully described. Callistocythere intermedia sp. nov. is regarded as belonging to the C. japonica group, and Callistocythere ryukyuensis sp. nov. belongs to the C. minor group (these groups were established by Hanai 1957 based on carapace morphology). The redescribed Callistocythere ventricostata Ruan & Hao, 1988 clearly differs from known leptocytherid species in the morphologies of the carapace and the male copulatory organ. The habitats of C. intermedia sp. nov. and C. ryukyuensis sp. nov. are found along the shoreline zone and the mid to high tide levels of the littoral zone, respectively, and C. ventricostata is found from the shoreline to the sub-tidal zone. These species are the first global records of interstitial leptocytherids.

Measles epidemic occurred in southern part of Fukushima Prefecture from April 2002 to July 2003. Public Iwase hospital in Sukagawa City was the central hospital in the measles epidemic area and 382 patients with measles were admitted to the hospital during the epidemic. Based on clinical records, age distribution, vaccination history, familiar infection and complications were retrospectively investigated. Moreover, the vaccination rates and their calculating methods in the area were compared and the problems on immunization against measles were discussed. As the result, we found that 1) measles epidemic centered on unvaccinated infants, 2) measles was still serious disease with many complications and sometimes fatal, 3) measles was highly infectious and there was no way for prevention except vaccination, 4) the actual condition of measles vaccination was not reflected exactly by the current calculating methods used for the local health reports by the Ministry of Health Labour and Welfare. For the prevention of measles epidemic, it is necessary to know the exact numbers of patients infected with measles and patients deceased due to measles, to calculate precise vaccination rate, and to form the consensus among parents, physicians and administrators to control measles epidemic by the vaccination.

Amorphous carbon nanorods were synthesized from hollow multiwalled carbon nanotubes (MWCNTs) by low-energy Ar ion irradiation at room temperature. The obtained nanorods were investigated by Raman spectroscopy, transmission electron microscopy (TEM), soft X-ray photoelectron spectroscopy (XPS), and soft X-ray absorption spectroscopy (XAS). It was found that the diameter of the MWCNTs significantly increased with increasing the fluence. Finally, the original hollow structure and the graphite (002) TEM diffraction spots of MWCNTs completely disappeared and a broadening of Raman spectra occurred, indicating the amorphization of MWCNTs. The increase in the diameter by the irradiation can be explained by the bending and the randomization of the broken carbon hexagonal networks, and the accumulation of knocked-on atoms. The XPS and XAS measurements also support the formation of amorphous carbon nanorods.