Multivalvulid myxosporeans of the genera Kudoa Meglitsch, 1947 and Unicapsula Davis, 1924 (Cnidaria: Myxozoa) are often the cause of unsightly cyst formation or postmortem myoliquefaction in the trunk muscle of commercial marine fish, which reduces the market value of infected individuals. Twenty species (18 Kudoa spp. and two Unicapsula spp.) have been recorded from carangid fish, although the majority of them, excluding polyxenous species, such as K. amamiensis Egusa et Nakajima, 1980, K. iwatai Egusa et Shiomitsu, 1983, K. nova Naidenova, 1975, K. quadratum (Thélohan, 1895) and K. yasunagai (Hsieh et Chen, 1984), are limited to a single or a few fish species. We report the occurrence of macroscopic cysts of Kudoa trachuri Matsukane, Sato, Tanaka, Kamata et Sugita-Konishi, 2011 in the trunk muscle of four new host fish species, i.e., Pseudocaranx dentex (Bloch et Schneider), Decapterus akaadsi Abe, D. muroadsi (Temminck et Schlegel) and Decapterus tabl Berry, fished from the Philippine Sea (Northwest Pacific Ocean), off southwestern of Japan. Myxospore morphology and genetic characteristics of the ribosomal RNA gene (rDNA) of these isolates were consistent with previous records of K. trachuri from Trachurus japonicus (Temminck et Schlegel) from around Japan. In addition, a new species of Kudoa that forms long filamentous pseudocysts in trunk myofibres was found in four of the six D. tabl collected in this study. We describe Kudoa longichorda sp. n. for this new isolate, based on its morphology of subquadrate myxospores with four shell valves and polar capsules and with small dimensions (length 4.3-5.5 µm, width 6.0-6.8 µm, thickness 4.8-6.3 µm, polar capsule length 2.3-3.1 µm, polar capsule width 1.1-1.7 µm), as well as 18S and 28S rDNA sequences distinct from those of known species.
Examinations of 29 specimens of the catfish Liobagrus reini Hilgendorf (Siluriformes: Amblycipitidae), a species endemic to Japan, collected from the Sho River, Toyama Prefecture, in central Honshu, revealed the presence of four species of helminth parasites: Plagioporus honshuensis sp. n. (Trematoda), Rhabdochona coronacauda Belouss, 1965, H. japonica Moravec, 1975 and Mexiconema liobagri sp. n. (all Nematoda). The new opccoelid trematode P. honshuensis is characterized mainly by the extent of vitelline follicles, the size ratio of the suckers (1 : 1.7-2.1), the situation of testes near the middle of the body and by the structure, size and shape of the cirrus sac. Allopodocotyle Pritchard, 1966 is considered a junior synonym of Plagioporus Stafford, 1904. The males of R. japonica are described for the first time and conspeciftc females are redescribed; this species is a specific parasite of L. reini. The principle hosts of R. coronacauda are cyprinids and, therefore, its finding in the catfish may indicate an accidental infection; L. reini represents a new host record. M. liobagri (only females were found) from the host’s abdominal cavily is the second known species of this dracunculoid genus, being characterized by the position of the excretory pore and the number (1) of caudal processes in the female. The recorded helminths are briefly described and illustrated and problems of their systematic status are discussed.
Adalia bipunctata is a well-known predaceous ladybird distributed in Europe, Central Asia and North America. This species has not been recorded in Japan. Recently, we found this species in the Osaka Bay area in central Japan, and assume that it was imported with goods such as timber by ships. We studied the life history and the distribution in the Osaka Bay area since the initial discovery. The larvae and adults preyed on aphids (mainly, Periphyllus viridis) on trees such as Acer buergerianum and Rhaphiolepis umbellata. The over-wintered adults appeared in March and laid eggs. The adults emerged in spring, and were in the rolled leaves throughout the rest of the year. Thus, in Japan this ladybird is univoltine with long inactivity in adult. The life history of Japanese population of A. bipunctata differs considerably from other areas where populations are multivoltine. The developmental threshold was estimated to be 6.3°C and the sum of effective temperatures was 322.6 day-degrees for the period from egg to adult emergence. Predation on prepupae of A. bipunctata by the larvae of native species such as Harmonia axyridis was observed occasionally.
The morphology of two Salvelinema Trofimenko, 1962 species, S. salmonicola (Ishii, 1916) and S. walkeri (F.kbaum, 1935), swimbladder nematodes of salmonids, was studied in detail, including scanning electron microscopy (SEM), on the basis of newly collected materials from Oncorhynchus masou, О. mykiss and Salvelinus malma from Japan and from Oncorhynchus ciarki, О. kisulch and O. nerka from North America (Vancouver Island, B.C., Canada and Gulf of Alaska). Both nematode species proved to be morphologically very similar, differing substantially in the numbers and arrangements of egg filaments. Deirids were described for the first time for Salvelinema. Salvelinema iwana (Fujita, 1928), S. amemasu (Fujita, 1939), S. kosugii (Fujita, 1939), S. oncorhynchi (Fujita, 1939) and S. salvelini (Fujita, 1939) (= S. ishii (Fujita, 1941)) were synonymised with S. salmonicola. Comephoronema Layman, 1933 is re-erected as a valid genus related to Salvelinema.
We encountered two cases of infection with large female nematodes of the genus Philometra Costa, 1845 in the body cavity of a map puffer Arothron mappa (Lesson) caught off Okinawa, Japan, and a blackspotted puffer Arothron nigropunctatus (Bloch et Schneider) caught off Queensland, Australia, both reared in aquariums in Japan. No morphological difference was observed between the nematodes from A. mappa and A. nigropunctatus. We identified the nematodes as Philometra pellucida (Jägerskiöld, 1893) based on their morphology. The sequences of the nematodes from both hosts were identical to each other (1,643 bp) and formed a clade with other 17 nematodes belonging to the genera Philometra and Philometroides Yamaguti, 1935 with high bootstrap value (bp = 100). It is the first time that the genetic data on P. pellucida are provided. Philometra robusta Moravec, Möller et Heeger, 1992 is synonymised with the former species.