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Avitocaligus evoxymetoponicola nov. sp. (Copepoda, Siphonostomatoida, Caligidae) is described as the second representative of the genus based on specimens of both sexes recovered from the branchial and nasal cavities of Poey's scabbardfish, Evoxymetopon poeyi Gunther, 1887 (Trichiuridae), caught off Cape Muroto, on the Pacific coast of southern Japan. This new species is easily distinguishable from the type species, A. assurgericola Boxshall & Justine, 2005, parasitic on the razorback scabbardfish, Assurger anzac (Alexander, 1917), by the contour of the lateral and dorsoposterior plates of the genital complex and the ventral plates of the first abdominal somite, in addition to the possession of postantennal processes and marginal membranes on the frontal plates. The description of the male is given here for the first time for this genus. The maxilliped of the male is unique in having a rod-like myxal process. [ABSTRACT FROM AUTHOR]

A new species of copepod, Sarcotretes umitakae sp. n., of the siphonostomatoid family Pennellidae is described based on female specimens from the rattail Coelorinchus jordani Smith and Pope (Actinopterygii: Gadiformes: Macrouridae) caught in the East China Sea. This species is characterized by exhibiting the following characters: the large proboscis projects strongly; the head bears paired lateral processes which are bulbous and taper into a slender horn; the twisting neck is significantly longer than the trunk; and the trunk bears an anterior constriction with a reduced abdomen [ABSTRACT FROM AUTHOR]

Four new species of Peniculisa Wilson, 1917, are described from marine fishes caught in coastal waters of southwestern Japan. Peniculisa elongata n. sp., Peniculisa crassa n. sp., and Peniculisa uchinah n. sp. are distinguishable from Peniculisa furcata (Krøyer, 1863), Peniculisa bellwoodi Boxshall, 1989, and Peniculisa wilsoni Radhakrishnan, 1977, in the lack of rami on legs 1 to 4, the lack of leg 5, and the possession of a trunk with prominent anterior shoulders. Peniculisa elongata n. sp. is separated from the remaining 2 known and 3 new congeners, Peniculisa bicaudata Shiino, 1956, Peniculisa shiinoi Izawa, 1965, P. crassa n. sp., Peniculisa ohirugi n. sp., and P. uchinah n. sp. by a pair of long, slender caudal processes, a compact cephalothorax, and its trunk with posteroventral lobes projecting posteriorly. Peniculisa crassa n. sp. can be discriminated from them by its pair of short, thick caudal processes, a comparatively large and thick cephalothorax in relation to its body, and its abdominal processes widest at base. Peniculisa uchinah n. sp. is distinguished from all other congeners by the possession of a pair of relatively long, slender, and proportionately long caudal processes, and a long abdominal process widest near the posterior end. Peniculisa ohirugi n. sp. is identified by a pair of long, divergent abdominal processes extending the tip of caudal rami, and by the location of leg 4 on the neck region. [ABSTRACT FROM AUTHOR]

Eight species of pandarid copepods are redescribed based on specimens recovered from six species of Japanese elasmobranchs. These are Pandarus cranchii Leach, 1819, P. smithii Rathbun, 1886, Gangliopus pyriformis Gerstaecker, 1854, Pseudopandarus gracilis Kirtisinghe, 1950, Dinemoura latifolia (Steenstrup & Lütken, 1861), Echthrogaleus coleoptratus (Guérin-Méneville, 1837), E. denticulatus Smith, 1874, and Nesippus orientalis Heller, 1868. In P. cranchii, both sexes of copepodid IV and V are described, one of them retains the frontal filament. The postnaupliar juveniles preceding the adult are referred to here as copepodid stages instead of chalimus. The presence of the postantennal process was verified in all species here dealt with, though it is replaced by an additional adhesion pad in D. latifolia. The depression, seemingly acting as the sucker, was found in N. orientalis on the female leg 3 basis. [ABSTRACT FROM AUTHOR]

The post-embryonic development of the copepod Pseudocaligus fugu is described. This sea louse only parasitizes toxic pufferfish, and causes commercial loss of cultured Takifugu rubripes in Japan. Two naupliar, one copepodid and four chalimus stages preceding the adult are recognized in the species. The development pattern is similar to that of Caligus except for the suppression of leg 4 in the early chalimus phase. Pseudocaligus fugu lacks any preadult stage, as in Caligus, but contrasts with Lepeophtheirus species in which two preadult stages are reported. The nature of the metamorphic changes in size and even in degree of expression of articulations can occur without moulting. The validity of some chalimus stages recognized in Lepeophtheirus species is questioned. Growth and egg production in P. fugu were obtained in the laboratory. Pseudocaligus fugu attained adulthood 9 days after the infective copepodid attached to the host. [ABSTRACT FROM AUTHOR]

The article examines the prevalence of adult females Phrixocephalus umbellatus parasitic on the eyes of Paralichthys olivaceus, which can be found at the western part of the sea of Japan. Paralichthys olivaceus or Japanese flounders were collected by nets of Kami-cho, Mitaka, Hyogo Prefecture from March 2004 to March 2005. In the study, infected individuals of the Japanese flounder was classified as the first and/or second year classes on the basis of the body length and weight. It is recommended that information on seasonal changes in prevalence and intensity and breeding of the parasite infecting Japanese flounder should be developed.

Based on specimens from the gill cavities of one Platichthys stellatus individual collected in the Sea of Japan, we investigated the taxonomic status of the enigmatic caligid genus Pseudolepeophtheirus and its type species, Pseudolepeophtheirus longicauda. In a maximum likelihood (ML) tree based on 18S rRNA gene sequences, the sequence from our sample was nested in a well-supported Lepeophtheirus clade, along with the type species, confirming that Pseudolepeophtheirus should be considered a junior synonym of Lepeophtheirus; our morphological data support this synonymy. Although a previous study had synonymized Pseudolepeophtheirus longicauda with Lepeophtheirus parvicruris, we found that the former differs morphologically from the latter in having a short leg-4 exopod, with the articulation between the first and second segments not evident (the shape of the posterior striated membrane on the leg-2 intercoxal sclerite also differs between two species), and detected slight differences in 18S rRNA sequences between two taxa. We thus concluded that this synonymy is invalid, and reinstate Lepeophtheirus longicauda as a valid species. A ML analysis of COI sequences from Pl. stellatus (the host fish for both L. longicauda and L. parvicruris) showed the host species to comprise distinct northwestern- and northeastern-Pacific clades. Lepeophtheirus longicauda is distributed in the northwestern Pacific and L. parvicruris in the northeastern Pacific, indicating co-divergence of the two copepod species with the host lineages., (Copyright © 2020 Elsevier B.V. All rights reserved.)