Vol. 62, 2023
(update: 2023.2.21)
Molecular and Morphological
Characterizations of the Fish Parasitic Isopod Mothocya parvostis
(Crustacea: Cymothoidae) Parasitizing Optional Intermediate Hosts:
Juveniles of the Cobaltcap Silverside Hypoatherina tsurugae and
Yellowfin Seabream Acanthopagrus latus
Hiroki
Fujita1,* , Kentaro Kawai1,
Diego Deville1, and Tetsuya Umino1
doi:-
1Graduate
School of Integrated Sciences for Life, Hiroshima University, 1-4-4
Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8528, Japan.
*Correspondence: E-mail: hirokifujita1231@gmail.com (Fujita).
E-mail: kawai-ken@hiroshima-u.ac.jp (Kawai); diegodeville1608@gmail.com
(Deville); umino@hiroshima-u.ac.jp (Umino)
(Received 16 June 2022 / Accepted 10 February 2023 / Published -- 2023)
Communicated by Benny K.K. Chan
Mothocya parvostis
(Isopoda: Cymothoidae) is a parasitic crustacean that infests the
opercular cavities of fishes. Its main final host is the Japanese
halfbeak, Hyporhamphus sajori. However, M. parvostis also infests the black sea bream, Acanthopagrus schelgelii,
as an optional intermediate host. Understanding the use of optional
intermediate hosts is important for understanding the life history of
Cymothoidae, and further information should be obtained. In this study,
we aim to investigate the life cycle of M. parvostis. We collected and examined 20 mancae and 144 juveniles of M. parvostis from 129 cobaltcap silversides, Hypoatherina tsurugae, and 494 yellowfin seabreams, Acanthopagrus latus. Molecular analysis of the cytochrome c oxidase
subunit I gene and 16S rRNA genes revealed that cymothoid mancae and
juveniles from the two fish species were identified to be M. parvostis. All M. parvostis on H. tsurugae and A. latus might be mancae or juveniles, with no adult parasites; thus, H. tsurugae and A. latus juveniles were optional intermediate hosts of M. parvostis. In the results of morphological description, M. parvostis juveniles infesting the final host H. sajori lacked swimming setae, while juveniles parasitizing the two optional intermediate hosts had them. Mothocya parvostis
mancae infested juveniles of both species just after metamorphosis,
grew with the host, and detached from the fish as juveniles continued
growing. The parasitic status of M. parvostis in the three optional intermediate hosts indicated that M. parvostis
likely reproduced from June to December, and different optional
intermediate hosts were used depending on the time of year in Hiroshima
Bay. Therefore, a parasitic strategy involving optional intermediate
hosts might increase the infestation success of M. parvostis to H. sajori.
Key words: Life cycle, Manca, New host record, Parasitic cymothoid, Prevalence.
Citation:
Fujita H, Kawai K, Deville D, Umino T. 2023. Molecular and
Morphological characterizations of the fish parasitic isopod Mothocya
parvostis (Crustacea: Cymothoidae) parasitizing optional intermediate
hosts: juveniles of the cobaltcap silverside Hypoatherina tsurugae and
yellowfin seabream Acanthopagrus latus. Zool Stud 62:21.

Supplementary
materials: Table S1
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