Abstract
The taxonomically confusing species of sea lice Caligus aesopus Wilson, 1921 and C. spinosus Yamaguti, 1939 are redescribed based on material taken from gills of amberjacks (Seriola spp.) from Korean seas. These two sea lice can be distinguished from each other by the following major differences: (1) the female abdomen of C. aesopus has a lateral constriction in the distal third, but that of C. spinosus is fusiform, without a constriction; (2) the proximal process on the first antennal segment is subcircular distally in C. aesopus, but tapered in C. spinosus; (3) the basis of leg 1 has a small tubercle in C. aesopus, but none in C. spinosus; (4) the protopod (apron) of leg 3 of C. aesopus has an inner patch of less than 15 large spinules, but that of C. spinosus has a patch of more than 25 small spinules; (5) the innermost spine on the third exopodal segment of leg 4 is distinctly longer than the nearby middle spine in C. aesopus, but subequal to the middle spine in C. spinosus; (6) the inner margin of the first maxillipedal segment of the male has four processes in C. aesopus, but three in C. spinosus; and (7) the first maxillipedal segment of the female has a tubercle on the myxal area in C. aesopus, but absent in C. spinosus.References
Fernandez, J. & Villalba, C. (1986) Contribucion al conocimiento del genero Caligus Müller, 1785 (Copepoda: Siphonostomatoida) en Chile. Gayana, Zoology, 50, 37–62.
Hewitt, G.C. (1963) Some New Zealand parasitic Copepoda of the family Caligidae. Transactions of the Royal Society of New Zealand, 4, 61–115.
Ho, J.-S., Nagasawa, K., Kim, I.-H. & Ogawa, K. (2001) Occurrence of Caligus lalandei Barnard, 1948 (Copepoda, Siphonostomatoida) on amberjacks (Seriola spp.) in the western North Pacific. Zoological Science, 18, 423–431.
Humes, A.G. & Gooding, R.U. (1964) A method for studying the external anatomy of copepods. Crustaceana, 6, 238–240.
Hutson, K.S., Ernst, I., Mooney, A.J. & Whittington, I.D. (2007) Metazoan parasiteassemblages of wild Seriola lalandi (Carangidae) from eastern and southern Australia. Parasitology International, 56, 95–105.
Izawa, K. (1969) Life history of Caligus spinosus Yamaguti, 1939 obtained from cultured yellow tail, Seriola quinqueradiata T. & S. (Crustacea: Caligoida). Report of Faculty of Fisheries, Prefectural University of Mie, 6, 127–157.
Johnson, S.C., Treasurer, J.W., Bravo, S., Nagasawa, K. & Kabata, Z. (2004) A review of the impact of parasitic copepods on marine aquaculture. Zoological Studies, 43, 229–243.
Kensley, B. & Grindley, J.R. (1973) South African parasitic Copepoda. Annals of the South African Museum, 62, 69–130.
Lin, C.-L. & Ho, J.-S. (2007) Six species of sea lice (Copepoda, Caligidae) new to Taiwan. Journal of the Fisheries Society of Taiwan, 34, 41–67.
Pillai, N.K. (1963) Copepods parasitic on South Indian fishes -family Caligidae. Journal of Marine Biological Association of India, 5, 68–96.
Sharp, N.J., Poortennar, C.W., Diggles, B.K. & Willis, T.J. (2003) Metazoan parasites of yellowtail kingfish, Seriola lalandi lalandi, in New Zealand: prevalence, intensity, and site preference. New Zealand Journal of Marine and Freshwater Research, 37, 273–282.
Shiino, S.M. (1960) Copepods parasitic on the fishes collected on the coast of Province Shima, Japan. Report of the Faculty of Fisheries, Prefectural University of Mie, 3, 471–500.
Wilson, C.B. (1921) Report on the parasitic Copepoda collected during the survey of the Juan Fernandez Islands, 1916–1917. Natural History of the Juan Fernandez & Easter Islands, 3, 69–74, pls. 2–4.
Yamaguti, S. (1939) Parasitic copepods from fishes of Japan. Part 5. Caligoida. III. In: Volume Jubilare pro Prof. Sadao Yoshida, 2, 443–487, pls. 14–33.
Yamaguti, S. & Yamasu, T. (1960) New parasitic copepods from Japanese fishes. Publications of the Seto Marine Biological Laboratory, 8, 141–152, pls. 10–12.