Currently, I am undertaking a taxonomic revision of the genus Argulus and related genera because these parasites are often difficult to identify with keys and other literature available at present.
One useful tool for studying Argulus and other invertebrates is scanning electron microscopy (SEM), which allows one to observe minute details of an organism's exterior structure (see photo of a sensillum at right).
I will be happy to identify any Argulus persons would like to send, and the specimens would be helpful for my research. I like to preserve specimens in 70% ethyl alcohol and usually record information such as: name of the host, position on host, locality, date, and collector(s) name(s). I can be contacted at the e-mail address below.
William J. Poly
Department of Ichthyology
California Academy of Sciences
Argulus (Crustacea: Branchiura)
The genus Argulus (Crustacea: Branchiura) has a worldwide distribution and is known from Africa, Europe, Asia, Australia, and North, Central, and South America (Ringuelet, 1943; Fryer, 1968; Yamaguti, 1963; Hewitt and Hine, 1972; Byrnes, 1985; Heegaard, 1962). Twenty-three species were recognized in marine and fresh waters of the United States by Cressey (1972), but more recently, 32 species and subspecies were considered valid (McLaughlin et al., 2005). Argulus is an interesting genus of parasite that is ectoparasitic, primarily on fishes. The classification according to Martin and Davis (2001) with amendments by W.J. Poly is as follows:
Phylum Arthropoda Subphylum Crustacea Brünnich, 1772 Class Maxillopoda Dahl, 1956 Subclass Branchiura Thorell, 1864 Order Arguloida Wilson, 1932 Family Argulidae Rafinesque, 1815 Genus Argulus Müller, 1785 Genus Dolops Audouin, 1837 Genus Chonopeltis Thiele, 1900 Genus Dipteropeltis Calman, 1912
Argulus contains about 129 valid species and occurs in marine, estuarine, and freshwater habitats, whereas the other three genera, occurring only in freshwater, have one valid species (Dipteropeltis; South America), 14 valid species (Chonopeltis; Africa), and 13 valid species (Dolops; South America, Africa, Tasmania) (Poly, 2008, unpubl. data). One species of Dolops occurs in Tasmania (Fryer, 1969).
The flat, shield-like part of the body is the carapace and it is fused with the head and partially covers the thorax. Two movable compound eyes are present on the head region and are usually conspicuous. The abdomen is the tail-like part hanging off the back end. They have four pairs of swimming legs. A strikingly pigmented species from South America is Argulus multicolor (see figure below). Three species documented in Europe are Argulus coregoni, Argulus foliaceus, and Argulus japonicus . Argulus japonicus has been introduced all over the world, primarily due to stockings of goldfish (Carassius auratus) and also carp (Cyprinus carpio). A North American species, Argulus appendiculosus, has been erroneously reported in Britain according to Fryer (1982).
Argulus coregoni has been found on brown trout (Salmo trutta) in the River Clyde in Scotland (Campbell, 1971). Argulus coregoni also occurs in Japan and was studied in great detail by Dr. Shigeru Shimura (see Shimura, 1981). Argulus foliaceus also occurs on brown trout, as well as stickleback (Gasterosteus aculeatus), roach (Rutilus rutilus), perch (Perca fluviatilis), carp (Cyprinus carpio), tench (Tinca tinca), pike (Esox lucius) and bream (Abramis brama).
Argulus multicolor Schuurmans Stekhoven, Jr., 1937 (Dorsal and ventral views of female) (from Schuurmans Stekhoven, Jr., 1937)
Argulus attach to fishes with the aid of two suction cup-like appendages (their first maxillae) and abundant little spines located over much of their underside. They have a long, slender preoral sting that they use to pierce the fishes skin and inject a toxin (or anticoaggulant), then they use their mouth and mandibles to consume the blood, mucous, tissue at the puncture site. They can be damaging to fishes mainly due to fungal infections that attack at the puncture sites made by the Argulus, and they also can transmit fish viral diseases and other fish parasites. There are several reports of hundreds of Argulus occurring on a single fish, and Fryer (1982) stated that a 28 cm tench in Europe was found with 4,250 Argulus attached! This case is very extreme though. Adults can survive about two weeks without a fish host, and newly hatched larvae can survive one or two days without a host (personal observation).
Argulus may lay several hundred tiny eggs in a single row (often), but sometimes in two or more rows or a cluster on a hard surface (rock, stick, etc.), and the eggs hatch anywhere from two weeks to a month later. Argulus breed several times during the year.
A case of Argulus laticauda clinging to a human eye has been reported; a ten-year old boy was swimming open-eyed in a Maryland River, and the Argulus happened to attach and was later removed without complications, but as most things "in" or on your eye, it was irritating (Hargis, 1958).
(cited in text above plus additional ones for the reader's information)
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Bower-Shore, C. 1940. An investigation of the common fish louse, Argulus foliaceus (Linn.). Parasitology 32(4): 361-371.
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Byrnes, T. 1985. Two new Argulus species (Branchiura: Argulidae) found on Australian bream (Acanthopagrus spp.). Australian Zoologist 21(7): 579-586.
Campbell, A.D. 1971. The occurrence of Argulus (Crustacea: Branchiura) in Scotland. Journal of Fish Biology 3(2): 145-146.
Causey, D. 1960. II. "Creepin, blastit wonner" or on the misidentification of common Argulus of freshwater fish. Turtox News 38(2): 70-75.
Cressey, R.F. 1972. The genus Argulus (Crustacea: Branchiura) of the United States. Biota of Freshwater Ecosystems, U.S. Environmental Protection Agency Identification Manual 2: viii + 1-14.
Cressey, R.F. 1978. Marine Flora and Fauna of the Northeastern United States. Crustacea: Branchiura. NOAA Technical Report Circular 413: 1-10.
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Fryer, G. 1982. The parasitic Copepoda and Branchiura of British freshwater fishes: A handbook and key. Freshwater Biological Association, Scientific Publication No. 46. 87 p.
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Hewitt, G.C. and P.M. Hine. 1972. Checklist of parasites of New Zealand fishes and of their hosts. New Zealand Journal of Marine and Freshwater Research 6(1/2): 69-114.
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Lobo Peralta, Augusto Solano, José Roberto Carvalho, Jr., Edilson Matos, and Nicolau Maués Serra-Freire. 1998. Ocorrência de Argulus juparanaensis Lemos de Castro, 1950 (Branchiura: Argulidae) em arraia de fogo Potamotrygon motoro (Müller & Henlé, 1841) (Rajiforme [sic]: Potamotrygonidae) no Igarapé do
Salito, Município de Cachoeira do Arari, Marajó, Estado do Pará. Entomología y Vectores 5(1): 49-54.
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Martin, P. Mikkelsen, E. Nelson, W.A. Newman, R.M. Overstreet, W.J. Poly, W.W. Price, J.W. Reid, A. Robertson, D.C. Rogers, A. Ross, M. Schotte, F.R. Schram, C.-T. Shih, L. Watling, G.D.F. Wilson, and D.D. Turgeon. 2005. Common and scientific names of aquatic invertebrates from the United States and Canada: crustaceans. American Fisheries Society, Special Publication 31, Bethesda, Maryland. i-xiii + 1-545 pp.
Meehean, O.L. 1940. A review of the parasitic Crustacea of the genus Argulus in the collections of the United States National Museum. Proceedings of the
United States National Museum 88: 459-522.
Meyer-Rochow, V.B., D. Au, and E. Keskinen. 2001. Photoreception in fishlice (Branchiura): The eyes of Argulus foliaceusLinné, 1758 and A. coregoniThorell, 1865 [sic, 1864]. Acta Parasitologica 46(4): 321-331.
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Monod, Th. 1928. Les Argulidés du musée du Congo. Inventaire systématique, comprenant la description d'Argulus Schoutedeni nov. sp., et Liste générale critique des Branchiures africains, tant marins que dulcaquicoles. Revue de Zoologie et de Botanique Africaines 16(3): 242-274.
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Paperna, I. and R.M. Overstreet. 1981. Parasites and diseases of mullets (Mugilidae), Pages 411-493 In: O.H. Oren (ed.), Aquaculture of grey mullets (International Biological Programme 26). Cambridge University Press, Cambridge, Great Britain. 507 pp.
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Poly, W.J. 1997. Host and locality records of the fish ectoparasite, Argulus (Branchiura), from Ohio (U.S.A.). Crustaceana 70(8): 867-874.
Poly, W.J. 1998. New state, host, and distribution records of the fish ectoparasite, Argulus (Branchiura), from Illinois (U.S.A.). Crustaceana 71(1): 1-8.
Poly, W.J. 1998. Argulus purpureus (Risso, 1827), a junior synonym of Argulus vittatus (Rafinesque-Schmaltz, 1814) (Branchiura: Arguloida). Crustaceana 71(6): 628-632.
Poly, W.J. 2003. Argulus ambystoma, a new species parasitic on the salamander Ambystoma dumerilii from México (Crustacea: Branchiura: Argulidae). Ohio Journal of Science 103(3): 52-61.
Poly, W.J. 2005. Argulus yucatanus n. sp. (Crustacea: Branchiura) parasitic on Cichlasoma urophthalmus from Yucatan, Mexico. Gulf and Caribbean Research 17: 1-13.
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