Benedenia seriolae ( Yamaguti, 1934 ) Meserve, 1938

Whittington, I. D., Deveney, M. R. & Wyborn, S. J., 2001, A revision of Benedenia Diesing, 1858 including a redescription of B. sciaenae (van Beneden, 1856) Odhner, 1905 and recognition of Menziesia Gibson, 1976 (Monogenea: Capsalidae), Journal of Natural History 35 (5), pp. 663-777 : 728-732

Benedenia seriolae ( Yamaguti, 1934) Meserve, 1938

(®gure 30)

Synonym. Epibdella seriolae Yamaguti, 1934 .

Material studied. MPM: No. 22760 (holotype) (1 slide, 1 individual) ex body surface of Seriola aureovittata (Temminck and Schlegel) (5 Seriola lalandi Valenciennes in Cuvier and Valenciennes, see Smith-Vaniz et al., 1990) ( Carangidae ) from the Inland Sea, Japan; GCK: (2 slides, 2 individuals) ex skin of Seriola grandis (Castelnau) (5 S. lalandi , see Smith-Vaniz et al., 1990) ( Carangidae ) from CoOEs Harbour, NSW, Australia; (1 slide, 1 individual) ex skin of Seriola quinqueradiata (Temminck and Schlegel) (Carangidae) from a ®sh farm in Shirahama, Japan; KR: (1 slide, 1 individual) ex skin of Seriola grandis (5 S. lalandi ) ( Carangidae ) from CoOEs Harbour, NSW, Australia; QM: Nos G213160±87 (27 slides, 27 specimens) ex skin of Seriola lalandi (Carangidae) from Manly Oceanarium (August 1992), Manly, New South Wales, Australia; QM: G212080 ±86 (7 slides, 7 individuals) ex skin of Seriola sp. (Carangidae) from Antofagasta, Chile; USNPC: No. 80213 (1 slide, 1 individual) from Cantherines pardalis (probably Cantherhines pardalis ) ( Monocanthidae ) from Okinawa, Japan of Dyer et al. (1989).

Comparative measurements of some material listed above and morphometrics from Yamaguti (1934) are presented in table 7.

Observations. The original description of B. seriolae by Yamaguti (1934) has been supplemented by Hoshina (1968) and Kearn (1992) with specimens obtained from ®shes in Japan. We have incorporated new material of B. seriolae from Australia (30 specimens), material deposited by Whittington (1996) from Australia and have included specimens reported from Chile that were identi®ed previously as Neobenedenia melleni (see Whittington and Horton, 1996). Altogether, our reappraisal of B. seriolae is based on the holotype and 40 other specimens, 10 of which were immature.

± Indicates that no measurements were presented for these characters by this source.

Benedenia seriolae exceeds 5 mm in length and can attain 10±12 mm in length and is, therefore, a large species (®gure 3A); specimens from Chile are consistently larger (table 7). The large anterior attachment organs are similar in size or larger than the pharynx. The accessory sclerites are large and located centrally on the haptor. The tendons are shown in ®gures 30A, E. The anterior hamuli are elongate and strongly recurved distally (®gure 30A, C, E, G); the posterior hamuli are relatively small (®gure 30A, D, E, H). In most but not all material, the proximal ends of the anterior hamuli just overlap the proximal ends of the accessory sclerites (®gure 30A, E). In some material from an outbreak on Seriola lalandi in 1992 at Manly Oceanarium in Sydney, NSW, Australia, the large haptoral sclerites, and in particular, the accessory sclerites and anterior hamuli, are distorted, reduced in size or even absent. Neither Yamaguti (1934) nor Kearn (1992) described details of the marginal valve. An incomplete description from new material is: narrow posteriorly with one lobe between hooklets of pair II, between hooklet II and an indentation near the posterior hamulus and between this indentation and hooklet III; one lobe each was observed between hooklets III and IV, IV and V, V and VI and VI and VII; between hooklets VII and VIII, there is one large lobe apparently comprising at least 10±12 smaller, fused lobes and a large lobe between hooklets of pair VIII, but the number of small lobes comprising this could not be determined. The marginal valve is substantially wider anteriorly (®gure 30A, E).

The most complete account of the reproductive system of B. seriolae is that of Kearn (1992) from a combination of studies on live parasites and freshly preserved material. Kearn noted features not described previously such as: presence of accessory gland ducts entering the accessory gland reservoir in two separate tracts; dorsoventral columnar structures in the testes and germarium; presence of an internal fertilization chamber in the germarium; wide dorsal vaginal pore with a cone-shaped vestibule tapering proximally to a duct with a narrow, constricted lumen before widening again. Kearn did not observe glands of Goto. Our analysis of new material from Australia con®rms Kearn’s observations except that in few specimens did we observe a cone-shaped vestibule in the vagina. The penis is a conspicuous, muscular organ accommodated inside an elongate canal with little muscle in its wall. The accessory gland reservoir is prominent and in some specimens, appears to have a thickened wall.

The voucher specimen deposited by Dyer et al. (1989) from Cantherines pardalis (Monocanthidae) from Okinawa is not B. seriolae . This specimen has large haptoral sclerites with shapes and dimensions of overlap that are incongruous with previous descriptions of B. seriolae . Furthermore, this apparently adult specimen is small and possesses large, clearly visible glands of Goto. This specimen is not recognizable as a described species of Benedenia . It likely represents an undescribed species of the genus.

Type-host and locality. Seriola aureovittata (5 Seriola lalandi , see Smith-Vaniz et al., 1990) ( Carangidae ), Inland Sea, Japan.

Published records. Yamaguti (1934); Kubota and Takakuwa (1963); Harada (1965); Hoshina and Matsusato (1967); Kasahara (1967); Hoshina (1968); Iwata (1990); Kearn (1992); Whittington (1996).

Descriptions. Yamaguti (1934); Iwata (1990); Kearn (1992).

Published host records. Carangidae : Seriola aureovittata (5 Seriola lalandi ) (see Yamaguti, 1934); Seriola quinqueradiata (see Kubota and Takakuwa, 1963; Harada, 1965; Hoshina and Matsusato, 1967; Kasahara, 1967; Hoshina, 1968; Iwata, 1990; Kearn, 1992); Seriola lalandi (see Iwata, 1990; Whittington, 1996); Seriola sp. (see Whittington and Horton, 1996).

Site . Body surfaces.

Distribution. Australia: CoOEs Harbour (Whittington, 1996); Manly (Whittington, 1996); North Head, NSW (Whittington, 1996). Chile: Antofagasta ( Whittington and Horton, 1996). Japan: Inland Sea ( Yamaguti, 1934; Iwata, 1990); Uchiura, Numazu City ( Hoshina, 1968); Coast of Kagosima Prefecture ( Iwata, 1990); Kinki ( Harada, 1965); Mie Prefecture ( Kubota and Takakuwa, 1963); Shirahama, Wakayam a Prefecture (Kearn, 1992).

Remarks. Whittington (1996) ®rst identi®ed material from S. lalandi in Australia as B. seriolae and noted that S. lalandi was a new host record. We have subsequently become aware that S. aureovittata , the host from which Yamaguti (1934) described B. seriolae , is a synonym of S. lalandi (see Smith-Vaniz et al., 1990). Our redescription has been aided greatly by the discovery of Australian material. This species of monogenean can be distinguished by: its large size; large, centrally located accessory sclerites (®gure 30); long anterior hamuli which are recurved distally; relatively small posterior hamuli (®gure 30); and vagina opening dorsally with large cone-shaped distal vestibule. The vagina as described by Kearn (1992) was not clear in most of our preserved material, but this presumably reēcts the fact that he studied living parasites in which many features are more conspicuous than in ®xed material.

Benedenia seriolae most closely resembles B. hendor i, but the characters provided by Price (1938) to distinguish the two species are poor and equivocal. Until further studies are made on B. hendor i, we suggest that it and B. seriolae remain as separate species although we suspect that future investigations using fresh material may indicate that B. hendor i and B. seriolae are synonymous.

Benedenia seriolae is reported from Japan, the Paci®c coast of Australia and the Paci®c coast of South America. This species appears capable of infecting several species of carangid hosts indicating that host-speci®city may be broad within this ®sh family. This species does not, however, appear to display host-speci®city as low as B. epinepheli or B. hawaiiensis which can infect many ®sh species across families and orders. In culture, B. seriolae has caused severe losses to stocks of yellowtail, Seriola quinqueradiata , in Japan (see Egusa, 1983). The extension of the natural range of this monogenean is important in this respect for future ventures to culture its carangid hosts. The specimens from Manly, NSW, Australia were causing health problems to their hosts in the Public Aquarium. In Japan, the parasite has only once been recorded from the wild, by Yamaguti (1934) (see Kearn, 1992).