Benedenia synagris Yamaguti, 1953

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 : 732-733

Benedenia synagris Yamaguti, 1953

(®gure 31)

Material studied. MPM: No. 22767 (holotype and 2 paratypes) (1 slide, 3 individuals) ex gills of Synagris sp. (5 Nemipterus sp. , see Russell, 1990) ( Nemipteridae ; see Jordan, 1963) from Macassar, Celebes, Indonesia; USNPC: No. 80212 (voucher) (1 slide, 1 individual) ex gills of Arothron mappa (Lesson) (Tetraodontidae) from Okinawa, Japan ( Dyer et al., 1989).

Observations. Yamaguti (1953) based his original description of B. synagris on three mature specimens. All material we examined was of limited value because the specimens are of poor quality and Yamaguti’s material, in particular, may have deteriorated with age. Benedenia synagris is a small (less than 2 mm long) species (e.g. ®gure 3C). The accessory sclerites are relatively large in comparison with the size of the haptor; tendons pass through their proximal bi®d ends (®gure 31A). The anterior hamuli are strongly recurved and have a broad root (®gure 31A). The posterior hamuli have a paddle-shaped root but bear a strongly hooked distal tip (®gure 31A). The proximal ends of the anterior hamuli overlap with the proximal ends of the accessory sclerites in two of the three type specimens (e.g. ®gure 31A), and the distal tips of the anterior hamuli overlap the posterior hamuli for half to two-thirds of their length (®gure 31A). The marginal valve has: one lobe between hooklets of pair II; two lobes between hooklets II and III; one lobe between hooklets III and IV, IV and V, V and VI, and VI and VII (®gure 31A); no other details could be determined accurately.

The poor quality of the type material has not enabled any comment on details of the female reproductive system as described by Yamaguti (1953) which included a large ootype (®gure 28 of Yamaguti, 1953), a uterine pore separate from the male genital pore and a vagina. Features described by Yamaguti and which could be determined from type material include the presence of`numerous rounded gland cells’ between pharynx and anterior attachment organs (these gland cells diOEer in appearance from the vitelline follicles; ®gure 31B) and a band of vitellarium between germarium and testes. We have noted the following features not described by Yamaguti: anterior attachment organs appear well-demarcated from the body and are anterolaterall y displaced; testes are widely separated; glands of Goto are clearly visible (®gure 31B). However, the appearance of the anterior attachment organs and the widely separated testes could be due to eOEects of ¯attening and ®xation during preparation. Yamaguti, however, ¯attened most material he deposited and as such, we consider it likely that all such specimens are comparable.

We also examined a voucher specimen of poor quality recorded from the gills of Arothron mappa (Tetraodontidae) from Okinawa, Japan by Dyer et al. (1989). We think this specimen is not B. synagris because shapes of the haptoral armature and proportions of the haptoral sclerites to the size of the haptor and to the body are diOEerent and the testes are not widely separated. We regard it likely that this is a specimen of a new, as yet, undescribed Benedenia species.

Type-host and locality. Synagris sp. (5 Nemipterus sp. ) ( Nemipteridae ; see Jordan, 1963), Macassar, Celebes, Indonesia.

Published record and description. Yamaguti (1953).

Published host records. Nemipteridae : Synagris sp. (5 Nemipterus sp. )

Site . Gills.

Distribution. Macassar, Celebes, Indonesia.

Remarks. The type material of B. synagris is of such poor quality that it has been of limited use in our analysis, but it is clear that this species can be distinguished from all Benedenia species by a combination of the following features: relatively large accessory sclerites (50±63 Mm) in relation to size of the haptor; broad anterior hamuli; gland cells between the pharynx and the anterior attachment organs; widely separated testes. Fresh material from the type-host from the type-locality is required to establish further details for this monogenean species. New material is likely to show whether the anterior attachment organs which, in the type material, are anterolaterally displaced and well set-oOE from the body, should be included in the list of distinguishing characters and should show whether the testes are widely separated even in unāttened material. Yamaguti (1953) described B. synagris as possessing separate male and uterine pores. If such a feature is veri®ed, it places B. synagris with B. sciaenae (and possibly B. pompatica ) although these species can be distinguished clearly from each other by size.