REPORT ON TWO SPECIES OF DIGENEA FROM MARINE FISHES IN BRAZIL

Two species of Digenea were recorded for the first time in South America and in new hosts: Acanthostomum spiniceps (Looss, 1896) (Cryptogonimidae) was reported from Astroscopus sexspinosus (Steindachner, 1877) (Uranoscopidae) and Diplomonorchis sphaerovarium Nahhas & Cable, 1964 (Monorchiidae) from Ophichthus gomesi (Castelnau, 1855) (Ophichthidae). From the latter, Heliconema heliconema Travassos, 1919 (Nematoda, Physalopteridae), was also recovered representing also a new host for this nematode species.


INTRODUCTION
During the course of a study on fish parasites from the coast of Rio de Janeiro State, two species of Digenea, Acanthostomum spiniceps and Diplomonorchis sphaerovarium, and a species of nematode, Heliconema heliconema, were recovered from new hosts.These digenean species are reported for the first time in South America.

MATERIALS AND METHODS
The helminths were recovered from fishes from Copacabana and Urca beaches, Rio de Janeiro State, Brazil, and were fixed under coverslip pressure in AFA (alcohol, formalin, acetic acid), stained in alcoholic chlorydric carmine of Langeron, dehydrated in ethyl alcohol, cleared in beechwood creosote and mounted in Canada balsam.The illustrations were made with the aid of a Leitz drawing tube, and the measurements are in micrometers unless otherwise indicated.Material was deposited in the "Coleção Helmintológica do Instituto Oswaldo Cruz (CHIOC)".Considering that these helminths are well described, we present herein only the main measurements and figures of the two digenean species studied.
Intensity of infection: 1 out of the 10 fish specimens examined was parasitized by 1 Digenea.
Voucher specimens deposited: CHIOC n. 34.555.Measurements based on one specimen.Body 3.37 x 0.57 mm; oral sucker 318 x 270, surrounded by 27 spines in a row; pre-pharynx 67 long; pharynx 138 x 135; oesophagus 30; ventral sucker 150 x 138; sucker width ratio 1:0.5; anterior testis 285 in diameter and posterior testis 315 x 281; ovary 243 x 187; eggs 35-42 x 18.Up to the present moment, the genus Acanthostomum has been referred to only in freshwater fishes and reptiles.This is the first report of a member belonging to this genus in a marine fish.
The present study was based on a single specimen, which is closely related to those studied by Fischthal & Kuntz (1963) regarding to the body size, although presenting larger eggs.In relation to the number of circumoral spines, our specimen is similar to the material studied by Moravec (1976), with 27 spines.
Intensity of infection: 4 out of the 21 fish specimens examined were parasitized by 1 to 4 Digenea.
Voucher specimens deposited: CHIOC n.Up to this date, the genus Diplomonorchis Hopkins, 1941, was represented in Brazil by three species: D. catarinensis from the intestine and pyloric caeca of Micropogonias furnieri (Sciaenidae) (Amato, 1982), D. floridensis Nahhas & Powell, 1965 from the intestine of Symphorus sp.(Cynoglossidae) (Wallet & Kohn, 1987) and D. leiostomi Hopkins, 1941 from the intestine of Haemulon sciurus (Pomadasyidae) (Kohn et al., 1982) and Boridia grossidens (Sparidae) (Fernandes et al., 1985).Diplomonorchis sphaerovarium was decribed from the intestine of Spheroides testudineus (Tetraodontidae) from Jamaica, and this is the first report of this species since its original description, representing also the first report of this species in South America and in a new host.The specimens presently studied are similar to those reported in the original description, being slightly longer.

Heliconema heliconema Travassos, 1919
Adult and larval forms of H. heliconema were also recovered from two out of the 21 specimens of O. gomesi examined.From Brazil this species was originally described by Travassos (1919) from Echidina catenata (Muraenidae) from Trindade Island, and has been reported by Guimarães et al. (1976) from Ophichthus ophis (Ophichthidae) from Bahia State.It was also reported from Pakistan by Khan & Begum (1971) parasitizing Muraenesox cinereus (Muraenesocidae).The present data on H. heliconema are in agreement with those previously stated and no additional comments are required, except for the new host record, Ophichthus gomesi.