Two new Bucephalidae (Trematoda) from Fishes of the Brazilian Amazon

Two new species of Bucephalidae (Trematoda) are described from fishes of the Brazilian Amazon. Glandulorhynchus turgidus gen. et sp. n. from Hydrolycus sp. differs from all others in the family by having conspicuous glands near the anterior extremity and an expanded uterus used for storing eggs. Prosorhynchus piranhus sp. n. from Serrasalmus rhombeus is characterized as having a small rhynchus and pharynx, and a large cirrus sac.

Cleaner fish become hosts: a novel form of parasite transmission

Adult bucephalid trematodes (Digenea) generally only occur in piscivorous fish. Within labrid fishes they are very rare, however, we have found them in labrid cleaner fish that feed on the ectoparasites of fish. We surveyed 969 labrid fishes from the tropical Pacific and found bucephalids only in cleaners (Lahroides dimidiatus, L. bicolor, and Bodianus axillaris) and none in piscivores. The prevalences of bucephalids in L. dimidiatus at Lizard Island, Heron Island, Orpheus Island (all on the Great Barrier Reef), New Caledonia, and Moorea (French Polynesia) were 51, 47, 67, 56, and 67%, respectively. All of the L. bicolor examined from Moorea were infected. Bucephalids were highly prevalent in all size classes of L. dimidiatus from Lizard Island. Bucephalids were found in a 1.6-cm long juvenile L. dimidiatus, in which, piscivory is highly unlikely. We examined the literature on the worldwide bucephalid fauna in labrids and all hosts were found to be cleaners (Symphodus tinca, S. mediterraneus, L. dimidiatus, L. bicolor, and Bodianus axillaris) except Notolabrus parilus, whose ecology is unknown. We suggest that cleaners eat bucephalid metacercariae directly from the exterior surface of client fish during cleaning interactions. This is the first evidence of digeneans in the diet of L. dimidiatus, and the first study to show this novel form of parasite transmission where infective stages are eaten as a result of cleaning behaviour. Cleaning-mediated parasite transmission may result in behavioural modification of second intermediate hosts because clients and parasites both benefit from transmission. If the infection is costly to cleaners and acquired during cheating behaviour, then this parasite might regulate mutualism. Alternatively, if infective stages are targeted, infection by these bucephalids may be a negative consequence of an honest foraging strategy.

Prosorhynchoides lamprelli n. sp (Digenea : Bucephalidae) from the brassy trevally, Caranx papuensis (Teleostei : Carangidae), from off Lizard Island on the Great Barrier Reef, Australia

Prosorhynchoides lamprelli n. sp. ( Digenea: Bucephalidae) is described from the intestine of the brassy trevally, Caranx papuensis (Carangidae) from off Lizard Island, Great Barrier Reef, Australia. The new species is differentiated from other species of Prosorhynchoides Dollfus, 1929 by the shape and distribution of its vitelline follicles, the shape and extent of its uterus and the configuration of its digestive system. This is the first bucephalid to be described from Caranx papuensis; we have not encountered this species from other carangids or from over 1,500 individuals of other teleosts species we have found to be infected with bucephalids from the Great Barrier Reef.

Grammatorcynicola n. g. (Bucephalidae : Dolichoenterinae) from Grammatorcynus spp. (Scombridae) on the Great Barrier Reef, Australia

A new trematode genus, Grammatorcynicola n. g. (Bucephalidae: Dolichoenterinae), and two new species, G. brayi n. sp. and G. nolani n. sp. from the intestines of the scombrids, Grammatorcynus bicarinatus and Gr. bilineatus respectively, are reported from the Great Barrier Reef, Australia. Grammatorcynicola n. g. is placed in the Dolichoenterinae, as the pharynx is in the anterior quarter of the body, the caecum is tube-like and extends to the posterior quarter of the body, the cirrus-sac is small relative to the size of the worm when compared with other bucephalids and the pars prostatica is curved. Grammatorcynicola n. g. differs from other dolichoenterine genera in having a simple sucker-like rhynchus, the ovary anterior to the testes and by not having a particularly thick cirrus-sac wall.

Patterns of digenean parasitism of bivalves from the Great Barrier Reef and associated waters

Digenean parasites of marine bivalves are relatively poorly known, particularly in Australia. We surveyed 2256 bivalve individuals ( 47 species, 17 families) from Queensland marine waters incorporating south-east Queensland, Heron Island ( southern Great Barrier Reef) and Lizard Island ( northern Great Barrier Reef). Infections of trematode species from three families, Bucephalidae, Gorgoderidae and Monorchiidae, were found. Overall prevalence of infection was 2.3%. The Bucephalidae was the most commonly found family; 11 species were found in Tellinidae, Ostreidae, Isognomonidae and Spondylidae - the latter two previously unknown as hosts for bucephalids. A single gorgoderid infection was found in a venerid, Lioconcha castrensis. Five species of monorchiids were found from Tellinidae and Lucinidae. All infections are new host/parasite records. No infections were found in 35 of the 47 bivalve species sampled. The generally low prevalence of infection by digeneans of bivalves suggests that it is unlikely that any of the species reported here are seriously damaging to bivalve populations in these waters. We deduce that, at best, we have some life-cycle information but no actual identifications for 10% of the species of trematodes that infect bivalves of Queensland marine waters.