Recent examinations of newly obtained materials of dracunculoid nematodes (Dracunculoidea) parasitizing marine fishes off New Caledonia, South Pacific, revealed the presence of several nematodes of the genera Philometra Costa, 1845 (Philometridae) and Ichthyofilaria Yamaguti, 1935 (Guyanemidae), including the following four new species: Philometra priacanthi sp. n. (males) from the gonads of Priacanthus hamrur (Forsskål) (Priacanthidae), Philometra tenuicauda sp. n. (male and mature and gravid females) from the gonads of Lagocephalus sceleratus (Gmelin) (Tetraodontidae), Philometra dentigubernaculata sp. n. (males) from the oculo-orbit of Tylosurus crocodilus (Péron et Lesueur) (Belonidae), and Ichthyofilaria novaecaledoniensis sp. n. (subgravid female) from the musculature of Hoplichthys citrinus Gilbert (Hoplichthyidae). The new species are characterized mainly by the length and structure of spicules and the gubernaculum, body size, location in the host and by the type of hosts. In addition, the findings of Philometra lethrini Moravec et Justine, 2008 from the gonads of Lethrinus miniatus (Forster) and L. variegatus Valenciennes (both Lethrinidae) represent new host records for this parasite; for the first time, its subgravid females were found to be up to 350 mm long. The occurrence of Philometra ocularis Moravec, Ogawa, Suzuki, Miyazaki et Donai, 2002 in the oculo-orbit of Epinephelus areolatus (Forsskål) (Serranidae) off New Caledonia was confirmed.
Numerous specimens of Calydiscoides spp. from Lethrinus nebulosus and L. harak, and fewer specimens from L. lentjan, L. ravus and L. obsoletus, collected off New Caledonia, South Pacific, were examined. Three species of Calydiscoides were recognized. Calydiscoides difficilis (Yamaguti, 1953) Young, 1969 was generally the most abundant species on the five hosts. Specimens of C. difficilis were measured and compared to the type specimens (from Indonesia) and museum vouchers (from Australia and the Arabian Gulf). The morphology of the massive male copulatory organ and of haptoral sclerotized parts was similar, but specimens from the same host and from different hosts showed wide morphometric variations; it is concluded that C. difficilis has a high degree of variability, although the possibility of a species complex remains. Calydiscoides duplicostatus (Yamaguti, 1953) Young, 1969 was found on L. nebulosus, L. harak and L. lentjan; specimens were homogeneous in the three hosts and similar to the type specimens. Calydiscoides terpsichore sp. n. is described from L. nebulosus (type host) and L. harak and was uncommon in both fish. The new species, a member of the 'australis group', is characterized by its Y-shaped male copulatory organ, with the left branch bearing a trifurcated secondary branch. Lethrinus nebulosus and L. harak shared the 3 species of Calydiscoides studied here, a fact probably related with their close phylogenetic relationships. Among the 15 species of Lethrinus present in New Caledonia, 11 were examined and 9 species harboured 1-3 species of Calydiscoides each. Only 7 species of Calydiscoides were found, due to their stenoxenous specificity. Each species of Calydiscoides has 1 to 5 hosts.