Redescription of Metabronema magnum (Nematoda: Cystidicolidae), a swimbladder parasite of the carangid fish Gnathanodon speciosus off New Caledonia

Abstract

Abstract. The cystidicolid nematode Metabronema magnum (Taylor, 1925) is redescribed from specimens collected from the swimbladder of the fish (golden trevally) Gnathanodon speciosus (Forsskål) (Carangidae, Perciformes) off New Caledonia, South Pacific (a new geographical record). The light and scanning electron microscopical examination made it possible to study in detail the morphology of this so far little-known species. Its pseudolabia were found to possess distinct anterior protrusions (protuberances), sublabia are absent, only four cephalic papillae are present, deirids are bifurcated, and the male possesses six pairs of postanal papillae. By its morphology, M. magnum seems to be most similar to species of Salvelinema Trofimenko, 1962, also from the swimbladder of fishes, differing from them mainly in the presence of median wedge-shaped outgrowths in the mouth, lateral alae, the longer spicule on the right side, and a fewer number of pairs of preanal papillae in the male. Since the morphology of M. magnum considerably differs from that of other representatives of the Cystidicolidae, Metabronema in Rasheed's (1966) conception is considered a valid genus.

New data on the morphology of Comephoronema oschmarini (Nematoda, Cystidicolidae), a little-known gastrointestinal parasite of Lota lota (Teleostei) in Palaearctic Eurasia

“…The SEM examination of this species also revealed that the deirids of this species are bifurcated (Fig. 3D); the shape of deirids has recently been found to be an important taxonomic feature in cystidicolids (e.g., MuZoz et al 2004, Ferrer et al 2005, Moravec et al 2006, Moravec and Justine 2007, Moravec and Klimpel 2007.…”

“…Trofimenko (1974) reported eight cephalic papillae arranged in two circles in C. oschmarini, but the SEM examination did not confirm the presence of the four small papillae of the internal circle (Fig. 3A-C); only four cephalic papillae as in C. oschmarini are also reported for other cystidicolid species studied by SEM (e.g., Moravec and Nagasawa 1999, Frantová and Moravec 2003, Ferrer et al 2005, Moravec and Justine 2007, Moravec and Klimpel 2007. In the SEM micrograph of C. oschmarini from Russia recently sent to the senior author (F.M.)…”

Pseudascarophis brasiliensis sp. nov. (Nematoda: Cystidicolidae) parasitic in the Bermuda chub Kyphosus sectatrix (Perciformes: Kyphosidae) from southeastern Brazil

“…Moreover, there exist various intermediate features that can be interpreted as interspecific rather than intergeneric differences (Moravec & Klimpel 2007). Indeed, many members of these genera have been reported within Ascarophis (Ferrer et al 2005) or transferred to it (Moravec 2007, Moravec & González-Solís 2007, Moravec & Justine 2007 ). In fact, the latter authors have stated that it is apparent from SEM studies that the shape and size of pseudolabia, the shape of the mouth and the development of submedian labia (from well-developed to absent) may differ among Ascarophis species .…”

A new species of Ascarophis (Nematoda, Cystidicolidae) from the stomach of the marine scorpaeniform fish Hoplichthys citrinus from a seamount off the Chesterfield Islands, New Caledonia

“…Taking into account Ko's (1986) (Szidat, 1961) and S. nasonis (Machida, 1981). However, Moravec and González-Solís (2007) followed the conception of Ferrer et al (2005) and they synonymized Similascarophis with Ascarophis, reporting that the relationships among the species assigned to Ascarophis can only be resolved when substantial SEM data on the cephalic structures and molecular data accumulate (see also Moravec and Justine 2007, Moravec and Klimpel 2007.…”

“…Taking into account different host orders (Perciformes vs. Scorpaeniformes) and different geographical regions (Chile vs. New Caledonia), we consider nematodes of the present material to represent a new species. After Metabronema magnum (Taylor, 1925) (see Moravec and Justine 2007), Ascarophis richeri is the second cystidicolid nematode recorded from New Caledonian waters. It is the second fish parasite recorded from the region of the Chesterfield Islands, after an isopod (Trilles and Justine 2006).…”