Macrourimegatrema brayi n. gen., n. sp. (Digenea: Opecoelidae) from four species of deep-sea macrourid fishes from the Gulf of Mexico and Caribbean Sea, with a list of endohelminths reported from species of Bathygadus and Gadomus (Macrouridae)

Abstract

Macrourimegatrema brayi n. gen., n. sp. (Digenea: Opecoelidae: Plagioporinae) is described from the pyloric ceca and intestines of 4 species of bathygadine macrourid fishes collected from deep waters of the Gulf of Mexico and off Colombia and Panama. Macrourimegatrema n. gen. can be distinguished from all other genera in the subfamily by possessing a combination of the following diagnostic characteristics: an atypically large elongate body; a short, distinct forebody separated from a long hindbody by a distinct constriction at the level of the acetabulum; a terminal, funnelshaped oral sucker; nearly equatorial ovary and testes and an unusual tubular excretory vesicle that winds between the 2 tandem testes. Macrourimegatrema n. gen. is most similar to the genus Anabathycreadium, but the former differs in having a smaller body size (6,000 vs 15,500 m); a funnelshaped oral sucker; a slightly protuberant acetabulum; suckers of equal size; an oval pharynx (rather than being ring-shaped); ceca that terminate some distance from the posterior extremity; a smaller cirrus sac that reaches only a short distance postacetabularly (rather than reaching to the level of the ovary); a genital pore that is bifurcal to slightly prebifurcal (rather than being at the posterior margin of the pharynx); numerous, small, follicular vitelline follicles that approach the level of the acetabulum anteriorly (rather than terminating well short of the level of the acetabulum); an ovary that is immediately pretesticular (rather than being far removed anteriorly from the anterior testis) and M. brayi n. gen., n. sp. has an unusual tubular excretory vesicle that winds between the 2 testes. Species of opecoelids are expected to utilize either a crustacean or fish second intermediate host, and the lack of fish reported for the food preferences of members of Bathygadinae studied here suggest that M. brayi n. gen., n. sp. probably infects its host through ingestion of a near-bottom pelagic crustacean. The precedence of using general body morphology of the species or its conformation to the characteristics of the 4 subfamilies of Opecoelidae is discussed.

Macrourimegatrema gadoma n. sp. (Digenea: Opecoelidae) from the doublethread grenadier Gadomus arcuatus (Goode & Bean) (Macrouridae) in the Gulf of Mexico and Caribbean Sea

“…We also observed this same feature in several specimens of M. brayi. While the current generic diagnosis of Macrourimegatrema is already unique (Blend et al, 2004) when compared to other opecoelid genera in the key to the Plagioporinae of Cribb (2005), we feel this feature may be of additional generic importance, since it was observed in both M. brayi and M. gadoma n. sp. It is also important to note that a few specimens identified as M. brayi (based on the extent and distribution of the vitellarium) were twice recovered from four specimens of Gadomus arcuatus (see Blend et al, 2004) in concurrent infections with M. gadoma n. sp.…”

“…While the current generic diagnosis of Macrourimegatrema is already unique (Blend et al, 2004) when compared to other opecoelid genera in the key to the Plagioporinae of Cribb (2005), we feel this feature may be of additional generic importance, since it was observed in both M. brayi and M. gadoma n. sp. It is also important to note that a few specimens identified as M. brayi (based on the extent and distribution of the vitellarium) were twice recovered from four specimens of Gadomus arcuatus (see Blend et al, 2004) in concurrent infections with M. gadoma n. sp. Because of the distinct differences, such as the extent and distribution of the vitelline fields, body size (Table 1) and position of the gonads relative to the entire worm as well as the small number of M. brayi found in G. arcuatus (intensity 1-2 worms) by Blend et al (2004), we believe the two to be different species.…”

“…It is also important to note that a few specimens identified as M. brayi (based on the extent and distribution of the vitellarium) were twice recovered from four specimens of Gadomus arcuatus (see Blend et al, 2004) in concurrent infections with M. gadoma n. sp. Because of the distinct differences, such as the extent and distribution of the vitelline fields, body size (Table 1) and position of the gonads relative to the entire worm as well as the small number of M. brayi found in G. arcuatus (intensity 1-2 worms) by Blend et al (2004), we believe the two to be different species. M. brayi appears to be a common parasite of species of Bathygadus and to occur only occasionally in species of Gadomus; this species also exhibits a broader host range occurring in at least four macrourid species.…”

“…The new species belongs to Macrourimegatrema within the Plagioporinae Manter, 1947 as defined by Blend et al (2004) and Cribb (2005). Macrourimegatrema gadoma n. sp.…”

Allopodocotyle tunisiensis sp. nov. (Digenea, Opecoelidae), a parasite of Solea aegyptiaca (Teleostei, Soleidae) off Tunisia

“…nov. fits into group C (sensu Bray 1987), with the testes tandem rather than oblique and a cirrus sac that extends into the hindbody. According to Blend et al (2004), there are nine species of Allopodocotyle in this group: A. pedicellata, A. atzi (Nigrelli, 1939), A. mecopera (Manter, 1940), A. argyropsi Madhavi, 1975, A. lutianusi Gupta et Ahamad, 1976, A. israelensis, A. jaffensis, A. recifensis Bray, 1987and A. margolisi Gibson, 1995. Among these species, A. margolisi fits into any of Bray's groups, but it is most similar to the worms in group C except that its cirrus-sac does not extend into the hindbody (Gibson 1995).…”