Santos Cláudia Portes, Gibson David I
Departamento de Biologia, Fundação Oswaldo Cruz, Av, Brasil, 4365, Rio de Janeiro, RJ, Brazil.
Syst Parasitol. 2007 Jul;67(3):225-34. doi: 10.1007/s11230-006-9080-4. Epub 2007 Apr 11.
Data-base searches of records of the helminth parasites of South American and African freshwater fishes revealed only two pairs of species from genera endemic to the two regions. One pair, species of the primitive amphilinid cestode genus Nesolecithus Dönges & Harder, 1966, has already been designated as likely Gondwana relicts. The second pair are the philometrid nematodes Nilonema gymnarchi Khalil, 1960 from Gymnarchus niloticus Cuvier (Gymnarchidae) in Africa and N. senticosum (Baylis, 1922) from the South American fish Arapaima gigas (Cuvier) (Arapaimidae). Both species are partly redescribed on the basis of light and scanning electron microscopical observations of the type-specimens, and their relationships are discussed. In view of the fact that both hosts are basal teleosts of the order Osteoglossiformes and they are the same two fish which harbour the amphilinid cestodes already indicated as Gondwana relics, the nematode pair is also deemed to be relictual. However, these species are suggested as being of limited potential value for calibrating a molecular clock.
对南美和非洲淡水鱼蠕虫寄生虫记录的数据库搜索显示，这两个地区特有的属中只有两对物种。其中一对是原始的双叶槽绦虫属Nesolecithus Dönges & Harder, 1966的物种，已被指定为可能的冈瓦纳遗迹。第二对是嗜子宫线虫，非洲的尼罗裸臀鱼（Gymnarchus niloticus Cuvier，裸臀鱼科）体内的Nilonema gymnarchi Khalil, 1960，以及南美巨骨舌鱼（Arapaima gigas (Cuvier)，骨舌鱼科）体内的N. senticosum (Baylis, 1922)。根据对模式标本的光学和扫描电子显微镜观察，对这两个物种进行了部分重新描述，并讨论了它们之间的关系。鉴于这两种宿主都是骨舌鱼目的基干硬骨鱼，而且它们也是携带已被指明为冈瓦纳遗迹的双叶槽绦虫的同两种鱼，所以这对线虫也被认为是遗迹物种。然而，这些物种被认为在校准分子钟方面的潜在价值有限。
