Jorge F, White R S A, Paterson R A
Department of Zoology,University of Otago,PO Box 56,Dunedin 9054,New Zealand.
School of Biological Sciences,University of Canterbury,Private Bag 4800,Christchurch 8140,New Zealand.
J Helminthol. 2018 May;92(3):379-386. doi: 10.1017/S0022149X17000530. Epub 2017 Jun 22.
The extent of New Zealand's freshwater fish-parasite diversity has yet to be fully revealed, with host-parasite relationships still to be described from nearly half the known fish community. While advances in the number of fish species examined and parasite taxa described are being made, some parasite groups, such as nematodes, remain poorly understood. In the present study we combined morphological and molecular analyses to characterize a capillariid nematode found infecting the swim bladder of the brown mudfish Neochanna apoda, an endemic New Zealand fish from peat-swamp-forests. Morphologically, the studied nematodes are distinct from other Capillariinae taxa by the features of the male posterior end, namely the shape of the bursa lobes, and shape of spicule distal end. Male specimens were classified into three different types according to differences in the shape of the bursa lobes at the posterior end, but only one was successfully characterized molecularly. Molecular analysis indicated that the studied capillariid is distinct from other genera. However, inferences about the phylogenetic position of the capillariid reported here will remain uncertain, due to the limited number of Capillariinae taxa characterized molecularly. The discovery of this new capillariid, which atypically infects the swim bladder of its host, which itself inhabits a very unique ecosystem, underlines the very interesting evolutionary history of this parasite, which for now will remain unresolved.
新西兰淡水鱼寄生虫的多样性程度尚未完全揭示，近一半已知鱼类群落的宿主-寄生虫关系仍有待描述。虽然在已检测的鱼类物种数量和已描述的寄生虫分类群方面取得了进展，但一些寄生虫类群，如线虫，仍了解甚少。在本研究中，我们结合形态学和分子分析，对一种毛细线虫进行了特征描述，该线虫感染了新西兰特有的泥炭沼泽森林中的褐泥鱼（Neochanna apoda）的鳔。从形态学上看，所研究的线虫在雄性后端特征方面，即囊叶形状和交合刺远端形状，与其他毛细线虫属分类群不同。根据后端囊叶形状的差异，雄性标本被分为三种不同类型，但只有一种成功进行了分子特征描述。分子分析表明，所研究的毛细线虫与其他属不同。然而，由于分子特征描述的毛细线虫属分类群数量有限，此处报道的毛细线虫的系统发育位置推断仍不确定。这种新的毛细线虫非典型地感染其宿主的鳔，而宿主本身栖息在一个非常独特的生态系统中，这一发现突显了这种寄生虫非常有趣的进化历史，目前这一历史仍未得到解决。
