Smit Nico J, Bruce Niel L, Hadfield Kerry A
Water Research Group (Ecology), Unit for Environmental Sciences and Management, North West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520, South Africa.
Water Research Group (Ecology), Unit for Environmental Sciences and Management, North West University, Potchefstroom Campus, Private Bag X6001, Potchefstroom 2520, South Africa ; Museum of Tropical Queensland, Queensland Museum and School of Marine and Tropical Biology, James Cook University, 70-102 Flinders Street, Townsville 4810, Australia.
Int J Parasitol Parasites Wildl. 2014 Apr 13;3(2):188-97. doi: 10.1016/j.ijppaw.2014.03.004. eCollection 2014 Aug.
Of the 95 known families of Isopoda only a few are parasitic namely, Bopyridae, Cryptoniscidae, Cymothoidae, Dajidae, Entoniscidae, Gnathiidae and Tridentellidae. Representatives from the family Cymothoidae are obligate parasites of both marine and freshwater fishes and there are currently 40 recognised cymothoid genera worldwide. These isopods are large (>6 mm) parasites, thus easy to observe and collect, yet many aspects of their biodiversity and biology are still unknown. They are widely distributed around the world and occur in many different habitats, but mostly in shallow waters in tropical or subtropical areas. A number of adaptations to an obligatory parasitic existence have been observed, such as the body shape, which is influenced by the attachment site on the host. Cymothoids generally have a long, slender body tapering towards the ends and the efficient contour of the body offers minimum resistance to the water flow and can withstand the forces of this particular habitat. Other adaptations to this lifestyle include small sensory antennae and eyes; a very heavily thickened and calcified cuticle for protection; and sharply curved hooks on the ends of the pereopods which allows these parasites to attach to the host. Most cymothoids are highly site and host specific. Some of these parasitic cymothoids have been reported to parasitise the same host fish species for over 100 years, showing this species specificity. The site of attachment on the host (gills, mouth, external surfaces or inside the host flesh) can also be genus or species specific. This paper aims to provide a summary of our current knowledge of cymothoid biodiversity and will highlight their history of discovery, morphology, relationships and classification, taxonomic diversity and ecology.
在已知的95个等足目家族中，只有少数是寄生性的，即鳃虱科、隐虱科、缩头水虱科、巨颚虱科、内虱科、颚虱科和三叉虱科。缩头水虱科的代表是海洋和淡水鱼类的专性寄生虫，目前全世界有40个公认的缩头水虱属。这些等足类动物是大型（>6毫米）寄生虫，因此易于观察和采集，但它们生物多样性和生物学的许多方面仍然未知。它们广泛分布于世界各地，出现在许多不同的栖息地，但大多分布在热带或亚热带地区的浅水区。人们已经观察到许多适应 obligatory parasitic existence 的特征，比如身体形状，它受宿主附着部位的影响。缩头水虱通常身体细长，两端逐渐变细，身体的高效轮廓对水流的阻力最小，能够承受这个特定栖息地的力量。对这种生活方式的其他适应包括小的感觉触角和眼睛；非常厚且钙化的角质层用于保护；以及步足末端尖锐弯曲的钩子，使这些寄生虫能够附着在宿主身上。大多数缩头水虱具有高度的寄生部位和宿主特异性。据报道，其中一些寄生性缩头水虱已经寄生在同一宿主鱼类物种上超过100年，显示出这种物种特异性。在宿主上的附着部位（鳃、口、体表或宿主体内）也可能具有属或种的特异性。本文旨在总结我们目前对缩头水虱生物多样性的认识，并将重点介绍它们的发现历史、形态学、关系和分类、分类多样性和生态学。 （注：“obligatory parasitic existence”这里可能有拼写错误，推测正确表述可能是“obligate parasitic existence”，即专性寄生生活）
