Gyrodactylus nigeri n. sp. (Monogenea: Gyrodactylidae) parasitic on Yunnanilus niger (Cypriniformes: Nemacheilidae) from Yunnan Province, Southwest China

Abstract

To investigate the infection of fish of the genus Yunnanilus by Gyrodactylus (Monogenea) parasites in the karst region of Yunnan (Southwest China), Gyrodactylus individuals were obtained from the rare and vulnerable host black loach Yunnanilus niger. Based on morphology and partial internal transcribed spacer (ITS) sequence data, we identified and described a new species Gyrodactylus nigeri n. sp. Obtained from the fins of Y. niger from Yunnan Province, Southwest China. Of all available gyrodactylid sequences, the ITS fragment obtained has the highest similarity (88.3%) to the same part of the rDNA of Gyrodactylus kobayashii. The prevalence and mean intensity were 100% and 11.9, respectively. The morphological comparison of the similar haptoral structures revealed slight differences between the new species and the five Gyrodactylus species found in the hosts of Nemacheilidae, and the marginal hooks were compared with the 18 Gyrodactylus species found in the hosts of Nemacheilidae. In particular, G. nigeri n. sp. has robust, long, and straight hamuli with inclined roots, the lingulate ventral bar membrane, a short marginal sickle with a blunt marginal hook toe of marginal hooks, and an oval male copulatory organ (MCO). Gyrodactylus nigeri n. sp. is the first Gyrodactylus species isolated from Y. niger. Furthermore, phylogenetic analyses showed that the new species is a new member of the subgenus G. (Limnonephrotus).

Keywords

• Gyrodactylus nigeri n. sp.
• Yunnanilus niger
• Southwest China
• Morphology
• Phylogenetic analysis