Epibiont Cohabitation in Freshwater Shrimp Neocaridina davidi with the Description of Two Species New to Science, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., and Redescription of Scutariella japonica and Holtodrilus truncatus †

SIMPLE SUMMARY: Examination of epibiont distribution in Neocaridina davidi shrimp revealed occurrence of two species new to science. The number of epibionts differed between the four designated microhabitats on the host body, as well as between wild, aquaculture, and aquarium shrimp, most likely reflecting their preferences. Some epibiotic species may adversely affect the host, while others can be used to control others. Thus, the ability to identify them, as well as knowledge of their preferences and impact on the host and each other, may prove useful in controlling their spread and limiting accidental co-introductions as potentially invasive alien species. ABSTRACT: This contribution presents the occurrence of epibiotic species associated with Neocaridina davidi shrimp collected in the wild, aquaculture ponds, and aquaria. A total of 900 shrimp are imported from Taiwan, three-quarters of which host at least one of the recorded epibionts. Among those epibionts, two species new to science are discovered, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., while the other two, Holtodrilus truncatus and Scutariella japonica, are redescribed. The largest number of epibionts is found in shrimp collected from aquaculture ponds and the lowest in individuals from aquaria. Epibiont occurrence differs across designated microhabitats. The epibionts may be introduced alongside their host outside their native range, and their presence may affect shrimp breeding rates. Thus, more control over them should be provided. Their spread can be limited by removal from the host during molting or manually, as well as by using interspecies interactions.