Neocaridina

Establishment of the genus Neocaridina was established by I. Kubo in 1938 during taxonomic work on Japanese atyid shrimp, separating a set of freshwater taxa from related genera within Atyidae. The type species is Neocaridina denticulata (de Haan, 1844). A well-studied example is Taiwan, where COI sequence datasets have been used to identify multiple Neocaridina taxa on the island and infer several separate colonisation events from mainland East Asia and the Japanese islands. Nomenclatural notes (aquarium-traded taxa) Some aquarium-traded “Neocaridina” have been historically reported under different names (including treatments involving N. heteropoda and N. denticulata complexes), contributing to persistent confusion in non-specialist contexts; integrative taxonomy continues to refine species limits and synonymies within these complexes. == Description ==

General morphology Members of Neocaridina are small caridean shrimp. As in other Atyidae, they have specialised mouthparts and feeding appendages adapted to grazing on fine organic material and biofilms on submerged surfaces. Diagnostic characters used in atyid shrimp taxonomy commonly include features of the rostrum, antennular and antennal segments, pereiopods (including setation and proportions), and reproductive structures such as the male first pleopod and appendix masculina on the second pleopod. Life cycle strategy (land-locked freshwater habit) Neocaridina species are often described as “land-locked” freshwater shrimp, completing their full life cycle in freshwater rather than requiring a prolonged marine or brackish larval phase typical of some other caridean lineages. This life history trait is relevant to dispersal, population structure, and island biogeography within East Asia. == Distribution and habitat ==

Native range Neocaridina is distributed across East Asia, including (depending on species) eastern Russia, the Korean Peninsula, the main islands of Japan and the Ryukyus, Taiwan, continental China, and Vietnam. == Ecology ==

Feeding and ecosystem roles Atyid shrimp can be important benthic consumers in freshwater systems, grazing on periphyton/biofilms and processing fine organic matter, thereby influencing algal biomass, community composition, and nutrient cycling. While many ecosystem-function studies focus on other atyid taxa, these findings are broadly relevant to understanding the ecological role of atyid shrimp assemblages that include Neocaridina. Experimental and observational work has also examined potential ecological effects of N. davidi, including altered structure of freshwater meiofaunal assemblages in controlled systems, supporting the view that high-density populations can influence lower trophic levels. == Relationship with humans ==

Aquarium trade Neocaridina species—especially Neocaridina davidi—are widely kept as ornamental freshwater shrimp in home aquaria and are distributed internationally through the aquatic pet trade. The popularity of selectively bred colour morphs is a major driver of trade volume and repeated introductions into non-native regions via release or escape. Risk-screening and synthesis documents for the United States have assessed N. davidi as a nonindigenous species of concern and summarised evidence on establishment pathways, potential ecological effects, and the role of ornamental trade in introductions. == Species ==

The exact composition of Neocaridina varies by taxonomic treatment. A widely cited global catalogue of caridean shrimp provides a baseline species compilation for the genus, with multiple additional species described subsequently in regional revisions (e.g., Taiwan) and integrative studies. The following list largely follows De Grave & Fransen (2011) with later additions where explicitly sourced: • Neocaridina anhuiensis Liang, Zhu & Xiong, 1984 • Neocaridina bamana (Liang, 2004) • Neocaridina brevidactyla (Liang, Chen & W.-X. Li, 2005) • Neocaridina curvifrons Liang, 1979 • Neocaridina davidi (Bouvier, 1904) • Neocaridina denticulata (de Haan, 1844 • Neocaridina euspinosa Cai, 1996 • Neocaridina fonticulata Shih, Cai & Chiu, 2019 • Neocaridina fukiensis Liang & Yan, 1977 • Neocaridina gracilipoda (Liang, 2004) • Neocaridina hofendopoda Shen, 1948 • Neocaridina homospina (as treated in catalogues and subsequent literature) • Neocaridina iriomotensis Naruse, Shokita & Cai, 2006 • Neocaridina ishigakiensis Fujino & Shokita, 1975 • Neocaridina ketagalan Shih & Cai, 2007 • Neocaridina keunbaei H. S. Kim, 1976 • Neocaridina linfenensis Cai, 1996 • Neocaridina longipoda Cai, 1995 • Neocaridina palmata (Shen, 1948) • Neocaridina saccam Shih & Cai, 2007 • Neocaridina spinosa Liang, 1964 • Neocaridina xiapuensis Zheng, 2002 • Neocaridina yueluensis Chen, Chen & Guo, 2018 • Neocaridina zhangjiajiensis Cai, 1996 • Neocaridina zhoushanensis Cai, 1996 • Neocaridina kubo Shih & Cai, 2007 == References ==