Reply to Fuke (2024): Clarifying the Taxonomic and Biogeographic Interpretations of Neocaridina in Japan

The taxonomy and biogeography of Neocaridina species in Japan remain complex and contested. In a recent commentary, Fuke (2024) criticized the conclusions of Shih et al. (2024), challenging their species delineations and argues that such taxonomy directly conditions interpretations of native versus introduced lineages. As the first two authors of Shih et al. (2024), we agree that accurate identification is essential for conservation of native taxa, but we contend that several of Fuke's inferences reflect misreadings of both morphological and genetic data. In this reply, we address these misinterpretations, clarify our taxonomic conclusions, and reassess phylogenetic and population genetic evidence. Our findings suggest that N. denticulata and N. davidi can be consistently distinguished using integrated molecular and morphological criteria, in contrast to Fuke's claim of conspecificity. We also emphasize the limitations of relying solely on mitochondrial DNA or SNP admixture patterns for species delimitation, particularly in hybridizing lineages. Finally, we advocate for integrative, evidence-based taxonomy as the best approach to resolving species boundaries and supporting conservation of cryptic native species of Neocaridina.