The morphological characters of the freshwater shrimp called “Ryugu-hime-ebi” in Japan are not always consistent with those of Caridina laoagensis, which has been given its Japanese name. Recently, a cryptic species of C. weberi species group that includes C. laoagensis was newly described as Caridina tupaia. We aimed to resolve the historical confusion between C. laoagensis and C. tupaia in Japan. For DNA barcoding and morphological examination, we recognized the two taxa in “Ryugu-hime-ebi,” i.e. C. laoagensis and C. tupaia. Based on some diagnostic characters, we reviewed previous records and found that the taxon that was given the Japanese name “Ryugu-hime-ebi” was most likely C. tupaia. We proposed to give the standard Japanese name “Ryugu-hime-ebi” to C. tupaia and the new standard Japanese name “Un-mon-hime-ebi” to C. laoagensis.
Figure: Caridina tupaia and C. laoagensis. Photo by the authors.
