Question Mark

In recent years, environmental DNA (eDNA) analyses of freshwater environments by researchers have contributed to the rediscovery of species previously considered extinct. Here, researchers report on the "rediscovery" of the Jindai Dojo, an undescribed 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝𝑝. (Cobitidae), with mythical-like properties in folklore. 🔓 (In-press) -nature.com/articles/s41598-0… Long thought extinct, the authors' findings support the hypothesis that the Jindai Dojo is conspecific with 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I and indicate that this lineage persists within its historical range and nearby river basins. "Our study demonstrates the value of integrating species-specific eDNA assays with phylogeographic information to rediscover threatened lineages and clarify the taxonomic identities of organisms presumed to be extinct." The "mythical" status of the Jindai Dojo stems from a blend of localised folklore and historical anomalies. According to local historians, a severe epidemic swept through the region during the Edo period, local villagers believed that if sick people ate the unusually large loaches caught from the deep, mud-heavy local rice fields, they would miraculously recover from the illness. Believing the fish was a holy entity taking on human suffering, they began calling it the Shindai or Jindai Dojo - the loach where a God became a body substitute. 𝗥𝗲𝘀𝗲𝗮𝗿𝗰𝗵 𝗧𝗶𝘁𝗹𝗲 Environmental DNA supports persistence of the mythical Japanese freshwater fish “Jindai Dojo” and its conspecificity with an Eastern Japanese relict species 𝗖𝗶𝘁𝗮𝘁𝗶𝗼𝗻 Ito, G., Yashima, Y., Ohgita, S. et al. Environmental DNA supports persistence of the mythical Japanese freshwater fish “Jindai Dojo” and its conspecificity with an Eastern Japanese relict species. Sci Rep (2026). doi.org/10.1038/s41598-026-6… 𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁 Environmental DNA (eDNA) analysis provides a means of detecting cryptic and rare taxa and identifying their genetic lineages, even when they are no longer detected by conventional surveys. The freshwater dojo loach locally known as the “Jindai Dojo” was historically collected in Iga City, central Honshu, Japan, and morphological evidence has suggested that it is conspecific with 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I, a cryptic relic species distributed in eastern Japan that is of high conservation concern. However, the “Jindai Dojo” has long been considered extinct, and neither its proposed taxonomic identity nor its persistence has been evaluated using genetic evidence. Therefore, we integrated a 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I-specific eDNA assay with a phylogeographic framework and analyzed water samples collected from 33 sites in and around Iga City. 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I eDNA was detected at six sites, including three sites within the historical range of the “Jindai Dojo” and three sites in nearby river basins with no previous collection records. Sequence analysis of the amplified mitochondrial DNA fragments showed that all detections belonged to subclade J of the Japan Sea-side clade of 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I. These findings support the hypothesis that the “Jindai Dojo” is conspecific with 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I and indicate that this lineage persists within its historical range and nearby river basins. Our study demonstrates the value of integrating species-specific eDNA assays with phylogeographic information to rediscover threatened lineages and clarify the taxonomic identities of organisms presumed to be extinct. 𝗣𝗵𝗼𝘁𝗼 𝗖𝗿𝗲𝗱𝗶𝘁 Loaches of the genus 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 in the Japanese Archipelago. (a) Specimen of the “Jindai Dojo,” 119.1 mm SL (standard length) (MIE-Fi1512). (b) Specimen of 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑠𝑝. Type I, 92.7 mm SL (KUN-P59954). (c) Specimen of 𝑀𝑖𝑠𝑔𝑢𝑟𝑛𝑢𝑠 𝑎𝑛𝑔𝑢𝑖𝑙𝑙𝑖𝑐𝑎𝑢𝑑𝑎𝑡𝑢𝑠, 96.3 mm SL (KUNP59924). © 2026 the Author(s). Published in the journal Scientific Reports. An open access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. creativecommons.org/licenses… #RelictSpecies #eDNA #Ichthyology #EnvironmentalDNA #Biodiversity #AquariumHobby #Fishkeeping #Aquarist #TropicalFish #FishTank #Japan #JindaiDojo #Loach #Loaches #Conservation #FreshwaterConservation #Misgurnus #LostFishes #MythicalFishes #Cobitidae