Mesocyclops pehpeiensis Hu, 1943 is a Central-East Asian species, rarely found outside of this area, and when it appears should be considered as alien. Based on morphology and DNA barcode analyses, using the COI gene, the presence of M. pehpeiensis has been confirmed in a rice paddy near Valencia, Spain. DNA barcoding can be a fast and useful analytical tool to accurately identify alien species across the world.
More information here: Montoliu L., Miracle M.R., & Elias-Gutierrez M., 2015. Using DNA barcodes to detect non-indigenous species: the case of the Asian copepod Mesocyclops pehpeiensis Hu, 1943 (Cyclopidae) in two regions of the world. Crustaceana 88 (12-14): 1323-1338. DOI: 10.1163/15685403-00003500