D3491: Revealing cryptic species of Korean mayfly genus Baetis Leach (Ephemeroptera: Baetidae)

Woo Seong Kim1, Jeong Mi Hwang2, Ji Hyoun Kang2, Changseob Lim3 and Yeon Jae Bae1,2

1Department of Environmental Science and Ecological Engineering, Graduate School, Korea university, Seoul 02841, Republic of Korea
2Korean Entomological Institute, Korea University, Seoul 02841, Republic of Korea
3Ojeong Resilience Institute, Korea University, Seoul 02841, Republic of Korea

The family Baetidae is considered to be a basal lineage of living mayflies and is the most diverse family within the order Ephemeroptera. Its genus Baetis Leach encompasses over 150 species and can be found in various freshwater habitats. While more than 40 Baetis species have been documented in the Northeast Asian region, including Korea, Japan, Mongolia, and the Russian Far East, only four species from the genus have been identified in Korea: Baetis fuscatus (Linnaeus), B. silvaticus Kluge, B. pseudothermicus Kluge, and B. ursinus Kazlauskas. In this study, we obtained DNA barcode sequences of the COI gene for Korean Baetis species using a comprehensive collection of museum-stored and fresh larval and adult materials. The aim was to uncover potential cryptic diversity within the genus. Additionally, we examined the larval morphology to identify and associate the molecular operational taxonomic units (MOTUs) from the constructed phylogenetic trees with both known and undescribed species within the genus. Notably, a significant intraspecific p-distance of approximately ~21% was observed within the B. silvaticus and B. fuscatus clades. Further discussion on the cryptic diversity of Korean Baetis was presented, with emphasis on the genetic distances as criteria for delineating the Korean Baetis taxa.