Potamanthellus
Guides
Neoephemeridae
large squaregill mayflies
Neoephemeridae is a small family of mayflies in the suborder Furcatergalia, containing approximately 13-17 described species across four genera: Neoephemera (Nearctic), Ochernova (Central Asia), Leucorhoenanthus (West Palearctic), and Potamanthellus (East Palearctic and Oriental). Nymphs are characterized by distinctive fimbriate (fringed) dorsal-oriented gills on abdominal segments, giving rise to the common name "large squaregill mayflies." The family has a disjunct Holarctic-Oriental distribution with recent findings in southwestern and northwestern China linking previously isolated genera biogeographically.