Neoephemera

Distinguished from other Neoephemeridae genera by the combination of: nymphs with dorsal-oriented fimbriate gills and caudal filaments lacking swimming setae; adults with large reddishly pigmented wings, unforked anal vein, and 4-segmented forceps with elongated basal segment. N. projecta was distinguished by its exceptional size and primitive character states including fused penes and many wing crossveins.

Nymphs inhabit lotic freshwater environments, specifically creeks. Specific microhabitat preferences within streams are not documented.

North America (species: N. bicolor, N. compressa, N. maxima, N. purpurea, N. youngi) and Asia (N. projecta in southwestern China: Yunnan, Sichuan, and Shaanxi provinces). One extinct species, N. antiqua, known from the Ypresian Klondike Mountain Formation (51–49 million years ago) in northeast Central Washington State, USA.

Adults have been observed in April in southwestern China. Activity occurs in the afternoon.

Hemimetabolous with aquatic nymphal and terrestrial adult stages. Nymphs collected in April in China; adults (subimagoes and imagoes) emerge in afternoon. Eggs are long-oval with finger-like projections on the surface. No further details on egg development, nymphal instars, or emergence triggers documented.

Adults are active in the afternoon near creeks. Subimagoes and imagoes have been observed in April. Tarsal segments of subimagoes bear only microtrichia.

Of interest to mayfly systematists due to phylogenetic position linking other Neoephemeridae genera. The extinct species N. antiqua contributes to understanding of Eocene aquatic insect faunas in North America.

• PulchephemeraFormerly included N. projecta, distinguished by larger size, more plesiomorphic characters (fused penes, many crossveins), and geographic isolation in southwestern China.
• PotamanthidaePreviously considered related to Neoephemera, but N. projecta characters show closer affinity to Fossoriae clade rather than Potamanthidae.

• Ephemeroptera
• Neoephemeridae
• mayflies
• aquatic insects
• palearctic
• nearctic
• fossil taxon

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• The Imaginal Characters of Neoephemera projecta Showing Its Plesiomorphic Position and a New Genus Status in the Family (Ephemeroptera: Neoephemeridae)