Epeorus Eaton 1881
Creators: name: Takayanagi, Tatsushi
name: Yoshizawa, Kazunori
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Heptageniidae
Epeorus

description: Key to mature nymphs in Sapporo City and adjacent areas
1 Gill I anteriorly enlarged (Figs 16e, 17e, 24d, 25e); gill VII with longitudinal fold (Figs 17g, 25g); pronotum slightly projecting laterally (Figs 29b, d)................................................................................. 2
- Gill I not anteriorly enlarged (Figs 6d, 7e, 11d, 21d, 22e); gill VII without longitudinal fold (Figs 7h, 22g); pronotum roundly projecting laterally (Figs 29a, c)......................................................................... 3
2 Gill I strongly enlarged and meet at beneath mesothorax (Figs 15b, e, 16e, 17e); posterior margin of abdominal terga with sharp denticles (Figs 17j, 31c).................................................................. E. (C.) curvatulus
- Gill I slightly enlarged and not meet at beneath mesothorax (Figs 23b, e, 24d, 25e); posterior margin of abdominal terga with blunt denticles (Figs 25j, 31e)................................................................ E. (I.) aesculus
3 Gills with dark-violet spots (Figs 6d, 11d); gills II–VII with anal proximal projections (Figs 6d, 11d); posterior margin of abdominal terga with sharp denticles (Figs 7k, 12g, 31a, b).................................................... 4
- Gills without dark-violet spots (Fig. 21d); gills II–VII with anal ribs (Fig. 21d); posterior margin of abdominal terga with blunt denticles (Figs 22j, 31d).................................................................. E. (P.) nipponicus
4 Outer margin of inner incisor of the left mandible with sharp serration (Fig. 7c)....................... E. (B.) latifolium
- Outer margin of inner incisor of the left mandible without sharp serration (Figs 12c, f).................. E. (B.) L-nigrum
Key to male imagines in Sapporo City and adjacent areas
1 Black markings on the base of veins of the forewing (Figs 8e, 13e, 18e).......................................... 2
- No markings on the base of veins of the forewing (Fig. 26e)................................................... 3
2 Penis with titillators (Figs 13f, 18f)....................................................................... 4
- Penis without titillators (Fig. 8f)............................................................. E. (B.) latifolium
3 Forceps base without projection, penis laterally expanded with spines (Fig. 26f)........................ E. (I.) aesculus
- Forceps base with projection, penis laterally expanded without spines (following Ma et al. 2021: p. 1149, figs 12c, 13c).......................................................................................... E. (P.) nipponicus
4 Posterior margin of styliger plate triangular edged (Fig. 13f)....................................... E. (B.) L-nigrum
- Posterior margin of styliger plate rounded (Fig. 18f)............................................ E. (C.) curvatulus
description: Published as part of Takayanagi, Tatsushi & Yoshizawa, Kazunori, 2025, Taxonomic review of Epeorus s. l. Eaton, 1881 (Ephemeroptera: Heptageniidae) in Sapporo City and adjacent areas, Hokkaido, Japan, pp. 1-49 in Zootaxa 5594 (1) on pages 36-38, DOI: 10.11646/zootaxa.5594.1.1, http://zenodo.org/record/14953985