Rhoenanthus (Potamanthindus), 1930

Han, Na, Zhang, Min & Zhou, Chang-Fa, 2021, The genus Rhoenanthus Eaton, 1881 in China with the redescription of R hunanensis You & Gui, 1995 (Ephemeroptera: Potamanthidae), Zootaxa 4903 (4), pp. 563-577 : 575

Key to species of subgenus Rhoenanthus (Potamanthindus) : mature nymph

1. Spines on mandibular tusks base, lateral margins and dorsal surface ( Fig. 10A, 10D )............................... 2

- Spines on mandibular tusks base only, other parts of tusks reddish to dark brown, smooth ( Figs 2A , 10G )............... 4

2. Whole dorsal surface of mandibular tusks with numerous short spines ( Fig. 10A )............................. R. sapa

- Apical half or more of tusks with limited number of larger spines............................................... 3

3. Spines on mandibular tusk progressively shorter, without subapical large spine ( Fig. 10D )...................... R. youi

- Large subapical spine present, making mandibular tusk nearly forked.................................. R. coreanus

4. Apical brown part of mandibular tusk bent inward abruptly ( Fig. 10G ).................................. R. obscurus

- Apical brown part of mandibular tusk bent smoothly or near straight ( Fig. 2A ).................................... 5

5. Brown part of mandibular tusk near straight, relatively longer and slender ( Fig. 2A )..................... R. hunanensis

- Brown part of mandibular tusk bent inward smoothly, relatively shorter and broader...................... R. magnificus

Figures

FIGURE 2. Nymphal characters of Rhoenanthus hunanensis (digital photos).A. Habitus in dorsal view; B. Head and pronotum of another more mature nymph (dorsal view, showing mandibular tusks); C. Enlarged section of the antenna.

FIGURE 10. Selected structures of Rhoenanthus spp. (digital photos). A–C. R. sapa; D–F. R. youi; G–I. R. obscurus: A, D, G. Anterior part of body (showing the relatively length of mandibular tusks, forelegs and their setae); B, E, H. Maxilla (dorsal view); C, F, I. Labrum (ventral view).