Notacanthurus

Zhang, Wei, Zhang, Min, Han, Na & Zhou, Chang-Fa, 2020, Two new species of the genus Notacanthurus from China (Ephemeroptera: Heptageniidae, Ecdyonurinae), Zootaxa 4802 (2), pp. 335-348 : 345

Key to the known species of the genus Notacanthurus (mature nymph)

1. Median ridges on abdominal terga I–IX relatively small, without obvious posterior spines............................ 2

- Median ridges on abdominal terga I–IX large, forming clear posterior spines...................................... 3

2. Superlinguae with row of hair-like setae along outer margin from base to subapical portion; gill III broad and heart-like; gill VII leaf-like with round apex...................................................................... N. edentatus

- Superlinguae with row of hair-like setae along outer margin from base to apex; gill III split into 2 portions; gill VII leaf-like with blunt apical projection.............................................................. N. lamellosus sp. n.

3. Claws with denticles................................................................................... 4

- Claws without denticles................................................................................ 7

4. Claws with 2–3 denticles; gills V–VI each with arrow-like accessory lobe; pronotum expanded laterally................ 5

- Claws with more denticles (10–11); gills V–VI each with blunt apical projection; posterolateral margin of pronotum fixed to the side of mesonotum.................................................................... N. islamabadicus

5. Abdominal terga with oblique stripes; dorsal surface of femora with scattered simple stout setae....................... 6

- Abdominal terga without distinct markings; dorsal surface of femora with stout setae but apically pointed........ N. baekdu

6. Pronotum slightly wider than head; head width 1.4–1.8x of length; posterior margin of sternum IX straight.................................................................................................... N. maculatus sp. n.

- Pronotum slightly narrower than head; head width 1.4x of length; posterior margin of sternum IX concave......... N. baei

7. Pronotum with expanded anterolateral margin.................................................... N. ladakhensis

- Pronotum expanded laterally............................................................................ 8

8. Abdominal terga III–VIII with obvious markings laterally; trachea of gills invisible; gill VII ellipsoid.......... N. cristatus

- Abdominal terga I–IX with dark oblique stripes laterally; trachea of gills visible; gill VII banana-shaped....... N. zhiltzovae