Dang N.T. 1967

Các loài mói và giõng mói tim thãy trong khu hê ðông vât không xu'o'ng sõng nu'óc ngot và nu'óc lo' miên Bac Vietnam [Nouveaux genres, nouvelles espèces de la faune des invertébrés des eaux donces et saumâtres du Nord Vietnam]. // Sinh Vàt – Ðia Hoc 6(3–4): 155–165. 

Ephemeroptera taxa described:

Heterogenesia chinei gen. & sp.n.
Ecdyonuroides vietnamensis gen. & sp.n.
Neoephemeropsis cuaraoensis sp.n.
Neoephemeropsis caenoides
Choroterpides minor sp.n.

TRANSLATION:

...

Family Ecdyonuridae

Ecdyonuroides gen. nov.

Projections of pronotum project backward. Gills wide, with apex pointed. Long projections on abdominal segments II–VIII. Maxillary palp 3-segmented, 3rd segment short and triangular. Labial palp 2-segmented, with segments very thick. Femora I–III wide, outer margin with thin setae. On upper side of femur III long spines. Length  of femur III equal to tibia and tarsus together. Claw thick, curved, with denticles.

Type species: Ecdyonuroides sumatrensis (Ulmer) (= Ecdyonurus sumatrensis Ulmer)

Discussion

...

Differs from Ecdyonurus by projections on abdomen, 3-segmented maxillary palp and wide labium.

Ecdyonuroides vietnamensis sp. nov.