Thalerosphyrus lamuriensis sp. nov.

Ecdyonurus sumatranus Ulmer, 1939, nymph only, not female imago

Ecdyonuroides sumatrensis [sic] Dang, 1967, nymph only

Thalerosphyrus sumatranus Braasch & Soldán, 1984 and auct. seq. nymph

Material. Holotype: one male nymph, Indonesia, Western Sumatra, stream in primary forest at the Subang pass, 1000 m., 4.III.1929, Prof. Feuerborn leg. [ZMH]

Specimen kept in alcohol, except hindleg, gills and mouthparts mounted on 3 microscopic slides.

Paratypes: 32 nymphs, Indonesia, Sumatra Barat, Bukit Barisan, above Padang, creek, 1047m, 00° 56.739’S 100 32.730’E, (UN3), 8.XI.2011, M. Balke leg. [MZL, ZMH, LIPI] ; 4 nymphs, Indonesia, Sumatra Barat, Harau Canyon, stream, 540m, 0° 04.428’S 100° 38.002’E, (SUM009), 27.IX.2009, M. Balke & D. Amran leg. [MZL, LIPI] ; 5 nymphs, Indonesia, Sumatra Barat, Universitas Andalas campus, forest stream, 360m, 00° 54.666’S 100° 28.379’E, (UN1), 8.XI.2011, M. Balke leg. [MZL] ; 2 nymphs, Indonesia, Sumatra Barat, Bukit Tinggi to Palupuh, 680m, 0° 08.128’S 100° 15.514’E, (SUM010), 28.IX.2009, M. Balke & D. Amran leg. [ZMH] ; 6 nymphs, Indonesia, Sumatra Barat, Solok, Alahan Panjank Road, 1190m, 0° 56.345’S 100° 46.411’E, (SUM003), 24.IX.2009, M. Balke & D. Amran leg. [MZL]

Etymology. From Lamuri, an old Arabic name for the island of Sumatra.

Description. See Ulmer 1939, p.669, figs. 429–439. A supplementary description based on the paratype material will be published elsewhere.

Distribution. Only known from the island of Sumatra.

Discussion. Dang (1967) designated E. sumatranus as the type species of the genus Ecdyonuroides . There is little question that he had in mind the nymph of E. sumatranus when establishing the new genus, and not the female. But the holotype of E. sumatranus is the female imago designated explicitly by Ulmer (1939) and thus represents the name-bearing type. With its current assignment as Rhithrogena sumatrana, Ecdyonuroides Dang, 1967 must be considered as a junior subjective synonym of Rhithrogena Eaton, 1881 syn. nov. If the concept of Ecdyonuroides proposed by Dang (1967) later proves to be valid and different from the one of Thalerosphyrus, then another genus name should be proposed to encompass the affected taxa at that time.