Rhyacopsyche decouxi, Thomson & Ríos-Touma & Holzenthal, 2025

Thomson, Robin E., Ríos-Touma, Blanca & Holzenthal, Ralph W., 2025, Additions to the genus Rhyacopsyche Müller, 1879 (Trichoptera, Hydroptilidae) in Ecuador, ZooKeys 1263, pp. 531-543 : 531-543

Rhyacopsyche decouxi sp. nov.

Fig. 3

Type material.

Holotype: Ecuador • ♂; Imbabura, Reserva Los Cedros, tributary to Rio Los Cedros ; 00.30374°N, 078.78229°W; el. 1312 m; 18–19 October 2011; Holzenthal, Ríos, Encalada, Acosta leg.; in alcohol; UMSP 000145864 ; UMSP . Paratypes: Ecuador • 4 ♂; same as for holotype; in alcohol; UMSP 000145864 ; MECN • 7 ♂ and 2 ♀; same as for holotype; in alcohol; UMSP 000145868 , UMSP 00145869 ; UMSP • 1 ♂; Azuay, Rio Chaucha & waterfall 1.2 km E La Iberia ; 02.89407°S, 079.50786°W; el. 700 m; 22 March 2022; Ríos, Pauls, Amigo leg.; in alcohol; UMSP 000418196 ; MECN • 1 ♂; Azuay, trib. to Rio Chaucha in San Antonio de Chaucha ; 02.90736°S, 079.41375°W; el. 1831 m; 23 March 2022; Holzenthal, Ríos, Amigo leg.; in alcohol; UMSP 000418195 ; UMSP • 1 ♂; Bolivar, Quebrada San Pablo, N of Chazojuan ; 01.37978°S, 079.15496°W; el. 1150 m; 20 March 2022; Ríos, Holzenthal, Pauls, Thomson, Amigo leg.; in alcohol; UMSP 000418194 ; UMSP • 1 ♂; Pichincha, Reserva Rio Bravo, Rio Bravo, upstream ; 00.07802°S, 078.73287°W; 19 November 2023; el. 1564 m; Holzenthal, Frandsen, Morabowen, Amigo leg.; pan trap; in alcohol; UMSP 000551405 ; UMSP .

Diagnosis.

Rhyacopsyche decouxi , new species, is also similar in appearance to R. rhamphisa . Characteristics found on the dorsolateral lobe, inferior appendage, and phallus make them very similar. Key differences, however, make it possible to separate the two. R. decouxi bears a prominent seta on the dorsal margin of the inferior appendage that is lacking in R. rhamphisa ; in addition, the shape of the inferior appendage when viewed ventrally is very different.

Description.

Adult (male: n = 15, female: n = 2). Forewing length 2.5–2.9 mm (male), 2.9–3.0 mm (female). Head unmodified, with 3 ocelli; antennae unmodified. Tibial spurs 1, 3, 4. Specimens brown in alcohol. Sternum VII with short mesoventral point. Male genitalia. Abdominal segment IX setose, anterolateral margin rounded, posterolateral margin convex; dorsolateral lobe of segment IX broadly truncate, with dark, peg-like setae, in dorsal view deeply divided and with rounded apex (Fig. 3 A, B ). Tergum X membranous, retracted inside segment IX, in dorsal view with lateral lobes (Fig. 3 A, B ). Intermediate appendage not apparent. Inferior appendage elongate, setose basally, dorsal margin produced basally and with prominent seta mesally; apex digitate, bearing prominent peg-like seta (Fig. 3 A, C ). Phallus basally tubular, elongate, membranous apex bearing series of thickened spines; central tubule with pointed apex adjacent to small, sclerotized plate; lateral process lanceolate (Fig. 3 D, E ).

Etymology.

Named in honor of the late José Decoux, founder and protector of the reserve, who died in 2024, leaving the enormous legacy of Los Cedros Reserve to future generations.

Distribution.

Ecuador (Table 1 ).

Figures

Figure 3. Rhyacopsyche decouxi sp. nov. (UMSP 000145864), male genitalia A segments IX – X, lateral B segment IX – X, dorsal C segments IX – X, ventral D phallus apex, dorsal E phallus apex, lateral.