Rhyacopsyche tumida, 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 tumida sp. nov.

Fig. 5

Type material. Holotype: Ecuador • ♂; Azuay, Rio Balao Grande in El Progreso [Sta. Isabel] ; 02.90989°S, 079.59665°W; el. 213 m; 21 March 2022; Ríos, Holzenthal, Pauls, Frandsen, Thomson, Amigo leg.; in alcohol; UMSP 000280911 ; UMSP . Paratypes: Ecuador • 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 000418191 ; UMSP • 1 ♂; same as for preceding; UMSP 000418192 ; MECN .

Diagnosis.

This species most closely resembles R. turrialbe Flint, 1971 , based on the overall form and appearance of abdominal segment IX and the inferior appendage. It can be most easily distinguished by the inferior appendage, which curves outward at the apex in R. tumida rather than curling inwards as in R. turrialbe .

Description.

Adult (male: n = 3). Forewing length 3.3–3.5 mm (male). 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 sinuate, posterolateral margin irregular with ventral projection; dorsolateral lobe of segment IX rounded with dark, peg-like setae, in dorsal view divided and rounded (Fig. 5 A, B ). Tergum X membranous, retracted inside segment IX, with basal projections, articulating with intermediate appendage (Fig. 5 A, B ). Intermediate appendage elongate, extending posteriad and bent dorsad, in lateral view apex curving slightly outward (Fig. 5 A, B ). Inferior appendage wide, setose, divided into dorsal and ventral lobes; dorsal lobe with posterior margin produced into blunt process, dorsal margin bearing large, bulbous, peg-like seta; ventral lobe simple, broadly rounded (Fig. 5 A ). Phallus basally tubular, elongate, apex membranous; central tubule with hooked apex; lateral process pointed (Fig. 5 D ).

Etymology.

Tumidus, Latin for “ swollen, ” referring to the shape of the thick seta on the dorsal lobe of the inferior appendage.

Distribution.

Ecuador (Table 1 ).

Figures

Figure 5. Rhyacopsyche tumida sp. nov. (UMSP 000280911), male genitalia A segments IX – X, lateral B segment IX – X, dorsal C segment IX, ventral D phallus, dorsal.