Metrichia iracema, Neto & Passos, 2024

Neto, Jaime De Liege Gama & Passos, Mahedy Araujo Bastos, 2024, Two new species of Metrichia Ross 1938 (Trichoptera: Hydroptilidae) from the Brazilian Amazon biome, Zootaxa 5537 (1), pp. 133-140 : 134-136

Metrichia iracema sp. nov.

( Figs 2A–2E )

Diagnosis. This new species does not fit well into any of the Metrichia Species Groups as defined by Flint (1972) and Bueno-Soria & Holzenthal (2003). Metrichia iracema sp. nov. is very similar to Metrichia tere Santos, Takyia & Nessimian 2016 due to inferior appendages elongate, each with an acute apical projection and a deep C-shaped notch in ventral view. The new species can be distinguished from M. tere by the tergum X apex slightly incised in the new species and truncate in M. tere ; and by the dorsal hook, in lateral view, with a longer dorsal branch extending anterad in the new species, and without a dorsal branch in M. tere . Additionally, the phallus of the new species has a folded apex while in M. tere it is round. For further information and illustrations of M. tere , see Santos et al. (2016).

Description. Adult male. Forewing length 2.1 mm (Holotype), ranging from 1.9–2.1 mm (n = 10). General color (in alcohol) dark brown. Head without modifications, with three ocelli; dorsally with two pairs of setal warts; ocellar pair appressed on midline, each subtriangular; occipital pair large, ellipsoid. Antennae unmodified, 18- articulated. Maxillary palpi each 5-articulated; labial palpi 3-articulated. Mesoscutellum broadly subtriangular and with transverse suture. Wing venation reduced in both wings. Anterior femur with acute apicodorsal process. Tibial spur formula 1-3-4. Abdominal segment V bearing pair of brushes of very long setae dorsolateraly ( Fig. 2A , dlb) and lateral external sacs ( Fig. 2A , les); one pair of internal abdominal sacs arising between segments V and VI, another pair arising between abdominal segments VI and VII ( Fig. 2A , ias). Sternum VII without ventromesal process. Segment VIII shorter ventrally than dorsally.

Male genitalia. Segment IX membranous dorsally; in lateral view ( Fig. 2B ), tapered anteriorly; in ventral view ( Fig. 2C ), ogival and round anteriorly, concave posteriorly ( Fig. 2C ); in dorsal view ( Fig. 2D ), with round posterior margin. Inferior appendages, in lateral view ( Fig. 2B ), with dorsal margin convex, ventral margin concave, and apex tapering to acute posteroventral projection; in ventral view ( Fig. 2C ), each with deep C-shaped notch in apical half; in dorsal view ( Fig. 2D ), each elongate, with acute apical projection below 45° apicodorsal angle ( Fig. 2D ). Dorsal hooks each approximately 3/4 as long as inferior appendages ( Fig. 2D ); in lateral view ( Fig. 2B ), each with downturned posterior apex and long dorsal branch extending anterodorsad. Subgenital plate apparently absent. Tergum X semi-membranous, its apex slightly incised mesally in dorsal view ( Fig. 2D ). Phallus tubular, elongate, constricted at mid-length; with two stout subapical spines: the more basal one large and basally curved; the apical one medium-size ( Fig. 2E ); apex membranous and folded; ejaculatory duct sclerotized, slightly sinuous, not protruding apically ( Fig. 2E ).

Female, Pupa, Larva, and Egg. Unknown

Holotype male. BRAZIL: Roraima: Iracema municipality, Campos Novos side road (Fazenda Rancho Fundo), small order stream, 2°21’26.22”N, 61°23’38.98”W, 209 m a.s.l., 16 Mar. 2018, Pennsylvania light trap, J.L. Gama Neto, leg. (alcohol; CEIPC).

Paratypes. Same data as holotype, 9 males (CEIPC) .

Distribution. Roraima state (type-locality)

Etymology. This new species is named in reference to the Iracema municipality, where the type locality, Campos Novos side road, is located.

Figures

FIGURE 2. Metrichia iracema sp. nov. 2A, Male abdomen, dorsal. 2B–2E, Male genitalia: 2B, left lateral; 2C, ventral; 2D, dorsal; 2E, phallus, ventral. dlb = dorsolateral hairbrush, les = lateral external sac, ias = internal abdominal sac.