Metrichia peruana, Rocha & Santos & Nessimian, 2023

Rocha, Isabela Cristina, Santos, Allan Paulo Moreira & Nessimian, Jorge Luiz, 2023, Taxonomic diversity of Ochrotrichiinae (Trichoptera: Hydroptilidae) from Peru with the description of ten new species, a new distributional record, and an updated checklist, Zootaxa 5353 (4), pp. 301-331 : 314

Metrichia peruana sp. nov.

Figure 8

Description, male. Head. Wider than long, frontal margin convex, ocellar setose warts subtriangular, posterior setose warts transversely ellipsoidal with longitudinal length about 1/3 transverse width. Antennae each 18-articulated, scape about 2x as long as wide, median flagellomeres each almost as long as wide and with blunt setae forming basal row, apical flagellomere with digitate apical process.

Thorax. Metascutellum subtriangular. Length of each forewing: holotype 1.2 mm. Wings strongly tapered from near bases, acute apically. Forewings each with jugal lobe.

Pregenital abdominal segments. Segment V with pair of membranous internal pouches in posterior area, about 1/4 as long as segment; pair of brushes of very long, curved, decumbent setae dorsolaterally; tergite weakly sclerotized, subrectangular, longer than wide ( Fig. 8A ). Tergum VI with tergite subrectangular, slightly wider than long ( Fig. 8A ). Pair of small, dark, slender internal sacs apparently arising between terga VI and VII dorsomesally ( Fig. 8A ).

Genitalia. Segment VIII shorter ventrally than dorsally ( Fig. 8B ). Segment IX reduced dorsally, partially retracted within segments VII and VIII, covered with long setae; in lateral view, twice as long as tall, tapering anteriorly, posterior margin oblique ( Fig. 8B ); in ventral view, anterior margin round, posterior margin widely excavated mesally ( Fig. 8D ). Inferior appendages subrectangular, about half as long as segment IX, covered with small setae, apex slightly excavated ( Fig. 8B ), bearing small mesal triangular projection ( Figs 8C, 8D ). Dorsal hooks elongate, about 1.5x as long as inferior appendages, angled ventrad apically, apical quarter slightly divergent in dorsal view ( Fig. 8C ). Preanal appendages elongate, about half as long as inferior appendages, covered apically with long setae ( Fig. 8B ). Subgenital processes absent. Tergum X membranous, truncate in dorsal view, covered dorsally with microsetae ( Fig. 8C ). Phallus tubular, elongate, basal third broad, two strong spines subapically arising from different levels; apex membranous; internal sclerites absent; ejaculatory duct slightly sclerotized, straight, not protruding apically ( Figs 8E, 8F ).

Remarks. Metrichia peruana sp. nov. resembles M. adamsae Flint & Bueno-Soria 1998 and M. malada , both recorded from Peru, based on overall shape of the inferior appendages, each of which bears a subapicomesal spine and elongate dorsal hooks each ending in a small point. However, the new species is easily distinguished from M. adamsae by having the spines of the phallus arising at different levels and by the more nearly round shape of the preanal appendages. It also differs from M. malada in that segment IX is only twice as long as tall, not three times as long as tall, and by lacking the very distinct ejaculatory duct at midlength of the phallus. The small lateral pouches described in M. malada , which appear beyond the posterior margin of tergum VI, possibly refer to the same small internal sacs seen between segments VI and VII of M. peruana sp. nov. The internal pouches of segment V are elongate in M. malada , but round in the new species. According to Flint & Bueno-Soria (1998), M. adamsae seems to lack abdominal modifications anterior of the genitalia.

Material examined. Holotype. Peru: Cusco: Quincemil, 19 km W, Río Araza, Puente Saucipata , 13º20’10”S 70º50’57”W, 874 m, Malaise, 23–31.viii.2012, RR Cavichioli, JA Rafael, APM Santos, DM Takiya leg., male ( MUSM).

Etymology. Peruana is the Spanish adjective for peruvian, in reference to the country of origin of the holotype.

Figures

FIGURE 8. Metrichia peruana sp. nov. 8A, abdominal segments V–VII, dorsal. 8B–8F, male genitalia: 8B, left lateral; 8C, dorsal; 8D, ventral; 8E, phallus, dorsal; 8F, phallus, left lateral. Abbreviations: V = tergum V; VI = tergum VI; VII = tergum VII.