Metrichia major, 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 : 312-314

Metrichia major sp. nov.

Figures 6 , 7

Description, male. Head. Wider than long, frontal margin convex, ocellar setose wart subtriangular, posterior setose wart transversely ellipsoidal with longitudinal length about 1/3 transverse width. Antennae each 28-articulated, scape and median flagellomeres each about 2x as long as wide and with blunt setae forming basal row on each flagellomere, apical flagellomere with digitate apical process ( Fig. 6A ).

Thorax. Metascutellum subtriangular. Length of each forewing: holotype 3.8 mm. Wings strongly tapered from near base, acute apically. Forewings each with jugal lobe.

Pregenital abdominal segments. Segment V with pair of elongate membranous internal pouches in posterior area, about 1/2 as long as segment; its tergite rectangular, more than 1.5X as long as wide ( Fig. 7A ). Tergum VI with tergite bearing tiny heavily sclerotized area mesally ( Fig. 7A ). Pair of small, dark, round internal sacs apparently arising between terga VI and VII dorsomesally ( Fig. 7A ). Sternum VII with triangular ventromesal process ( Fig. 7B ).

Genitalia. Segment VIII shorter ventrally than dorsally ( Fig. 7B ). Segment IX reduced dorsally, partially retracted within segments VII and VIII, covered with long setae; in lateral view, almost 2.5x as long as tall, tapering anteriorly, posterior margin nearly vertical ( Fig. 7B ); in ventral view, shield-shaped, posterior margin almost straight mesally ( Fig. 7D ). Inferior appendages about 2/3 as long as segment IX, each tapering to acute ventral apex, posterolateral margin dentate ( Fig. 7B ); in ventral view, semicircular with mesal margins nearly straight ( Fig. 7D ). Dorsal hooks slightly longer than inferior appendages and positioned more anterior; in lateral view, slightly bowed posteroventrad with small, anteroventral projection ( Fig. 7B ). Preanal appendages short and round, covered apically with small setae ( Fig. 7B ). Subgenital processes absent. Tergum X membranous, truncate, covered dorsally with microsetae ( Fig. 7C ). Phallus tubular, elongate, basal 1/3 two–three times as broad as apical 2/3, two curved spines subapically arising at same level, in lateral view bowed posterodorsad ( Fig. 7F ); in dorsal view, spines diverging; phallus apex slightly sclerotized, rounded; internal sclerites absent; ejaculatory duct slightly sclerotized, not protruding apically ( Fig. 7E ).

Remarks. Metrichia major sp. nov. shares some similarities with M. triquetra Bueno-Soria & Holzenthal 2003 from Costa Rica and Panama in the form of the inferior appendages and dorsal hooks, but has highly distinctive male abdominal features that make it different from its congeners, such as the following: tergite V is much longer than wide, bearing a pair of long, cylindrical internal pouches internally; tergum VI has a tiny dark spot mesally; sternum VII has a ventromesal process; in segment IX, dorsal hooks are robust, crossing each other subapically in dorsal and ventral views. In relation to the other species of Metrichia herein described, Metrichia major sp. nov. has longer antennae, each with 28 flagellomeres; flagellomeres are each 2x longer than wide, except for the most basal flagellomeres. This species is also remarkable for its large body size and also for having been found in a highaltitude region from the eastern slope of the Andes.

Material examined. Holotype. Peru: Cusco: Upispata, Río Puica , 13º35’73”S 70º58’35”W, 2879 m, Malaise, 30.viii.2012, RR Cavichioli, JA Rafael, APM Santos, DM Takiya leg., male ( MUSM).

Etymology. Named for the holotype’s distinctly larger body size, one of the largest species of Metrichia described so far; the feminine (and masculine) comparative adjective of magnus.

Figures

FIGURE 6. Metrichia major sp. nov. 6A, antenna.

FIGURE 7. Metrichia major sp. nov. 7A, abdominal segments V–VII, dorsal. 7B–7F, male genitalia: 7B, left lateral; 7C, dorsal; 7D, ventral; 7E, phallus, dorsal; 7F, phallus, left lateral. Abbreviations: V = tergum V; VI = tergum VI; VII = tergum VII.