Metrichia araza, 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 : 306-307

Metrichia araza sp. nov.

Figures 2 , 3

Description, male. Head. Wider than long, frontal margin convex, ocellar setose warts (o.s.w.) subtriangular, posterior setose warts (p.s.w.) transversely ellipsoidal with longitudinal length about 1/3 transverse width ( Fig. 2A ). Antennae each 17-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 ( Fig. 2B ).

Thorax. Metascutellum subtriangular ( Fig. 2C, m.t.c ). Length of each forewing: holotype 1.6 mm; paratypes 1.6–1.8 mm (n = 11). Wings strongly tapered from near their bases, acute apically. Forewings with apical forks II and III present; R1 vein short and not reaching wing margin; R4+5 vein fused to M1+2 basally; M1+2 vein fused to R3 sub-basally; Cu1 vein reaching wing margin; jugal lobe present ( Fig. 2D ). Hind wings with apical forks II, III and V present; various other veins fused or absent ( Fig. 2E ).

Pregenital abdominal segments. Sternum V with pair of membranous internal pouches in posterior area, each about 1/3 as long as segment, visible in dorsal view of cleared abdomen; tergum with weakly sclerotized tergite medially, subrectangular, slightly longer than wide; with pair of brushes of very long, curved, decumbent setae dorsolaterally beside tergite ( Fig. 3A ). Tergum VI with sclerotized rectangular tergite wider than long; pair of small, dark, slender internal sacs apparently arising between terga VI and VII submesally ( Fig. 3A ).

Genitalia. Segment VIII shorter ventrally than dorsally ( Fig. 3B ). Segment IX reduced dorsally, partially retracted within segments VII and VIII, covered with long flattened setae; in lateral view, twice as long as tall, tapering anteriorly, posterior margin oblique ( Fig. 3B ); in ventral view, anterior margin round, posterior margin excavated mesally ( Fig. 3D ). Inferior appendages less than half as long as segment IX, covered with small, flattened setae, apex bilobed in lateral view to form round dorsal and ventral projections; in ventral view, C-shaped, curved mesad, apically acute ( Fig. 3D ). Dorsal hooks almost as long as inferior appendages but positioned more anteriorly; in lateral view, bowed posteroventrad, each with elongate, digitate dorsomesal process directed anterodorsad ( Fig. 3B ). Preanal appendages short and round, covered apically with small setae ( Fig. 3B ). Subgenital processes absent. Tergum X membranous, subtriangular in dorsal view, covered apicodorsally with microsetae ( Fig. 3C ). Phallus tubular, elongate, basal half broad, two curved spines subapically arising at same level; apex slightly sclerotized, folded; internal sclerites absent; ejaculatory duct slightly sclerotized, straight, not protruding apically ( Figs 3E, 3F ).

Remarks. Metrichia araza sp. nov. is very different from other Peruvian species of Metrichia and shows close resemblance to M. talhada Santos, Takiya & Nessimian 2016 and M. tere Santos, Takiya & Nessimian 2016 , both from Brazil, with which it shares the C-shaped form of the inferior appendages in ventral view and segment V with a pair of membranous internal pouches. The new species is also similar to M. tere because of sternum IX with its posterior margin excavated mesally and the two subapical phallic spines arising at the same level. Metrichia araza sp. nov. differs from these by the dorsal hooks each bearing a dorsomesal projection, the apex of each inferior appendage forming two round projections in lateral view and by having a pair of small internal sacs arising between terga VI and VII.

Material examined. Holotype. Peru: Cusco: Quincemil, 19 km W, Rio Araza, Ponte 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).

Paratypes. same data as holotype, 50 males ( DZRJ) ; same data as holotype, 50 males ( INPA) ; same data as holotype, 45 males ( MUSM) ; Peru: Madre de Dios: Mazuco, 12 km E, Ponte Amanapu , 13º02’51”S 70º20’46”W, 382 m, Malaise, 18.viii.2012, RR Cavichioli, JA Rafael, APM Santos, DM Takiya leg., 1 male ( DZRJ).

Etymology. This new species is named in reference to the Río Araza, where the holotype was collected. The species epithet is a noun in apposition with unvarying gender.

Figures

FIGURE 2. Metrichia araza sp. nov. 2A, head, dorsal. 2B, antenna, apical segments. 2C, thorax, dorsal. 2D, right forewing, dorsal. 2E, right hind wing, dorsal. Abbreviations: A = anal veins, C = costa, Cu = cubital veins, M = medial veins, msc = mesoscutellum, mtc = metascutellum, o.s.w. = ocellar setal wart (paired), p.s.w. = posterior setal wart (paired), R = radial veins, Sc = subcostal vein.

FIGURE 3. Metrichia araza sp. nov. 3A, abdominal segments V and VI, dorsal. 3B–3F, male genitalia: 3B, left lateral; 3C, dorsal; 3D, ventral; 3E phallus, dorsal; 3F, phallus, left lateral. Abbreviations: V = tergum V; VI = tergum VI; VIII = segment VIII; IX = segment IX; X = tergum X.