Metrichia extrana, 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 : 308-310

Metrichia extrana sp. nov.

Figure 4

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 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 1.9 mm. Wings each strongly tapered from near its base, acute apically. Forewings each with jugal lobe.

Pregenital abdominal segments. Densely covered by short and slightly flattened and apically blunt setae. Tergum V with anterior margin produced mesally, bearing subpentagonal anterior mark covered by microsetae. Tergum VI with posterior margin slightly notched mesally and pair of internal pouches anteriorly, each with circular and setose opening to tergum; long, eye-shaped mesal mark covered by microsetae. Segment VII notched posteromesally ( Fig. 4A ).

Genitalia. Segment VIII shorter ventrally than dorsally ( Fig. 4B ); in ventral view, anterior and posterior margins strongly concave ( Fig. 4D ). Segment IX reduced dorsally, partially retracted within segments VII and VIII; in lateral view, slightly longer than 2x height of segment, tapering anteriorly, posterior margin oblique ( Fig. 4B ); in ventral view, anterior margin round, posterior margin almost straight mesally ( Fig. 4D ). Inferior appendages about 2/3 as long as segment IX, covered with small setae, each with apex round in lateral view ( Fig. 4B ) and acute in dorsal and ventral views ( Figs 4C, 4D ). Dorsal hooks slightly shorter than inferior appendages but positioned more anterior; in lateral view, bowed posteroventrad, each with small, digitate dorsomesal projection ( Fig. 4B ). Preanal appendages short and round, covered apically with small setae ( Fig. 4B ). Subgenital processes absent. Tergum X membranous, subtriangular, covered dorsally with microsetae ( Fig. 4C ). Phallus tubular, elongate, basal 1/3 twice as broad as distal 2/3, with two large, curved spines subapically arising at same level; apex slightly sclerotized, folded; internal sclerites absent; ejaculatory duct slightly sclerotized, not protruding apically ( Figs 4E, 4F ).

Remarks. Although the male genitalia of M. extrana sp. nov. superficially resemble those of M. lemniscata ( Flint 1972) , from Costa Rica and Panama, this new species is readily recognized from that by having two subapical phallic spines (a single, ribbon-like spine in M. lemniscata ). The new species is also easily distinguished from this and other Metrichia species by the unique modifications on segments V–VIII, particularly the dorsum of segment V produced anteromesally and the dorsum of segment VI with a pair of circular openings posterolaterally and a mesal eye-shaped process. In addition, the hairy appearance of the abdomen due to the large number of modified setae covering the segments also helps to identify this species.

Material examined. Holotype. Peru: Cusco: Quincemil , 3 km E, 13º13’03”S 70º43’40”W, 633 m, Malaise, 20.viii–01.ix.2012, RR Cavichioli, JA Rafael, APM Santos, DM Takiya leg., male ( MUSM).

Etymology. Extrana is a Spanish adjective meaning strange or weird, in reference to the peculiar modifications of the abdominal segments not previously described for Metrichia .

Figures

FIGURE 4. Metrichia extrana sp. nov. 4A, abdominal segments IV–VII, dorsal. 4B–4F, male genitalia: 4B, left lateral; 4C, dorsal; 4D, ventral; 4E, phallus, dorsal; 4F, phallus, left lateral. Abbreviations: IV = tergum IV; V = tergum V; VI = tergum VI; VII = tergum VII.