Oecetis patula, Blahnik, Roger J. & Holzenthal, Ralph W., 2014

Blahnik, Roger J. & Holzenthal, Ralph W., 2014, Review and redescription of species in the Oecetis avara group, with the description of 15 new species (Trichoptera, Leptoceridae), ZooKeys 376, pp. 1-83 : 47-49

Oecetis patula sp. n. Figs 21, 49, Map 3

Diagnosis.

The most distinctive diagnostic character of Oecetis patula is the shape of the apex of the phallobase. In this species the apex of the phallobase is distinctly downturned and has its lateral margins explanate, causing it to appear wide in caudal view (more broadly U-shaped than Oecetis mexicana sp. n.). In the general shape of the inferior appendage, with the dorsal lobe relatively narrow and the basomesal process very weakly developed, it perhaps compares most closely to Oecetis maritza sp. n. Both species seem to lack an asymmetrical phallic sclerite, which is always present in Oecetis mexicana . Oecetis maritza differs in its smaller size, darker overall coloration, and in having a phallobase that is more narrowly U-shaped in caudal view. In general features Oecetis patula compares most closely to, and is most likely to be confused with, Oecetis mexicana , which is similar in size and general coloration, but has the apex of the phallobase more narrowly U-shaped in caudal view and always possesses an asymmetrical phallic sclerite. Also, in most of the specimens of Oecetis patula examined, the forewings spots were distinctly smaller than in Oecetis mexicana . However, in a couple of the specimens from Nicaragua the spots were relatively large, but the spots were then irregular in shape, V-shaped rather than distinctly rounded.

Adult.

Forewing length: male (8.1-8.5 mm), female (6.5 mm). Color pale yellowish, (slightly paler than Oecetis mexicana ). Antennae pale yellow with indistinct, narrow annulations at intersection of antennomeres. Forewing spots small, but distinct (smaller than those of Oecetis mexicana ); spots at base of discal and thyridial cells and base of fork V largest, sometimes forming deltoid spots in angle formed by fork; veins of forewing chord widely and usually nearly evenly spaced, with crossveins nearly perpendicular, or s and r-m veins slightly closer; chord with spots at juncture of major veins, those at opposite ends of chord larger, or chord itself sometimes pigmented; apical spots, at apices of major veins either small or large, with pigmentation extending beyond veins. Setae along veins in apical part of forewing elongate, semi-prostrate, laterally diverging. Fringe of setae along costal margin of forewing moderately dense, suberect.

Male genitalia.

Segment IX very short, with elongate setae along posterolateral margin. Tergum X with narrow, deflexed mesal lobe, lobe moderately elongate, uniform in width or somewhat lobulate apically, apex with small sensilla; lobe continuous basoventrally with short, paired lateral membranous projections. Preanal appendage moderately elongate, length about 3 times maximum width, simple in structure, apical setae elongate. Inferior appendage with relatively narrow, apically rounded dorsal lobe and angularly projecting ventral lobe; ventral lobe very weakly projecting, forming approximately right (Fig. 21A inset) to distinctly obtuse angle (Fig. 21A) with dorsal lobe, posterior margin of ventral lobe, as viewed ventrally (Fig. 21E), with distinctly angular bend near base; basomesal projection very weakly developed, scarcely (Fig. 21D inset) or not protruding (Fig. 21D), with short, stiff setae; dorsal lobe with stout, mesally-curved setae on dorsal margin and stout, ventrally-curved setae on mesal surface. Phallobase, as viewed laterally, short and tubular, distinctly curved or “arched” ventrally; apex, as viewed caudally, with ventral margin very broadly U-shaped, not keeled ventrally (Fig. 21C), apex not ridged or “burred.” Phallotremal sclerite rela tively prominent, basally forming short tubular collar, ventral margin projecting, apex acute; asymmetrical lateral sclerite apparently absent.

Holotype.

Male (pinned), GUATEMALA: Baja Verapaz: Rt 5, Km 156, Puente Las Burras, 22-24.vi.1966, Flint & Ortiz (NMNH) (UMSP000208338).

Paratypes.

NICARAGUA: Jinotega: Cerro Kilambé, stream nr. camp, 13°35.216'N, 85°42.722'W, el 1200 m, 13.vii.2001, Chamorro, Maes, Hernandez, Sanger, 5 males, 1 female (pinned) (UMSP).

Etymology.

This species is named Oecetis patula from the Latin word patulus, meaning open or spread out, and referring to the wide ventral apex of the phallobase of the species.