Oecetis verrucula, 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 : 61-64

Oecetis verrucula sp. n. Figs 26, 44, 57, Map 5

Diagnosis.

This species is nearly identical in color and in the shape of the inferior appendages to Oecetis avara . Character similarities include, particularly, a prominent ventral lobe of the inferior appendage, which is very distinctly acutely angled with respect to the dorsal lobe, and also the general shape of the phallobase, which is short and strongly arched ventrally. The only definitive diagnostic character separating this species from Oecetis avara is the presence in Oecetis verrucula of a small preapical "rugose wart" on the ventral surface of the phallobase. Oecetis avara lacks this character, but may have the extreme apex of the phallobase slightly burred or ridged. A character state similar to that in Oecetis verrucula occurs in Oecetis sordida sp. n., which is otherwise quite different in morphology. Considering the relatively minor nature of the difference, it is possible that Oecetis verrucula should be considered a variant of Oecetis avara . However, because the range of variability in Oecetis avara still needs to be assessed, and also because the character state in Oecetis verrucula is consistent over a wide distribution in which it is nearly invariant, we thought it best to assign this form to its own species.

This species is most readily diagnosed by its coloration, yellowish with a tinge of brown, darker than Oecetis mexicana sp. n., and with relatively small and generally somewhat oval forewing spots, by the very prominent, acutely angled ventral lobe of the inferior appendage, and by the shape and structure of the phallobase, which has a small preapical “wart” on its ventral surface. The last character is considered diagnostic. Species that are nearly similar in size and occur in sympatry, Oecetis angularis , Oecetis protrusa , or Oecetis mexicana , are likely to have the forewing spots distinctly rounded and the inferior appendages, as viewed ventrally, to be more distinctly angled basally (compare Fig. 26E with Figs 3E, 22E, and 18F). Among these, Oecetis verrucula is most likely to be confused with Oecetis protrusa , because both have the inferior appendage acutely angled. Oecetis protrusa additionally differs from Oecetis verrucula in that the apex of the phallobase is distinctively shaped and somewhat protruding. Oecetis mexicana and Oecetis angularis both have the ventral lobe of the inferior appendage less protruding and not acutely angled. Oecetis angularis also differs by having the apex of the phallobase V-shaped in caudal view.

Adult.

Forewing length: male (7.8-8.5 mm), female (6.2-7.2 mm). Color generally pale yellowish-brown (darker than Oecetis mexicana ), legs somewhat paler. Antennae whitish with indistinct, narrow annulations at intersection of antennomeres. Forewing spots small or very small; spots at base of discal and thyridial cells and base of fork V largest, these usually distinct and somewhat ovate, other spots small and indistinct; veins of forewing chord moderately spaced, usually with s and r-m relatively closely spaced, m more widely spaced; chord with small spots at juncture of major veins; apical spots, at apices of major veins, indistinct, but usually evident. Setae along veins in apical part of forewing elongate, prostrate, laterally diverging. Fringe of setae along costal margin of forewing dense, short, not strongly projecting.

Male genitalia.

Segment IX very short, with elongate setae along posterolateral margin. Tergum X with narrow, deflexed mesal lobe, lobe relatively elongate, nearly uniform in width, or slightly tapered apically, apex with small sensilla; lobe continuous basoventrally with short, paired lateral membranous projections. Preanal appendage moderately elongate, length 2 ½– 3 times maximum width, simple in structure, apical setae elongate. Inferior appendage with rounded dorsal lobe and angularly projecting ventral lobe; ventral lobe elongate and strongly projecting, forming acute angle with dorsal lobe, posterior margin of ventral lobe, as viewed ventrally (Fig. 26E), with mesal margin only weakly bent near base; basomesal projection distinct, forming rounded projection 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, tubular, ventral margin rather strongly arched or curved, not angular, preapically with distinctive rugose wart (Fig. 26B); as viewed caudally, with apex U-shaped (Fig. 26C). Phallotremal sclerite prominent, basally forming short tubular collar, ventral margin projecting, apex acute; asymmetrical lateral sclerite present, usually on right side.

Holotype.

Male (pinned), COSTA RICA: Guanacaste: Hda. Tempisquito ( Pelón de la Altura), 1 km NE km 265, rt. 1, 10°50.400'N, 85°33.600'W, el 100 m, 18.vii.1987, Holzenthal, Morse, Clausen (UMSP) (UMSP000064973).

Paratypes.

MEXICO: Chiapas: nr. Pijijiapan, 5.vii.1965, P.J. Spangler, 1 male, 11 females (alcohol) (NMNH); Oaxaca: Rancho San Pablo, 17 km E Tehuantepec, 23.v.1981, C.M. & O.S. Flint, Jr., 3 males, 2 females (pinned) (NMNH); nr. Tehuantepec, Rt. 190, km 808, 8-9.vi.1967, Flint & Ortiz, 1 male (pinned) (NMNH); Sonora: Alamos, 17.iii.1961, D. Beers, 2 males (alcohol) (NMNH); Veracruz: La Gloria Cardel, --i.1938, J. Camelo G., 1 male, 1 female (alcohol) (NMNH); GUATEMALA: Río Matapa, 10 km SE Esquintla, 5-6.iii.1970, E. J. Fee, 5 males, 3 females (alcohol) (NMNH); Suchitepequez: Río Sis, 22 km S Finca La Maquina, 11.vi.1966, O.S. Flint, 1 male (pinned), 10 males, 1 female (alcohol) (NMNH); HONDURAS: Nacaome, 4.viii.1967, O. S. Flint, 5 males (pinned), 34 males, 2 females (alcohol) (NMNH); El Zamorano, 16.iv.1966, G.F. Freytag, 1 male, 3 females (alcohol) (NMNH); St. Barb., Casas Viejas, el 250 m, 20.v.1966, J.M. Natta, 23 males, 8 females (alcohol) (NMNH); Pespire, 1.viii.1967, O.S. Flint, Jr., 2 males, 15 females (alcohol) (NMNH); Río Humuya, NW Comayagua, 3.viii.1967, O.S. Flint, Jr., 1 males, 4 females (alcohol) (NMNH); Comayagua, Hotel los Remos, south side Lago Yojoa, 15.xi.1987, L. Knutson, 2 males, 9 females (alcohol) (NMNH); EL SALVADOR: Quezaltepeque, 11.ii.1965, S. & W.D. Duckworth, 1 male, 3 females (alcohol) (NMNH); NICARAGUA: Granada: Isla Zapatera, Costa La Perra, 11°45.883'N, 85°50.974'W, el 52 m, 18.vii.2001, Chamorro, Ruiz, Martinez, 5 males, 1 female (pinned) (UMSP); Reserva Silvestre Privada Domitila, stream, 11°42.261'N, 85°56.948'W, el 79 m, 26.vii.2001, Chamorro & López, 1 male, 3 females (pinned) (UMSP); Leon: between La Leona & amp; Izapa, 30.iv.1995, J.M. Maes, 1 male, 2 females (alcohol) (NMNH); Rivas: Río Las Lajas, ca. 2 km NW de El Genizaro, 11°21.53'N, 85°47.579'W, 1.vii.2000, L. Chamorro & J. Lacayo, 2 males (pinned) (UMSP); COSTA RICA: Río Seco, NW Esparta, 23.vii.1967, O.S. Flint, Jr., 3 males, 3 females (pinned), 1 male, 1 female (alcohol) (NMNH); 9 mi NW Esparta, 22.vii.1965, P.J. Spangler, 1 male, 2 females (alcohol) (NMNH); Las Canas, 13.vii.1965, P.J. Spangler, 8 males, 4 females (alcohol) (NMNH); Las Canas, Río Cordobicí, 26,vii.1967, O.S. Flint, Jr., 1 male (alcohol) (NMNH); Guanacaste: Colorado, 31.iii.1988, W. E. Steiner, J. M. Hill, J. M. Swearingen, J. M. Mitchell, 1 male (pinned) (NMNH); Parque Nacional Santa Rosa, Quebrada San Emilio, 10°51.720'N, 85°36.600'W, el 300 m, 27.vi.1986, Holzenthal, Heyn, Armitage, 1 male (pinned) (UMSP); Parque Nacional Santa Rosa, Río Poza Salada, 10°47.940'N, 85°39.120'W, el 10 m, 24.vii.1987, Holzenthal, Morse, Clausen, 1 male (pinned) (UMSP); Río Tempisquito, ca 3 km S route 1, 10°47.400'N, 85°33.120'W, el 75 m, 6.iii.1986, Holzenthal & Fasth, 14 males, 10 females (pinned), 240 males, 137 females (alcohol) (UMSP) (INBIO); Río Tizate, 7.2 km NE Canas Dulces, 10°46.380'N, 85°26.940'W, el 275 m, 28.vi.1986, Holzenthal, Heyn, Armitage, 1 male, 3 females (pinned), 6 males, 4 females (alcohol) (UMSP); same data as holotype, 6 males (pinned) 8 males, 2 females (alcohol) (UMSP).

Etymology.

This species is named Oecetis verrucula , as a diminutive of the Latin word verruca, a wart, and referring to the small preapical wart on the phallobase that is distinctive of this species.