Oecetis avara (Banks)

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 : 17-21

Oecetis avara (Banks) Figs 5, 13, 14, 40, 41, Map 2

Setodes avara Banks 1895: 316. [holotype male, Sherbrook Canada, pinned with genitalia in vial, MCZ type 11553].

Oecetina avara (Banks): Banks 1899: 214.

Oecetodes avara (Banks): Ulmer 1905: 129.

Oecetis avara (Banks): Sibley 1926: 105, 189; Betten 1934: 269 (plate 34, Figs 1-3) [description, illustration]; Ross 1944: 240 (figures 813, 818A, 828) [description, illustration]; Denning 1956: 267 (fig. 10: 34d) [illustration]; Smith and Lehmkuhl 1980: 641 (Figs 3-4, 6, 8, 11, 15, 17, 19-20, 22, 24, 27-28, 35-36, 39, 42, 44, 49, 50) [description, illustration, distribution]; Bueno and Flint 1980: [distribution - Mexico, Central America, Venezuela]; Bueno-Soria 1981: 111 (fig. 5A) [illustration only]; Flint 1981: 96 (fig. 364) [illustration, distribution - Colombia]; Botosaneanu and Alkins-Koo 1993: 35 [distribution - Trinidad & Tobago]; Flint 1996a: 104 [distribution - Trinidad & Tobago]; Flint 1996b: 423 [distribution - Peru]. Moulton and Stewart 1996: 150 (fig. 407) [illustration, distribution]; Rueda Martín et al. 2011: 21 (fig. 2A-F) [illustration, distribution - Bolivia].

Oecetis (Oecetodes) avara (Banks): Fischer 1966: 153; 1972: 150.

Oecetis (Pseudosetodes) avara (Banks): Chen 1993 (unpublished): (Figs 27 A–D, J-M) [description, illustration, distribution].

Diagnosis.

This species is similar to and most likely to be confused with Oecetis houghtoni sp. n., especially due to their sympatric distributions and relatively minor morphological differences. Unfortunately, the range of variation for the 2 species has not been fully established and specimens from some localities may not be currently diagnosable if they do not conform closely to the holotypes for the 2 species (see remarks section following the species description). The holotype of Oecetis avara is characterized by a very well developed ventral lobe of the inferior appendage that forms a prominent, acutely angled projection. The ventral margin is distinctly elongate (see Figs 11-14 for comparison to Oecetis houghtoni ). Some evidence of “wrinkling” is apparent at the point of articulation between the dorsal and ventral lobes; this is distinctly more noticeable than in Oecetis houghtoni due to the sharper angle of articulation. Also, as compared to Oecetis houghtoni , the phallobase is usually more distinctly sclerotized and arched ventrally, with its apex strongly downturned and very finely striate, often with the extreme apex slightly ridged or burred. Unfortunately, characters of the phallobase are subtle and also variable within the 2 species and thus may not always be completely diagnostic. Although the holotype of Oecetis avara itself is grayish-brown in color, with forewings only weakly spotted (possibly as a result of the specimen being somewhat faded), specimens from most areas of its distribution, including those from Minnesota, are distinctly lighter in color than Oecetis houghtoni and also have more prominent forewing spots. In Minnesota, Oecetis avara can be distinguished from Oecetis houghtoni by color alone (Figs 40 and 41).

Despite the close similarity and difficulty of distinguishing Oecetis avara from Oecetis houghtoni , another species that closely resembles Oecetis avara , both in color and genitalic aspects, is Oecetis verrucula sp. n. from Central America. The only significant difference is the possession of a small rugose wart or projection preapically on the phallobase in Oecetis verrucula , similar to the character state in Oecetis sordida , sp. n. This character is absent in Oecetis avara , but suggested by the fine striations often observed near the apex of the phallobase. COI barcode data (Fig. 58) also suggest that Oecetis avara and Oecetis verrucula are more closely related to each other than to Oecetis houghtoni . Rationale for treating Oecetis verrucula as a separate species is discussed in its diagnosis and description.

Adult.

Forewing length: male (8.2-10.3 mm), female (7.5-8.7 mm). Color generally pale yellowish-brown (slightly darker than Oecetis mexicana sp. n., paler than Oecetis houghtoni sp. n.). Antennae whitish with indistinct, narrow annulations at intersection of antennomeres. Forewing spots small, but distinct; spots at base of discal and thyridial cells and base of fork V largest, other spots indistinct; veins of forewing chord relatively widely spaced (wider than Oecetis houghtoni sp. n.), either evenly spaced or s and r-m veins slightly closer; chord with crossveins pigmented or with small spots at juncture of major veins; apical spots, at apices of major veins, indistinct, but usually evident, pigmentation extending slightly beyond veins. Setae along veins in apical part of forewing only moderately elongate, semi-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, apex of lobe tapered or rounded, with small sensilla; lobe continuous basoventrally with short, paired lateral membranous projections. Preanal appendage moderately elongate, length 2-3 times maximum width (longer, on average, than Oecetis houghtoni sp. n.), simple in structure, apical setae elongate. Inferior appendage with prominent rounded dorsal lobe and angularly projecting ventral lobe; projection of ventral lobe prominent and strongly protruding, typically forming acute angle with dorsal lobe, angle usually abrupt, causing appendage at basal angle to be somewhat “wrinkled;” posterior margin of dorsal lobe evenly rounded, not angulate; posterior margin of ventral lobe, as viewed ventrally (Fig. 5F), only weakly bent near base; basomesal projection of appendage rounded, with short, stiff setae; dorsal lobe with stout, mesally-curved setae on dorsal margin and stout, ventrally-curved setae on mesal surface. Phallobase very short, tubular basally, ventral apex strongly down curved, often noticeably sclerotized, with minute striations; ventral apex, as viewed caudally, U-shaped (Fig. 5C). Phallotremal sclerite prominent, basally forming short tubular collar, ventral margin projecting, apex acute; asymmetrical lateral sclerite present.

Material examined.

CANADA: Quebec: Sherbrook, male holotype (pinned) (MCZ); USA: Alabama: Bibb Co., Little Cahaba River, 4 mi NE Sixmile, 23.v.1988, C.M. & O.S. Flint, Jr., 1 male (pinned) (NMNH); Florida: Jackson Co., Chipola River at County Road 280, 1.5 mi E Oakdale, 11.vi.1995, V.L. Nations & M.J. Howe, 6 males, 4 females (pinned) (UMSP); Kansas: Clark Co., 12 mi W, 5 mi S Columbus, 8-9.vi.1976, G.F. Hevel, 2 males (pinned) (NMNH); Maryland: Montgomery Co., Potomac River, Carderock, 27.viii.1981, Flint & Butler, 1 male (pinned) (NMNH); Minnesota: Aitkin Co., Mississippi River, County Road 3, 47°01.417'N, 93°16.5000'W, 12.vii.2000, D.C. Houghton, 321 males, 497 females (alcohol) (UMSP); Aitkin Co., Hay Lake, Hay Lake State Park, 46°57.500'N, 93°13.000'W, 12.vii.2000, D.C. Houghton, 1 female (alcohol) (UMSP); Anoka Co., Coon Creek, confl. Mississippi River, 45°08.000'N, 93°17.000'W, 10.vii.2000, D.C. Houghton, 13 males, 8 females (alcohol) (UMSP); Blue Earth Co., Minnesota River, Mile 112, Sibley Park, Mankato, 11.vii.1979, N. Potthoff, 1 male, 1 female (alcohol) (UMSP); Blue Earth Co., Minneopa Creek, Minneopa State Park, 44°09.034'N, 94°05.500'W, 10.vi.2000, D.C. Houghton, 1 male, 1 female (alcohol) (UMSP); Blue Earth Co., un. sp. 1, Minneopa State Park, 44°09.667'N, 94°05.500'W, 10.vi.2000, D.C. Houghton, 1 male, 2 females (alcohol) (UMSP); Blue Earth Co., Le Seur River, County Road 16, public access, 44°04.916'N, 94°00.583'N, 11.vi.2000, D.C. Houghton, 17 males, 13 females (alcohol) (UMSP); Blue Earth Co., Maple River, County Road 166, public access, 44°00.034'N, 94°03.083'W, 11.vi.2000, D.C. Houghton, 198 males, 97 females (alcohol) (UMSP); Brown Co., un. sp., Cottonwood River, Flandrau State Park, 44°17.333'N, 94°28.916'W, 09.vi.2000, D.C. Houghton, 6 males, 17 females (alcohol) (UMSP); Brown Co., Cottonwood River, Flandrau State Park, 44°17.545'N, 93°28.134'W, 02.viii.1999, D.C. Houghton, 14 males, 1 female (pinned), 96 males, 53 females (alcohol) (UMSP); Chisago Co., Sunrise River at Kost Dam County Park, ca. 1.5 km S Kost, 45°28.75'N, 92°52.54'W, el 280 m, 13.vii.2004, Holzenthal et al., 3 males, 3 females (pinned) (UMSP); Crow Wing Co., Pine River, County Road 11, public access, 46°34.583'N, 94°01.834'W, 16.ix.2000, D.C. Houghton, 3 males, 2 females (alcohol) (UMSP); Crow Wing Co., Pine River, County Road 11, 46°34.333'N, 94°02.000'W, 29.vi.2000, D.C. Houghton, 214 males, 222 females (alcohol) (UMSP); Fillmore Co., Middle Br. Root River, Co. Rd. 21, ca. 5 mi NW Lanesboro, 43°49.080'N, 92°0.900'W, el 283 m, 13.vii.1991, R.J. Blahnik, 1 male (pinned) (UMSP); Fillmore Co., Spring Valley, 15.vi.1935, 1 male (pinned) (UMSP); Koochiching Co, Rainey R., confl. Little Fork River, State Highway 11 nr. International Falls, 48°31.174'N, 93°34.174'W, 12.vii.1999, D.C. Houghton, 983 males, 1461 females (alcohol) (UMSP); Koochiching Co., Big Fork River, State Highway 11, public access, 48°30.700'N, 93°42.754'W, 12.vii.1999, D.C. Houghton, 35 males, 5 females (pinned), 421 males, 203 females (alcohol) (UMSP); Koochiching Co., Little Fork River, Minn. F.S., 17.vii.1968, E.F. Cook, 1 male (alcohol) (UMSP); Koochiching Co., Tamarac River, Pine Island State Forest, Balsiger F.R., 7 km E Waskish, 48°09.526'N, 94°22.950'W, 23.vii.1999, D.C. Houghton, 1 female (pinned) (UMSP); Lyon Co., Redwood River, Camden State Park, 44°22.452'N, 95°55.315'W, 06.vi.2000, D.C. Houghton, 1 male (alcohol) (UMSP); same locality, 31.vii.1999, D.C. Houghton, 1 male, 2 females (pinned) (UMSP); McLeod Co., Otter Creek, County Road 01, 44°53.667'N, 94°03.33'W, 22.vi.2001, D.C. Houghton, 2 males (alcohol) (UMSP); Morrison Co., Mississippi River, Charles Lindberg State Park, 45°57.000'N, 94°23.333'W, 24.vi.2000, D.C. Houghton, 2 males (alcohol) (UMSP); Pine Co., Kettle River, Banning State Park, 46°10.000'N, 92°50.000'W, 28.vi.2001, D.C. Houghton, 1 male (alcohol) (UMSP); Pine Co. Kettle River, 9.viii.1991, L.J. Luedeman, 4 males, 2 females (alcohol) (UMSP); Ramsey Co., St. Paul, University Farm, A.A. Granovsky, 20.viii.1935, 1 male (pinned) (UMSP); Rock Co., Rock River, County Road 1, 43°32.666'N, 96°11.917'W, 07.vi.2000, D.C. Houghton, 9 males, 6 females (alcohol) (UMSP); Swift Co., Pomme de Terre River, State Road 12 rest area, 45°17.450'N, 95°58.745'W, 335 m, 29.vii.1999, D.C. Houghton, 7 males, 5 females (pinned) (UMSP); Wright Co., North Fork Crow River, public access, 45°05.500'N, 93°52.000'W, 17.ix.2000, D.C. Houghton, 1 male, 1 female (alcohol) (UMSP); Wright Co., North Fork Crow River, County Road 115, 45°05.500'N, 93°52.333'W, 27.vi.2001, D.C. Houghton, 25 males, 11 females (alcohol) (UMSP); Wright Co., Deer Lake, County Road 108, 45°08.500'N, 93°54.667'W, 27.vi.2001, D.C. Houghton, 2 females (alcohol) (UMSP); Yellow Medicine Co., Yellow Medicine River, confl. Minnesota River, Upper Sioux Agency State Park, 44°44.319'N, 95°25.904'W, 30.vii.1999, D.C. Houghton, 43 males, 30 females (alcohol) (UMSP); Yellow Medicine Co., Minnesota River, Mile 243.9, T115N, R38W, S28, 14.viii.1980, N. Potthoff, 5 males, 20 females (alcohol) (UMSP); Yellow Medicine Co., Minnesota River, picnic area, Upper Sioux Agency State Park, 44°44.393'N, 95°27.306'W, 122 m, 30.vii.1999, D.C. Houghton, 10 males, 1 female (pinned) (UMSP); New York: Warren Co., Hudson River, Riparius, 43°39.5'N, 73°53.8'W, 29.vii.1996, C.M. & O.S. Flint, Jr., 2 males (pinned) (NMNH); Wisconsin: Polk Co., St. Croix Falls, 29.viii.1937, L.R. Penner, 2 males, 10 females (pinned) (UMSP).

Remarks.

Mexican, Central, and South American specimens identified previously as Oecetis avara have been transferred to a number of new species in this paper. Some North American material has also been transferred to another new species, Oecetis houghtoni . Most North American material examined was from Minnesota, where Oecetis avara and Oecetis houghtoni co-occur, sometimes at the same location. In Minnesota the 2 species are distinguishable by color attributes and also by minor genitalic characters. Available COI barcode data are consistent with the recognition of 2 species and conform to the morphological differences noted (Fig. 58). Only a limited amount of material from other localities in North America was examined. Some material examined from other localities conformed to the differences noted in the holotypes of the 2 species, and these are included in the materials examined list above, but specimens from other localities could not always be confidently identified. This may either represent variation within the 2 species, or additional unidentified species. A more extensive study of North American material is necessary to determine this, but was outside the scope of the current study. Figs 28 and 29-30 illustrate some of the variation encountered. See also the remarks section under Oecetis houghtoni .

The illustration of Oecetis avara (Fig. 5) is taken from the holotype specimen. The holotype was reported by Smith and Lehmkuhl (1980) as having the phallic structure badly damaged, but this was not evident in our examination of the holotype. The species has been illustrated by a number of authors, but many of the illustrations vary from the genitalia of the holotype specimen. Although Smith and Lehmkuhl (1980) reported examining the type, the specimen illustrated was apparently a specimen from Saskatchewan determined to be Oecetis avara , and not that of the type itself. Due to the minor differences among species in the Oecetis avara group, it is usually difficult to state conclusively which species was illustrated by different authors. Only the illustrations provided by Betten (1934) and Moulton and Stewart (1996) conform closely enough to the holotype to be confidently identified as Oecetis avara . The illustration by Bueno-Soria (1981) is also similar to the holotype of Oecetis avara , but may have been based on Oecetis verrucula sp. n., which occurs in Mexico and whose diagnostic ventral wart may have been omitted, since it is a relatively minor feature.