Liancalus sonorus Runyon & Hurley

Runyon, Justin B. & Hurley, Richard L., 2015, A revision of the Nearctic species of Liancalus Loew (Diptera, Dolichopodidae), ZooKeys 483, pp. 97-147 : 133-136

Taxon classification Animalia Diptera Dolichopodidae

Liancalus sonorus Runyon & Hurley sp. n. Figs 2B, 3E, 5B, 10B, 13, 16F

Diagnosis.

Males and females are most similar to Liancalus genualis , but can be distinguished by having 2 intra-alar setae, whereas Liancalus genualis only has 1 intra-alar seta. Males are further distinguished by having tarsus I with tarsomere 2 very short (Fig. 3E), cerci long (Fig. 2B), and wing as in Fig. 5B.

Description.

Male. Body length 7.5-8.25 mm, wing length 6.5-7.0 mm. Head: Face nearly parallel-sided above frontoclypeal suture, slightly widening below suture; with dense silver-gray pollen along eyes that is otherwise sparse revealing violet and green-blue reflections. Frontoclypeal suture near mid-face, distinctly bulging. Eyes with minute hairs between facets; ommatidia the same size throughout. Vertex with dense silver-gray pollen along eyes that is sparser medially revealing violet, green-blue, and coppery reflections. Ocellar tubercle prominent with 2 large setae; vertical setae two-thirds size of ocellar setae, on a small elevation; 2 postocellar setae similar in size to vertical setae; postocular setae half the length of vertical setae with approximately dorsal one-half black (approximately 12 black setae), remainder white and more slender and slightly longer. Ventral postcranial hairs (beard) wholly white. Palpus black, with rather dense silver pollen and black setae that are most dense basally, with brown pollen around insertion of these basal setae. Antenna black, first flagellomere a little longer than wide, rounded apically, arista inserted just before midpoint of dorsal edge.

Thorax: Scutum with bronze ground color that is mostly obscured by blue-green-violet stripes along acrostichal setae, dorsocentral setae, and around postalar area; stripe along acrostichal setae pale green and narrower than stripes along dorsocentral setae; posterior slope of scutum with two large lateral blue-green-violet spots; notopleuron and postpronotum (humerus) covered with dense silver pollen, humerus usually with some violet-green reflections; 6 dorsocentral setae; 1-13 acrostichal setae in a single row; 2 notopleural setae; postpronotum with 1-2 strong setae and often a few smaller hairs or setae; 2 presutural intra-alar setae; 1 presutural and 2 postsutural supra-alar setae; 1 postalar seta; scutellum dark metallic bronze with 6 (rarely 7) large marginal setae (3 per side), no additional hairs; proepisternum with 1 dorsal and 1 ventral tuft of white hairs. Pleura metallic green-bronze, covered with dense silver-gray pollen, without setae or hairs.

Legs: Coxae concolorous with pleura; remainder of legs dark metallic green-bronze, dusted with silver pollen; femoral ‘knees’ narrowly orange. Coxa I uniformly covered with white, slender hairs on anterior surface (length of hairs subequal to width of coxa I), with a few black, slender setae at apex. Coxa II with scattered white hairs anteriorly (those at apex longer and stouter), a couple black setae at apex, and a black ad seta just beyond 1/2. Coxa III with a black dorsal seta near 1/2. Femur II with row of short (≤ width of femur) posterior to pv setae on distal half, those near middle of femur white, longest and becoming black and shorter apically. Tarsus I(2) short (length subequal to width), slightly thickened, with ventral brush of setulae (Fig. 3E). Ratios of tibia:tarsomeres for leg I: 18-8-2-4-3-2; for leg II: 26-23-9-4-2-2; for leg III: 33-16-15-4-2-2.

Wing (Fig. 5B): Hyaline, with anterior third somewhat brownish and a diffuse brown spot near 2/3 between R4+5 and M1; with a longitudinal spurious vein between R4+5 and M1 that is arched on apical third of wing and terminates near midpoint of a nearly circular, translucent, apical spot that is white in certain lights; this spot enclosed within a small, brown, apical cloud. Calypter yellow with a fan of long, pale yellow setae at apex. Halter pale yellow.

Abdomen: Cylindrical, elongate (Fig. 2B), bronze with large metallic blue-green spots with dense silver pollen laterally at base of T1-T4 which do not meet dorsally (except occasionally on T1 which is largely blue-green). T5 metallic green dorsally with sparse silver pollen. T6 wholly metallic green with sparse silver pollen. T1-T3 and base of T4 with white hair laterally, longest on T1 and T2. Sternites bronze with silver-gray pollen. S1 bare except for lateral tuft of 3-5 white hairs at extreme base. S2 and S3 with sparse white hairs. S4 mostly bare. T5 with a few white hairs ventrally and a row of black setae along posterior margin. Hypopygium (Fig. 10B): cerci almost as long as abdomen, slender, cylindrical (though often shriveled when dried), sparsely covered with whorls of long, pale yellow setae.

Female. Body length 6.5-7.0 mm, wing length 6.5-7.0 mm. Similar to male except for face wider; palpus slightly larger and more uniformly covered with black setae. Tarsus I(2) normal, not unusually short or thickened. Wing as in Fig. 16F.

Etymology.

This species is named for its known distribution: most specimens were collected in the Sky Island mountain ranges in the Sonoran Desert region (Fig. 13).

Remarks.

Specimens were collected in April-June prior to onset of the summer monsoon.

Robinson (1970b: 57) reports Liancalus genualis from Mexico (Guerrero) but this single specimen "differs from the eastern North America material by … the presence of a row of small acrostichal setae". This specimen could not be located, but is probably Liancalus sonorus .

Distribution.

Liancalus sonorus is known from the southwestern U.S. and neighboring Mexico (Fig. 13).

Type material.

HOLOTYPE ♂, labeled: "ARIZONA: Cochise Co./ Ramsey Canyon/ Huachuca Mtns. 5500'/ 23-IV-2002/ R. Hurley & J. Runyon"; "HOLOTYPE/ ♂ Liancalus / sonorus / Runyon & Hurley" [red label] (MCZ). PARATYPES:MEXICO: CHIHUAHUA: Radiola Spring, tributary Rio Chuhuichupa, 23.vi.1987, Baumann, Kondratieff, Sargent &Wells (1 ♀, BYU). USA: same data as holotype (3 ♀, MTEC); Pima Co., Catalina Mts, Marshall Gulch near Summerhaven, 28.v.1986, J. Jenkins (1 ♂, 2 ♀, MTEC); Santa Cruz Co., Coronado National Forest, Santa Rita Mts, Madera Cyn, 3-4.vi.1991, B.J. Sinclair (1 ♂, 2 ♀, CNC), same as previous, 27.iv.1979, K.N. Barber (1 ♂, DEBU), same as previous, 5100 ft, 25.iv.2001, RLH & JBR (1 ♂, MTEC).