Hurleyella Runyon & Robinson, 2010

Runyon, Justin B. & Robinson, Harold, 2010, Hurleyella, a new genus of Nearctic Dolichopodidae (Diptera), Zootaxa 2400 (1), pp. 57-65 : 58-60

Genus Hurleyella Runyon & Robinson , gen. nov.

Type species: Hurleyella cumberlandensis new species. Habitus ( Fig. 1).

Diagnosis. The combination of the following character states will diagnose Hurleyella in the Nearctic. Minute size, body length approximately 1.0 mm. Vertex of head not excavate. Antennal scape without dorsal setae; pedicel without medioapical thumb-like projection. Eyes with short hairs between facets. Wing with costa continuous to tip of unbranched vein M; vein R 2+3 short, fusing with costa about half way between termination of R 1 and R 4+5; veins R 4+5 and M 1 converging near wing apex, then nearly parallel at apex; crossvein dm-cu shorter than last part of CuA 1. Proepisternum with at most a few, small hairs. Femora without preapical setae.

In Nearctic keys ( Robinson 1964a; Robinson & Vockeroth 1981), Hurleyella runs to Xanthochlorus Loew , but is easily distinguished by its minute size, dark body color, apical arista, and short wing vein R 2+3.

In the Neotropics, Hurleyella is only likely to be confused with Microcyrtura , Microchrysotus , or Micromedetera , which also have the short wing vein R 2+3. Microcyrtura is distinguished from Hurleyella by the nearly straight preabdomen bearing a sharply reflexed gentital capsule in the male and by the very long arista; Microchrysotus has ornamented palpi and fore tarsi and a banded wing. The wing venation and curved abdomen of Hurleyella are very much like Micromedetera , but the hypopygium of Hurleyella is symmetrical and lacks the distinct projections asymmetrically from one side found in Micromedetera . On the basis of its wing venation, Hurleyella keys in the Manual of Central American Diptera ( Bickel 2009) to Micromedetera with which it is considered to be most closely related.

Description. Male: Head: face pollinose, with dorsal half broadly triangular, ventral half narrowed with sides nearly parallel to slightly broadened at palpus; frontoclypeal suture distinct ( Fig. 2A ). Dorsal postcranium strongly concave ( Fig. 1). Eyes ( Figs. 2A, C ) with short hairs between facets; ommatidia enlarged near face. Vertical setae not on elevation or tubercle; ocellar tubercle not prominent; postocellar setae very short, hair-like; postocular setae very short, sparse ( Fig. 2A ). Ventral postcranial hairs (beard) and gena absent. Palpus ( Fig. 2A ) small, not ornamented. Proboscis sclerotized, shining, not or slightly enlarged. Labellum with 6 sclerotized pseudotracheae, but not geminately so. Antenna ( Figs. 2A, B ) short, scape without dorsal setae; pedicel with apical ring of setulae; arista apical, about as long as height of face.

Thorax: scutum with posterior third distinctly flattened. 4 or 5 dorsocentral setae; acrostichal setae absent; 1 notopleural seta; 1 scutellar seta per side, no additional hairs; 1 humeral seta.

Legs: not ornamented, without major setae. Coxa II without lateral seta. Coxa III with minute lateral hair. Femora without preapical setae.

Wing ( Fig. 3 ): vein R 2+3 short, fusing with costa about half way between termination of R 1 and R 4+5. Basal section of M 1 curving posteriorly to crossvein dm-cu, remainder nearly straight, directed slightly anteriorly. Vein R 4+5 curving toward, then nearly parallel to M 1 just before wing apex. Vein M without evident bosse alaire, the slight flexion and wing indentation typically on vein M distal to crossvein dm-cu that is present in many dolichopodids. Vein A 1 absent. Calypter without evident setae.

Abdomen: cylindrical, gradually but only slightly tapering ( Figs. 1, 4A ). Hypopygium ( Figs. 1, 4–5 ) bulbous, borne on a broad peduncle formed by abdominal segment 7; abdominal tergite 7 setose; epandrium deeply emarginate dorsally, with basal lobes bearing setae; abdominal sternite 8 with setae; hypopygial foramen left basal; hypandrium fused to base of epandrium, divided into 2 asymmetrical lobes; surstylus large, complex and only partially attached to epandrium, with many lobes, several blade-like setae, and pair of long lateroapical membranous flanges; phallus simple, abruptly arched and projecting ventrally.

Female: Similar to male. Abdominal terminalia with approximately 6 acanthophorite spines.

Etymology: Hurleyella is named in honor of the late dipterist Richard Hurley (1934–2008). The Latin diminutive -ella denotes the small body size of this genus.

Remarks: Because only two species are known, the division of generic and specific characters is rather arbitrary, but we have attempted to include the usual characters known to be of value for other dolichopodid genera, or those characters anticipated to be constant in Hurleyella .

Figures

FIGURE 2. Hurleyella cumberlandensis, head. A. head, front coxae and thorax ca. anterolateral view; B. antenna, medial view; C. close-up of ommatidia showing hairs between facets. Abbreviation: cx—front coxae.

FIGURE 3. Hurleyella cumberlandensis, male wing.

FIGURE 4. Hurleyella cumberlandensis. A. abdomen and hypopygium, left lateral view; B. hypopygium, left dorsolateral view; C. hypopygium, dorsal view. Abbreviations: epd - epandrium, fsur - lateroapical flange of surstylus, S8 - abdominal sternite 8, T7 - abdominal tergite 7.