Hurleyella Runyon & Robinson, 2010

Runyon, Justin B., 2019, Two new species of Hurleyella Runyon & Robinson (Diptera: Dolichopodidae), with the first record from the Neotropics, Zootaxa 4568 (3), pp. 548-560 : 549-550

Genus Hurleyella Runyon & Robinson

Hurleyella Runyon & Robinson, 2010: 58 . Type-species: Hurleyella cumberlandensis Runyon & Robinson , by original designation.

Recognition. The combination of the following character states will diagnose Hurleyella in the Nearctic and Neotropics: Body length approximately 1.0 mm or less. Vertex of head not excavate. Antennal scape without dorsal setae; pedicel without medioapical thumb-like projection. Eyes with short ommatrichia between facets. Palpi not enlarged. Proepisternum with at most a few small hairs; acrostichal setae absent; posterior mesonotum distinctly flattened and slightly depressed. Legs without major setae; femora without preapical setae; legs of males unmodified, lacking male secondary sexual characters. Wing (as in Figs 3, 4 ) hyaline, with costa continuous to tip of vein M 1; vein R 2+3 characteristically 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. Hypopygium without ventral projections asymmetrically from one side.

Remarks. The distinctive wing venation of Hurleyella , with a short vein R 2+3 and veins R 4+5 and M 1 converging and nearly parallel near wing apex (as in Figs 3, 4 ), will separate this genus from others except Microchrysotus and Micromedetera ( Robinson 1964b, 1975). Very few other examples of such a short vein R 2+3 are documented in the Dolichopodidae . A very short vein R 2+3 occurs in males of Australachalcus edwardsae (Van Duzee) and Tachytrechus alatus (Becker) , but this vein is of normal length in the females ( Pollet 2005; Brooks & Cumming 2008). Runyon & Robinson (2010) reported occurrence of a short vein R 2+ 3 in Enlina atrata (Van Duzee) (as Achalcus atratus ), based on the original description by Van Duzee (1930) (“First vein very short”, p. 24), but examination of the holotype of E. atrata (see Runyon & Pollet 2018) revealed that R 2+3 is of normal length and Van Duzee was referring to vein R 1 as the “first vein”.

In the Manual of Central America Diptera ( Bickel 2009) , Hurleyella keys to Micromedetera , to which it seems most closely related, but the hypopygium of Hurleyella is distinct from that of Micromedetera which has ventral projections asymmetrically from one side ( Robinson 1975, figs 71, 75, 77). At present, it is not possible to separate females of Hurleyella and Micromedetera . Habitat might also differ between these genera with Hurleyella occurring in relatively drier environments than Micromedetera (see Discussion). Hurleyella also appears to be related to Microchrysotus , but males of Hurleyella lack enlarged palpi, modified fore tarsi, and a median darkened wing band found in males of Microchrysotus ( Robinson 1964b) . Females of Microchrysotus also have a darkened wing band, which distinguishes them from females of Hurleyella and Micromedetera .

Figures

FIGURES 3–4. Photographs of male wings. 3. Hurleyella belizensis sp. nov.; 4. Hurleyella salina sp. nov. Scale bars = 0.5 mm.