Hydropeza, Sinclair, 1999

Sinclair, Bradley J., 2016, Revision of the Australian species of Hydropeza Sinclair (Diptera: Empididae: Ragadinae subfam. nov.), Records of the Australian Museum 68 (1), pp. 1-22 : 3-4

Key to Australian species of Hydropeza

Most females from Queensland are not readily identifiable due to similar terminalia and uncertainty concerning variation. More study on positively associated females from Queensland is required.

1 Wings reduced to halter-like appendages; head and body chaetotaxy greatly reduced and slender; eyes closely approximated below antennae ( Figs 1 , 3 ) .................................................................. H. aptera sp. nov.

—— Wings fully developed; head and body chaetotaxy very long and bristle-like ( Figs 4–6 ); eyes widely separated below antennae ................................................. 2

2 Acrostichal setae present posterior to first pair of dorsocentral setae (females not readily distinguishable in the following species) .............................................. 3

—— Acrostichal setae confined anteriorly to first pair of dorsocentral setae ........................................................................................................................................... 5

3 Male cercus unforked; phallus inflated with highly modified apex comprised of lobes and jagged edges ( Fig. 24 ); female abdominal segment 8 distinctly swollen ....................................................................... H. intricata sp. nov.

—— Male cercus forked; phallus flattened with simple apex; female segment 8 not swollen ............................................................................................................... 4

4 Male cercus U-shaped; upper branch straight with apex rounded ( Fig. 23 ) .................................................................................................... H. divaricata sp. nov.

—— Male cercus V-shaped; upper branch slightly twisted with narrow apex ( Fig. 12 ) ............................................................................................... H. curvata sp. nov.

5 Arista-like stylus subequal to or longer than length of postpedicel; male hind femur swollen, wider than mid femur (as in Fig. 4 ), slender in female; hind tarsomere 4 unmodified in both sexes, not laterally compressed ................................................................................................. 6

—— Arista-like stylus shorter than length of postpedicel; hind femur slender in both sexes, not broader than other femora ( Figs 5, 6 ); hind tarsomere 4 laterally compressed in both sexes, with ventral keel ........................................................................................................................ 8

6 Disc of scutellum with numerous long setulae; male cercus Y-shaped, apex of surstylus with straight spine-like projection; postgonite digitiform, erect and extending beyond margin of epandrium ( Fig. 25 ) ........................................................................ H. queenslandensis sp. nov.

—— Disc of scutellum with at most 1–2 pairs of long setulae; male terminalia otherwise .................................................................................................................. 7

7 Arista-like stylus 2.5 times length of postpedicel; male cercus unforked, lying horizontally on epandrium, apex bent medially at right angle; apex of surstylus strongly rounded with stout setae on inner face; postgonite short, broad and truncate ( Fig. 9 ) ....................... H. angulata sp. nov.

—— Arista-like stylus only slightly longer than postpedicel; male cercus antler-like, lower branch shorter than upper; apex of surstylus strongly hooked and arched anteromedially; postgonite sickle-shaped and hooked ( Fig. 11 ) .............................................................. H. cornuta sp. nov.

8 Large species, wing at least 6 mm long ( Fig. 5 ); face with row of long setulae on inner margin of eye ( Fig. 13 ); scutellum with setae confined to margin; male foreleg with tarsomere 1 unmodified; male mid femur modified with knob-like ventral process ( Fig. 15 ) ....................................................................................... H. tasmanica sp. nov.

—— Smaller species, wing less than 4 mm long ( Fig. 6 ); face lacking setulae; scutellum with setulae dorsally on disc; male foreleg modified with claw-like process on tarsomere 1 ( Fig. 18 ); male mid femur without knob-like ventral process ............................................ H. unguicula sp. nov.

Figures

Figures 1–2. (1) Hydropeza aptera (drawn by Hannah Finlay). (2) McPartlan Pass, Tasmania, type-locality of H. aptera (photograph: M. Driessen). Scale bar = 0.5 mm.

Figures 3–6. Habitus images of dried mounted male species of Hydropeza, lateral view. (3) H. aptera. (4) H. intricata. (5) H. tasmanica. (6) H. unguicula. Scale bars = 1.0 mm, except Fig. 3 where scale bar = 0.5 mm.

Figures 23–25. Male terminalia of Hydropeza, lateral view. (23) H. divaricata. (24) H.intricata. (25) H. queenslandensis.Abbreviations:cerc, cercus; ph, phallus; pgt, postgonite; sur, surstylus. Scale bars = 0.1 mm.

Figures 9–12. Male terminalia of Hydropeza, lateral view. (9) H. angulata (inset showing inner apex of cercus). (10) H. aptera. (11) H. cornuta. (12) H. curvata. Abbreviations: cerc, cercus; ej apod, ejaculatory apodeme; goncx apod, gonocoxal apodeme; pgt, postgonite; ph, phallus; sur, surstylus. Scale bars = 0.1 mm.

Figures 13–18. Scanning electron photographs of Hydropeza tasmanica and digital image of foreleg of H. unguicula. (13) Head (scale bar = 0.5 mm) (from Sinclair & McLellan, 2004, fig. 10). (14) Fore coxae (scale bar = 0.2 mm). (15) Male mid femur (scale bar = 0.1 mm). (16) Male mid femur and tibia (scale bar = 0.5 mm). (17) Tarsomere 5 and acropod (scale bar = 0.2 mm). (18) Male forelegs of H. unguicula (scale bar = 1.0 mm).