Epicnemis Borgmeier

Gonzalez, Lisa & Häggqvist, Sibylle, 2020, Revision of the Oriental Region genus Epicnemis Borgmeier (Diptera: Phoridae), Zootaxa 4803 (1), pp. 103-124 : 104-106

Genus Epicnemis Borgmeier

Epicnemis Borgmeier 1962: 172 .

Plethysmochaeta: Beyer 1958: 25–26 .

Type species: Hypocera flavidula Brues 1915 , by original designation.

Genus-level characters. Medium-sized (2–3 mm long), light-brown phorid flies. Males ( Fig. 1a ): Frontal setae reclinate, dorsal fronto-orbital setae absent, thus most species with 4-2-4 frontal setae and one pair of supra-antennal seta (e.g., Fig. 21 ), although first row often not in straight line (e.g., Fig. 23 ). Median furrow absent. Ommatrichia present. Flagellomere 1 yellowish-orange, pyriform; arista dorsal. Palpus large, yellowish-orange, with thick black setae apically and thinner, shorter black setulae ventrally. Postpronotal lobes large, spiracle nearly dorsal ( Fig. 34 ). Posterior margin of anepisternum darkened. Parapsidal suture (between scutum and anepisternum) short, not extending anteriorly to spiracle. Anepisternum setulose dorsally. Notopleuron with 3 large setae. Anepimeron reduced, meron expanded, concave. Halter short. Costal setae short; wing vein R2+3 absent. Midtibia with setal palisade extending to midlength. Hind tibia with several scattered medium-sized anterodorsal setae and complete dorsal setal palisade. Eversible membrane bearing field of dense thickened setulae present in between tergite 1 and 2 ( Figs. 39 –40); smaller such fields present more posteriorly. Hypandrium greatly reduced.

Females: apterous, limuloid ( Fig. 1b ).

Previously described species. E. flavidula (Brues) , E. testis Borgmeier , E. harveyi Disney , E. linguiformis Chu & Liu , E. namkyensis Mostovski.

Species recognition. The most distinctive characters for these flies are found in the male genitalia and the frons. Most species are recognizable easily by observing these two features. The genitalia are often withdrawn into the abdomen, however, making dissection a frequent necessity.

Setation of the frons and of the legs is often used in phorid taxonomy, but in Epicnemis the patterns of setae are notably varied and less reliable. The species with larger numbers of specimens invariably include those with extra frontal setae, or in one case (an atypical male of E. alus new species), lacking usual frontal setae. Tibial setae are similarly varied in individual specimens.

Way of life. With their limuoid female body forms, these flies presumably live in the nests of termites. Surprisingly, there is no specific information on hosts or lifestyles. Their larvae might be predators, scavengers, or parasitoids.

Distribution. Oriental Region ( Figure 2 ). This genus conforms well to Wallace’s Line ( Wallace 1876), with species being apparently absent from Sulawesi (at least not reported by Disney 1985). Russell Cox (personal communication) has reported specimens from Timor, however, which is east of the southern extremity of Wallace’s line.

Derivation of name. The name seems to be based on the presence of mid- and hind tibial setal palisades (epi - upon, kneme - knee), a character that Borgmeier stressed in his original description.

Figures

FIGURES 1A–B. Habitus, Epicnemis species. a. E. ratanae new species, male. b. Epicnemis species, female.

FIGURE 2. Known distribution of Epicnemis species.

FIGURES 18–23. Heads, Epicnemis species, males, anterior view.

FIGURES 30–35. Epicnemis species, males. Figs. 30–33. Heads, anterior view. Fig. 34. Anterior part of thorax, lateral. Fig. 35. Male terminalia, left lateral. Abbreviation: sp, spiracle.

FIGURES 36–39. Epicnemis species. Figs. 36–37. Male terminalia, left lateral. Fig. 36. Air dried. Fig. 37. HMDS dried. Figs. 38–39. Posterior part of thorax and anterior segments of male abdomen, dorsal. Fig. 38. habitus. Fig. 39. detail of spinuli. Abbreviation: T1, T2—abdominal tergite 1, 2.