Sigalopella, Irwin & Winterton, 2020

Irwin, Michael E. & Winterton, Shaun L., 2020, A new stiletto fly genus from South America (Diptera: Therevidae: Agapophytinae), Zootaxa 4751 (2), pp. 276-290 : 277

Sigalopella gen. n.

(Figs 1–14)

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Type-species: Sigalopella rufifemoralis sp. n. (here designated).

Diagnosis. Predominantly glossy black-bodied flies with long antennae, setal pile longer in male. Body length: 6.5–8.0 mm (male), 7.0– 9.5 mm (female). Head relatively broad, wider than thorax; male eyes contiguous dorsomedially; male with single row of postocular macrosetae dorsally; face distinctively rounded to bulbous laterally, glabrous except for silver pubescence along eye margin, parafacial setae present, more extensive and elongate in male; antenna longer than head; scape narrow elongate, longer than flagellum; flagellum tapered cylindrical; extensive black setal pile along all antennal segments, especially scape and pedicel; palpus incrassate; prosternum without setal pile; metanepisternum without postspiracular setal patch; 1–3 dorsocentral macrosetae; one pair of scutellar macrosetae; posterior lateral surface of midcoxa lacking setal pile; velutum patches absent on femora and gonocoxites; legs with distinct short black setal pile, denser on tibia and tarsi; hind leg relatively longer than fore and mid legs; single anteroventral seta present apically on hind femur; wing mostly uniform dark infuscate, paler posteriorly, cell r 1 hyaline basally; costal vein circumambient around wing margin, wing cell m 3 open, vein R 1 with setae absent; abdominal tergite 2 with setae uniform in size medially; male genitalia with inner gonocoxal process well developed; gonocoxites with medial atrium lacking; hypandrium small; aedeagus with distiphallus narrow apically, dorsal apodeme of parameral sheath broadly triangular, ventral apodeme narrowly forked; female genitalia with acanthophorite setae as two sets (A1 & A2), A1 usually enlarged; three spermathecae present, ducts joining to spermathecal sac duct; spermathecal sac present and simple in shape (not lobed).

Included species. Sigalopella armeniaca sp. n., S. ammophila n. sp., S. nigrofemoralis sp. n. and S. rufifemoralis sp. n.

Etymology. Sigalopella is derived from the Greek sigaloma – smooth, polished, and pellos – dusky, dark, for the dark polished appearance of members of this genus; gender is feminine.

Comments. Sigalopella gen. n. is known only from central Chile (Fig. 14). Pachyrrhiza , Entesia and Mela- nothereva form a monophyletic clade of South American Agapophytinae called the Entesia genus-group (sensu Winterton et al., 2016), which also includes this new genus. We consider Sigalopella gen. n. as the likely sister to Pachyrrhiza . Amongst the South American Agapophytinae , these two genera share characteristics such as a protruding rounded parafacial with parafacial setae present, and the male post-ocular setae elongate and arranged in a single row dorsally. Sigalopella gen. n. can be easily recognised by the overall black coloration, narrow elongate antennae, absence of setal pile on the prosternum and incrassate palpi. Pachyrrhiza has a notably short and bulbous antennal scape (cf. elongate and narrow in Sigalopella gen. n.) and an abundance of macrosetae on the head and scutum. Most Pachyrrhiza have mottled or hyaline wings, never uniformly infuscate like in Sigalopella gen. n. Species of Sigalopella gen. n. are easily separated from each other using external characters such as colour and vestiture, as well as head and antennal shape; male and female genitalia is remarkably uniform amongst all members of the genus and is not useful for differentiating species in either sex.