Neoscutops Malloch

Ale-Rocha, Rosaly & Freitas, Geovânia, 2011, Revision of the Neotropical genus Neoscutops Malloch (Diptera: Periscelididae), Zootaxa 3016, pp. 1-28 : 2-3

Neoscutops Malloch

Neoscutops Malloch, 1926: 25 ; Prado, 1975: 1 [catalog]; Amorim & Vasconcelos, 1990: 37 -39 [fauna, Brazil]. Type species: N. rotundipennis Malloch , by original designation.

Diagnosis. This genus can be distinguished from other members of Periscelididae by the following combination of characters: face convex, shiny and setose; arista bipectinate; ocellar triangle setulose, ocellar pair weakly developed; postocellar setae divergent and short; medial and lateral vertical setae well developed; 1 fronto-orbital and 1 dorsocentral prescutellar setae; mid tibia with 1 apicoventral spine; wing slightly to strongly infuscate, lacking pale areas; R1 with setae on dorsal surface; R2+3 long, curved anteriorly toward costal margin, extending very close to Costa just beyond R1; M1 arched; bm-cu incomplete; base of CuA2 incomplete or indistinct; A1+CuA2 not reaching wing margin.

Redescription. Body length: 1.3 – 3.6 mm. Head. Frons with margins parallel to slightly divergent dorsally; face slightly convex, wide, shiny, haired on distal 2/3, lower facial margin convex or concave; parafacial and fronto-orbital plate setulose. Mouth opening large; palpus flat, short and clavate or long and quite rectangular; clypeus shiny, U-shaped or a roundish convex sclerite. Antenna: scape vey short; pedicel cap-like with dorsal cleft; first flagellomere oval; arista bipectinate with dorsal and ventral rays decreasing progressively in length toward apex. Medial and lateral vertical setae well developed; one pair of orbital seta; postocellar setae divergent; ocellar triangle setulose, ocellar seta short and slightly robust, sometimes inconspicuous. Thorax robust, approximately as wide as long; subscutellum conspicuously protuberant; scutum covered by short setae, scutellum with sparse microtomentum; 1 postpronotal, 2 notopleural, 1 postsutural supra-alar, 1 postalar, 1 dorsocentral prescutellar, 1 or 2 katepisternal and 1 or 2 pairs of scutellar setae. Wing infuscate, lacking pale areas; subcosta incomplete; R1 with setulae on dorsal surface; R2+3 long, curved anteriorly toward costal margin, extending very close to Costa just beyond R1 and reaching margin at approximately distal 1/5 of the wing; M1 arched, evanescent toward margin of wing; M1 and CuA1 reaching wing margin or evanescent close to margin; CuA2 incomplete or indistinct; A1+CuA2 not reaching wing margin; the longitudinal fold crosses the dm cell longitudinally. Legs robust; mid tibia with one black apicoventral spine; mid tarsus with small black apical spines on ventral surface. Abdomen rather broad, short and dorsoventrally flattened, covered by short setae and sparse microtomentum. Tergite 1+2 long, approximately 1/ 3 length of abdomen, with a longitudinal median unsclerotized line from base to middle of sclerite. Male terminalia: symmetrical; tergite and sternite 6 well developed, free; pregenital sclerite (syntergosternite 7+8) reduced to a dorsolateral narrow stripe, free from tergite 6 or fused with lateral margin of tergite 6, and including 7th spiracle; epandrium convex; surstylus distinct or undifferentiated; postgonites articulated at anterior margin of hypandrium, partly encircling base of phallus; cercus developed, usually large and setose, sometimes membranous and reduced; phallus ribbon-like; genital pouch (hypandrium + adeagal apodeme) large, inflated, slightly sclerotized, forming a bursa-like chamber containing the phallus. Female terminalia: tergite and sternite 7 fused, forming a ring; tergite and sternite 8 free; sternite 8 broad; tergite 8 narrow; cercus usually small, ovate.

Remarks. Neoscutops is composed of two monophyletic species groups (see phylogenetic analysis).

The Periscelidinae are believed to be a well-established monophyletic assemblage ( Griffiths 1972). The putative synapomorphies of Periscelidinae in the external morphology, which include a large mouth opening, 1 frontoorbital seta, costal vein extending to R4+5, and occiput with a silvery-white microtomentose area adjacent to the posterior margin of the compound eye ( Griffiths 1972; Mathis & Rung 2004), are shared by Neoscutops . Our study has revealed that the species of Neoscutops also share the synapomorphies in the male and female terminalia pointed out by Griffiths (1972) as synapomorphic for the Periscelidinae: 7th abdominal tergite and sternite fused in the female, forming a ring which includes the 7th spiracle; syntergosternite 7+8 of the male extending ventrally on either side, including both the 7th spiracle, and a slender and ribbon-like phallus, supported by a broad strip of flexible sclerotization..

Geographical distribution. Neotropical Region ( Brazil, Costa Rica, Ecuador, Peru).