Neoscutops rungae, Carvalho-Filho & Barbosa & Viana, 2022

Carvalho-Filho, Fernando S., Barbosa, Rodrigo R. & Viana, Talita C., 2022, A new species of Neoscutops Malloch (Diptera: Periscelididae) reared from an ant nest, Zootaxa 5125 (4), pp. 445-450 : 446-447

Neoscutops rungae sp. nov.

( Figs. 2–10 )

Diagnosis. Frons and face shiny dark brown ( Fig. 3 ); apical portion of subcostal, r 1, r 2+3, r 4+5 cells hyaline ( Fig. 2 ); surstylus bearing a basal rounded projection on the inner margin, clavate in lateral view ( Fig. 6 ); sternite 8 of female with a shallow median cleft on posterior margin with region around cleft more heavily sclerotized ( Fig. 10 ).

Description. Holotype male. Body: 1.5 mm. Wing: 1.2 mm. Head ( Fig. 3 ). Frons and face shiny dark brown. Face with fine yellow setae. Parafacial dark brown. Gena dark brown, with short yellow setae. Antenna yellowish brown; pedicel with few short light brown setae; first flagellomere elliptical; arista sub-basal dorsal, yellow basally and dark brown distally, with 6 dorsal and 3 ventral brown rays. Mouthparts: proboscis dark brown; palpus yellow, short, clavate, with rounded apex and fine brown setae; clypeus dark brown. Postcranium dark brown, paler on lateral margin, with a band of dense whitish microtomentum on lateral margin of eye, and fine brown setae on lateral margin and postgena. Eyes with very short and fine, sparse, pale interfacetal setae. Chaetotaxy: 1 lateral vertical and 1 medial vertical pairs long but medial pair twice as long as lateral pair; 1 orbital pair inserted below middle of frons, as long as lateral vertical pair; 1 short, divergent postocellar pair; 1 ocellar pair directed downward, convergent, fine, elongate, longer than postocellar pair, inserted laterally on ocellar triangle; all setae pale brown.

Thorax. Shiny dark brown, with pale brown microtomentum on notopleuron and mesopleuron, except on anepisternum and katepisternum. Scutum with short light brown setulae. Chaetotaxy: 1 postpronotal; 2 notopleural; 1 post-sutural supra-alar; 1 post-alar; 1 dorsocentral prescutellar very long; katepisternum with 2 developed setae on upper margin and a few more short setulae on lower margin; 2 scutellar pairs as long as dorsocentral prescutellar, apical pair convergent; all setae light brown.

Legs ( Figs. 4–5 ). Predominantly brown, apexes of tibiae and tarsi yellowish. Fore femur with long and fine setae on postero-ventral surface; mid tarsus with small ventral apical brown spines on tarsomeres 1 to 3.

Wing ( Fig. 2 ). Membrane mostly infuscate, more or less evenly gray, with apical portion of subcostal, r 1, r 2+3, r 4+5 cells hyaline; veins mostly dark brown, except yellowish distal portion of R 1, R 2+3, R 4+5 and M; the longitudinal fold crosses the vein dm-cu above the middle.

Abdomen. Dark brown, covered with short, thin and yellow setae. Sternite 6 wider than long, with long setae restricted to lateral portion and posterior margin and with a cluster of median tiny setae on posterior margin ( Fig. 8 ). Terminalia ( Figs. 6, 7, 9 ). Epandrium higher than wide in lateral view, with long setae; cercus short and rounded, pigmented, widely separated and with many elongate fine setae. Surstylus articulated with epandrium, elongate and narrowed, with rounded convergent tips, bearing a basal rounded projection in the inner margin; clavate in lateral view; with some scattered tiny pointed setae on ventral surface. Phallus short and slender. Postgonite short and triangular, with upcurved tip. Ejaculatory apodeme clavate. Phallopoderme widened and rounded in lateral view. Hypandrium triangular.

Female. As in the male. Terminalia ( Fig. 10 ). Syntergosternite 7 well sclerotized and narrowed, with many long setae. Tergite 8 narrowed, with a row of setae on posterior margin. Sternite 8 well-developed, widened posteriorly, with a shallow median cleft on posterior margin, region around cleft strongly sclerotized; covered with many scattered long setae. Epiproct narrowed and widened, with a row of setae on posterior margin. Hypoproct small, wider than long, widened posteriorly, with setae restricted to posterior margin. Cercus small and rounded, with some long setae.

Type material. Holotype ♂ ( MPEG): Belém, PA [= state of Pará], Brasil [= Brazil] / Campus MPEG [Research Campus of MPEG] / mata secundária [secondary forest] / 06.VII.2021 / F. Carvalho-Filho & R. Barbosa // Criado de ninho de [= reared from] / Azteca aff. chartifex .

Paratypes 1 ♂ and 1 ♀ ( MPEG). Same data as holotype .

Distribution. Brazil (Pará).

Etymology. Named in honor of Dr. Alessandra Rung (California Department of Food & Agriculture), an eminent Brazilian entomologist who has worked on periscelidid taxonomy.

Remarks. According to the key and definition provided by Ale-Rocha & Freitas (2011), the new species belongs to the rotundipennis species-group, which comprises four valid species: N. cariri Amorim & Vasconcelos , N. minor Ale-Rocha & Freitas , N. ranyseae Ale-Rocha & Freitas , and N. rotundipennis Malloch. Neoscutops rungae sp. nov. differs from all the other species of this species group in having face fully dark brown ( Fig. 3 ); surstylus with a basal rounded projection on inner margin ( Fig. 6 ) and in the shape of female sternite 8 ( Fig. 10 ). The surstylus of N. minor also has a rounded projection, but it is preapical (fig. 41 in Ale-Rocha & Freitas (2011)).

Neoscutops rungae sp. nov. shares with N. cariri Amorim & Vasconcelos a predominately dark brown face, but in N. cariri it has an inverted W-shaped light yellow mark. We were not able to obtain information about the terminalia of N. cariri , since there are no figures of it in the original description and the type specimens were lost in the 2018 fire of Museu Nacional do Rio de Janeiro (MNRJ), where they were deposited ( Amorim & Vasconcelos 1990).

Notes on natural history. All the three examined specimens of N. rungae sp. nov. analyzed were reared from a carton nest of Azteca aff. chartifex . Periscelididae is composed of 11 genera, but the larval breeding substrate is only known from only two genera ( Periscelis Loew and Stenomicra Coquillett ). The larvae of Periscelis species have been found associated with sap from bleeding deciduous trees (oak, elm, cottonwood, etc.) and the larvae of Stenomicra have been found in phytotelma and flowers of several plant species of the families Apiaceae , Araceae, Bromeliacea , Liliaceae , Pandanaceae , and Poaceae ( Williams 1939; Papp 1998; Campos et al. 2010; Mathis & Rungs 2010, 2011; Gomes et al. 2018). Therefore, this is the first record on the feeding substrate of the larvae of Neoscutops and the first record of a periscelidid associated with an ant nest.

Many species of true flies are associated with carton nests of Azteca ants, mainly from the families Phoridae and Milichiidae ( Brown 2010; Swann 2010). Some species of these families are parasitoids or predators of adult or brood or they are saprophagous, feeding on the microorganisms that grow in the walls of ant nest ( Brown 2010; Swann 2010; Pérez-Lachaud et al. 2017). Based on what is known about the natural history of the larvae of the other genera of periscelidids, we believe that the larvae of the new described species of Neoscutops are saprophagous in the ant nest.

The adults of N. rungae sp. nov. resemble a small black lady beetle ( Coccinellidae ) in body form and locomotory behavior. Live specimens have a truncate and rounded body, helping to increase the lady beetle resemblance. They also have a short and shaded wing, which is maintained compressed against the body, concealing it. This resemblance appears to function primarily in Batesian mimicry, since the flies probably are unarmed while coccinellids are avoided by predators, because they have glands that releases substances with unpleasant properties ( King & Meinwald 1996).

Figures

FIGURES 1–5. 1. Carton nest of Azteca aff. chartifex Forel (Formicidae: Dolichoderinae). 2–5. Neoscutops rungae sp. nov. 2. Wing (paratype), dorsal view. 3. Head (paratype), anterior view. 4. Habitus (paratype), lateral view. 5. Habitus (holotype), lateral view. Scale bars: 2, 3 = 0.2 mm; 4, 5 = 0.5 mm.

FIGURES 6–10. Neoscutops rungae sp. nov. 6–9. Male (paratype): 6. Cercus, epandrium and surstylus, posterior view, arrow showing rounded projection on the inner margin of surstylus (setation omitted on the left side). 7. Entire terminalia, lateral view. 8. Sternite 6, ventral view (setation omitted on the left side). 9. Postgonite and phallapodeme, posterior view. 10. Female terminalia (paratype), posteroventral view (setation omitted on the left side). Abbreviations: cerc = cercus; ej apod = ejacula- tory apodeme; ep = epandrium; epp = epiproct, hyp = hypoproct; hypd = hypandrium; ph = phallus; pha = phallapodeme; pg = postgonite; ST = sternite; TG = tergite. Scale bars: 10 µm.