Atomosia affinis Macquart, 1850

Camargo, Alexssandro, Vieira, Rodrigo & Rafael, José Albertino, 2024, Taxonomic review of Aphestia Schiner, 1866 (Diptera: Asilidae: Laphriinae) with description of seven new species, Zootaxa 5436 (1), pp. 1-80 : 72-74

Atomosia affinis Macquart, 1850 stat. rev. et comb. rev.

( Fig. 49 )

Atomosia affinis Macquart, 1850: 379 ( 1851: 75); Williston, 1891: 77 (catalogue); Kertész, 1909: 163 (catalogue); Bromley, 1946: 108 (catalogue); Hull, 1962 (1): 373 (synopsis of world fauna); Martin & Papavero, 1970: 46 (catalogue); Artigas, Papavero & Serra, 1991: 57 (synonymization with Aphestia annulipes ( Macquart, 1838) , Atomosiini catalogue); Papavero, 2009: 85 (catalogue).

Diagnosis. Black; scape almost two times the length of pedicel ( Fig. 49D ); frons white and face whitish pale pruinose ( Fig. 49C–D ); mystacal macrosetae and setae whitish pale ( Fig. 49C–D ); 2 black ocellar setae ( Fig. 49C ); pleuron silvery pruinose, except by an apruinose spot on ventral half of anepisternum ( Fig. 49B ); punctations golden setose; 1 notopleural, 1 supra-alar, 2 postalar ( Fig. 49E ), 8 marginal scutellar ( Fig. 49E ) and 1 black posterior anepisternal macrosetae; anatergite with short, stout and spiniform reddish yellow macrosetae; legs mostly black, tibiae reddish brown with apical third dark brown ( Fig. 49B ); abdominal punctations dark brown setose, except on T1 and T2–5 with a posterior band golden setose ( Fig. 49G ).

Redescription. Holotype female ( Fig. 49 ). Head ( Fig. 49C–D ): white pruinose, except face whitish pale ( Fig. 49C ); orbital setae slightly pale, dark brown dorsally (the most dorsal); frons with convergent slopes; mystacal macrosetae and setae whitish pale ( Fig. 49C–D ); 3 yellowish ocelli, 2 black ocellar setae; vertex deeply excavated with some thin, sparse black setae; 4–5 yellowish postocular macrosetae; occiput black, occipital and lower occipital setae white; proboscis black, proboscial setae whitish and labial yellowish; palpus black, yellowish white setose ( Fig. 49C–D ). Antenna: scape and pedicel black, sparsely white pruinose and black setose, except scape ventrally yellow setose ( Fig. 49C–D ).

Thorax ( Fig. 49A–B, E ): black, scutum with bluish reflections; scutum and scutellum finely punctate; postalar callus dark reddish brown anteriorly; pleuron silvery pruinose, except by an apruinose spot on ventral half of anepisternum ( Fig. 49B ). Chaetotaxy: mostly silvery setose, except scutum and scutellum with punctations golden setose; anepisternum with long and very thin silvery setae dorsally; acrostichal and dorsocentral setae thin, black (slightly longer than golden setae on punctations); macrosetae: antepronotal yellow, 1 notopleural, 1 supra-alar, 2 postalar ( Fig. 49E ), 8 (4 pairs) marginal scutellar (1 reddish yellow on mid left side) ( Fig. 49E ) and 1 posterior anepisternal black; katatergite with long yellow (black dorsally) and anatergite with 6–8 short and stout spiniform reddish yellow macrosetae.

Wings ( Fig. 49F ): translucent, veins reddish brown; vein C until cell m 2; crossvein r-m shortly before half of discal cell; cell r 5 open; cells m 3 and cua closed before wing margin and petiolate; halteres yellow-pale.

Legs ( Fig. 49B ): mostly black except trochanters dark reddish brown; femora with basal and apical extremities reddish; tibiae reddish brown with apical third dark brown; fore and mid tarsi with tarsomeres 1–4 dark reddish, dark brown on hind tarsus; coxae silvery pruinose. Chaetotaxy: coxae with thin silvery setae; trochanters with yellowish white setae; femora yellowish white setose; fore femur with 1 anterodorsal preapical and 2 dorsal black macrosetae; mid femur with 1 anterior yellow, 1 anterodorsal preapical, 2 dorsal and 1 posterodorsal distal black macrosetae; hind femur with a dorsal row of long and thin black setae; 1 anterior reddish yellow and 3–4 ventral yellowish macrosetae; tibiae yellowish white setose with dorsal black, anterior, posterior and ventral reddish yellow macrosetae; tarsi with dorsal black macrosetae, other macrosetae reddish yellow; brush setae reddish yellow; claws black, empodium and pulvilli reddish yellow.

Abdomen ( Fig. 49A–B, G ): black, punctate; T2–5 with a thin silvery pruinose band at posterior margin, thicker laterally ( Fig. 49G ); tergites with, short, thin, appressed dark brown almost black setae on punctations, except on T1 and T2–5 with posterior bands golden setose; tergites laterally with thin black and whitish setae becoming yellowish posteriorly on T6; T1 with 3–4, T2 with 2–3, T3 with 2 and T4 with 1 reddish yellow lateral marginal macrosetae (T5 and T6 without macrosetae); sternites brown with light brown pruinosity and sparse, thin, white setae.

Terminalia ( Fig. 49H ): tergite T9+T10+cercus brown, whitish setose; S8 brown at base and reddish brown on distal half with a conic projection on each corner, each bearing two apical yellowish macrosetae ( Fig. 49H ).

Length. Body: 9.1 mm; wings: 8 mm.

Holotype condition. Postpedicel missing ( Fig. 49A–D ), anepisternum on left side, scutum on right lateral median area and S4–5 on right side damaged.

Male. Unknown.

Distribution. Brazil.

Taxonomic discussion. Macquart (1850) described Atomosia affinis based on a specimen that he believed was a male ( Fig. 49A ). However, with the redescription of the holotype it turned out to be a female. Artigas et al. (1991) synonymized this species under Aphestia annulipes ( Macquart, 1838) without providing any explanation.

The unique similarity this species shares with Aphestia is the presence of mystacal macrosetae on the entire facial extension. Contrastingly, it has more features that are found in Atomosia , such as the presence of dorsocentral setae; and stout and spiniform macrosetae on the anatergite.

The presence of short and stout macrosetae on the anatergite is one of the most remarkable features of Atomosia . In Aphestia , only thin and long setae can be found on the anatergite. One could argue that stout and spiniform macrosetae are also present in Cerotainia Schiner, 1866 and Atoniomyia Hermann, 1912 . However, both have frons with divergent slopes, differing from Atomosia , which has frons with convergent slopes ( Fig. 49C ). Thus, this synonymy cannot be maintained and Atomosia affinis Macquart, 1850 stat. rev. et comb. rev. has herein its status and its previous combination with Atomosia revalidated.

This species is very similar to others in the same genus, such as Atomosia venustula Lynch Arribálzaga, 1880 , which also possesses several marginal scutellar macrosetae and Atomosia dasypus ( Wiedemann, 1828) which also possesses lateral marginal macrosetae on T1–4. Unfortunately, Macquart (1850) mentioned only “ Brésil ” as the type locality making it difficult to trace the exact distribution of this species.

Material examined. Holotype. Atomosia affinis ♂ Macq. n. sp. / Aphestia affinis (Mcq.) N. Papavero det. [19]71 ( Fig. 49A ) (♀ MNHNP).

Figures

FIGURE 49. Atomosia affinis Macquart, 1850 stat. rev. et comb. rev. holotype female. A. Dorsal habitus (insert: labels, not to scale); B. Lateral habitus; C. Head, frontal; D. Same, lateral; E. Scutellum, dorsal; F. Right wing, dorsal; G. Abdomen, dorsal; H. Terminalia, ventral. Abbreviations: r: radial cells; r-m: radial-medial crossvein. Scale bar 1 mm.