Achradocera angustifacies Becker, 1922

Quevedo, Lucas, Capellari, Renato S. & Lamas, Carlos José E., 2024, Taxonomic revision of Achradocera Becker (Diptera: Dolichopodidae), with description of two new species, Zootaxa 5519 (3), pp. 301-344 : 304-308

Achradocera angustifacies Becker, 1922 stat. rev.

( Figs 2 , 3 , 26 )

Chrysotus femoratus Bigot, 1890: 295 . Type-locality: Chile. Junior homonym of Chrysotus femoratus Zetterstedt, 1843 . Robinson, 1970: 32 (syn. with C. chilensis ). Syntypes females, OUMNH .

Achradocera angustifacies Becker, 1922: 207 , fig. 78. Type-locality: Quillota, Chile. Lectotype male, MTKD. Bickel, 2000: 16 (syn. with A. barbata ); Runyon, 2020: 102 (syn. with A. apicalis ).

Chrysotus chilensis Van Duzee, 1930: 29 . Type-locality: Concepción , Chile. Type lost, NHMUK. syn. nov.

Chrysotus edwardsi Van Duzee, 1930: 78 . Type-locality: Los Andes , Chile. Holotype male, NHMUK. syn. nov.

Diagnosis (male). Postpedicel longer than arista-like stylus; lower postoccipital setae dense. Legs mostly yellow, except for FIII, dorsal surface of FI and FII, TIII at basal 1/4 and apical 1/5, and distal tarsi, which are all brown infuscated; fore and mid legs simple, hind legs with tarsomeres 3 and 4 concave ventrally. Hypopygium small; surstylus subtriangular, tapered and bearing 1 apical and 1 subapical strong seta; postgonite enlarged and covered by small setae.

Redescription. Male. Body length: 2.6–2.7 mm. Wing: 2.4–2.5 mm long, 0.77–0.85 mm wide. Head. Frons, vertex and face shiny dark green with little coppery pruinosity; narrowest distance between eyes at face almost half width of frons (MSSC); palpus small, yellow, with some black setae (MSSC); proboscis dark brown, with many white hair-like setae; 1 pair of strong, divergent dark brown ocellar setae, and pair of slightly convergent, proclinate and black inner vertical setae, almost half length of ocellars; 1 pair of paravertical setae similar in length to dorsalmost postocular setae and pair of small postocellar setae, half-length of paraverticals; occiput slightly concave above; row of about 8–10 brown postocular setae on dorsal half and many longer white setae ventrally, forming very dense patch of flattened postoccipital setae (MSSC). Antenna black; scape and pedicel short, latter with apical crown of setae; postpedicel truncate on pedicel, basally enlarged, and apically constricted into slender projection, about as long as arista-like stylus (MSSC); arista-like stylus subapical; FAr ratio, 1.0. Thorax. Dorsum shiny dark green with golden and coppery reflections; anepisternum and katepisternum lighter, with thin pruinosity; anepimeron, katatergite and metepimeron grey and thickly covered with pruinosity; about 7 ac pairs of setae; dc with 5 pairs of strong setae; some small and scattered setae anteriad of ac and dc rows; 2–3 white proepisternal setae; 3 intra-alar setae; 2 supraalar setae; 1 intrapostalar seta; 3 postpronotal setae (2 weak and 1 strong); and 2 notopleural setae. Wing. Membrane hyaline, veins brown. Costa ending at M 1 near wing apex (meeting vein M 1); R 1 ending at 2/5 of wing length; lower calypter with fan of about 6 brownish setae; CuAx ratio, 0.51, RMx ratio, 1.48. Legs. Coxae dark brown with little pruinosity, usually stronger on frontal surface of CI; remaining legs mostly yellow, except FIII, dorsal surface of FI and FII, TIII at basal 1/4 and apical 1/5, and distal tarsi all brown infuscated. Leg I. 30, 26, 15, 7, 5, 4, 4. Coxa bearing some small white setae and about 5–7 long black setae apically; T rusty yellow, with distinct apicoventral seta. Leg II. 29, 32, 15, 7, 5, 4, 3. Coxa with strong ad seta at basal half and bearing apical row of 5–7 brown setae; T with 1 anterior strong seta at basal 1/4, 1 anteroventral at middle, and 3 distinct setae apically (1 av, 1 pv and 1 weaker dorsal); t 1–3 with about 4 apicoventral setae circling apex. Leg III. 35, 41, 18, 8, 4, 3, 4. Coxa with strong seta at basal 1/5 and smaller at apical 1/4, both dorsally; T with pd row of 4, ad row of 3, and 4 apical setae (1 v, 1 d, 1 ad and 1 av); t 3–4 concave ventrally (MSSC) ( Fig. 2D ). Abdomen. Metallic green with bronze reflections; about as long as thorax length, broader anteriorly; mostly covered by dark brown setae, except sternites 1 and 2 coated with white setae. Hypopygium ( Fig. 3A–D ). Dark brown with brownish cercus, epandrium circular, phallus with ventral grooves near mid-length, epandrial lobe appressed near base of surstylus and bearing 2–3 setae; surstylus tapered, bearing 1 apical and 1 subapical strong seta. Cercus short and rounded, with setae as figured; postgonite enlarged, covered by small setae, bearing two ventral arms (hypandrium apodeme) and one dorsal projection connected with base of phallus; ejaculatory apodeme digitiform and slightly cambered at middle.

Female. Similar to males, except by MSSC and as noted. Body length: 2.9–3.0 mm. Wing: 2.85–2.92 mm long, 0.9–1.0 mm wide. Terminalia. As in generic description (similar to Fig. 24 ).

Distribution. Chile ( Fig. 26 ).

Type material examined. Achradocera angustifacies : LECTOTYPE [here designated] ♂, labelled: “ Chile | 20.IX.02 | Quillota ”, “ Achradocera angustifacies B. | det. Becker ”, “Typus | Achradocera angustifacies | Beck.”, “ SYNTYPUS | des. U.Kallweit | 1993”, “Coll. W. Schnuse | 1911 - 3” [ MTKD; based on photos].

Chrysotus edwardsi : HOLOTYPE ♂, labelled: “ Chile: | Los Andes | 1–2.i.1927 | F & M Edwards | B M 1927- 63”, “ Chrysotus edwardsi | Holotype Van Duzee”, “ BMNH (E) # 249055”, “ Holotype ”, “ NHMUK010627136 ” [based on photos].

Additional material examined. Chile. 1♂, “ Mittel Chile | Contulmo | Schonemann S. | 8.1.02”, “Zool. Mus. | Berlin”, “ Achradocera chilensis | V.D. 1930b 29”, “ Achradocera sp. | det. Marc Pollet, 2015” [based on photos] ; 4♂, 2♀, “ El Naranjo, Tilama | Coquimbo, Chile | X.1967 | L. E. Peña col.” ; 3♂, 1♀, “ CHILE: Parque Nacional | Fray Jorge—Fog Forest | 30º39’45” S 71º40’57” W | Sweeping, Jan 26, 2011 | D. S. Amorim col.” ; 4♂, “ CHILE: Rio Corel | 35º23′24″ S 71º15′16,4″ W | 314 m —Sweeping | D. S. Amorin col.” ; 8♂, 4♀, “ CHILE: Termas de Sorá | 30º43′55.4″ S 71º29′38.3″ W | Sweeping Jan 25, 2011 | 322 m D. S. Amorim col.” [ MZUSP, except: 2♂, MTEC; 2♂, USNM] .

Remarks. Based only on Becker’s (1922) original description, Bickel (2000) synonymized A. angustifacies stat. rev. with A. barbata (also considered by him as the senior synonym of A. apicalis ). Runyon (2020) examined the types of both A. apicalis and A. barbata and restored the former, assuming A. angustifacies stat. rev. as a junior synonym of A. apicalis , following Bickel (2000). However, after examination of the types of both A. apicalis and A. angustifacies stat. rev. and additional material of both species, it became clear that they are distinct taxa. Achradocera angustifacies stat. rev. differs from A. apicalis by the size of the postpedicel, about as long as arista-like stylus (shorter than arista-like stylus in A. apicalis ), and IIIt 3–4 concave (cylindrical in A. apicalis ). Additionally, A. apicalis is restricted to the Caribbean’s Lesser Antilles, whereas A. angustifacies stat. rev. is known only from Chile.

After examination of photos of the holotype of A. edwardsi (Van Duzee) , we noted that this species and A. angustifacies stat. rev. are very similar to each other, including diagnostic features such as the clearly concave IIIt 3–4, and the same color pattern on TIII and both are hence considered conspecific. In the same work, Van Duzee (1930) described both A. edwardsi (p. 78) and A. chilensis (p. 29). However, the distinction between these species is vague: while A. edwardsi is stated to have a flattened and broad IIIt 5 (plate III, fig. 9), A. chilensis has a slightly broad IIIt 5 (plate I, fig. 2) and Van Duzee’s illustrations of the hind tarsus of both species are very similar. We hence consider both species conspecific with each other and also with A. angustifacies stat. rev. According to the original description ( Van Duzee 1930), the male holotype of A. chilensis from Concepción ( Chile) was housed in the NHMUK, but it could not be located in the museum holdings (D. Sivell, pers. comm.) and is considered to be lost.

Ultimately, Chrysotus femoratus Bigot is a homonym (nec Zetterstedt, 1843) described from a female. Based on Bigot’s description, it looks like Achradocera , especially the femora coloration. Van Duzee (1930: 29) thought it could be a synonym of C. chilensis and Robinson (1970) listed it as such, following ICZN (1999) Arts. 23.3.5 and 60.1. Considering the results presented here, Chile has a single species of Achradocera , therefore, the distribution of C. femoratus suggests that Robinson’s synonymy is correct.

Figures

FIGURE 2. Achradocera angustifacies stat. rev. A. Habitus, left lateral. B. Tarsomeres of leg III. C. Head, left lateral. D. Thorax, dorsal. Scale bars: A, 1 mm; B–D, 0.2 mm.

FIGURE 3. Achradocera angustifacies stat. rev., male genital structures. A. hypopygium, left lateral. B. Hypopygium, ventral. C. Phallus, ejaculatory apodeme and postgonite, right lateral. D. Postgonite, ventral. Scale bar: 0.1 mm.

FIGURE 24. Female genital structures of Achradocera arcuata [similar to genitalia of the other species]. A. dorsal view. B. left lateral view. Abbreviation list: cerc, cercus; T8, tergite 8; T9+10, fusion between tergite 9+10; S8, sternite 8. Scale bar: 0.1 mm.

FIGURE 26. Distribution map of the genus Achradocera.