Phoomyia Naglis & Grootaert

Naglis, Stefan, Grootaert, Patrick & Brooks, Scott E., 2013, Phoomyia, a new genus of Dolichopodinae from the Oriental Region (Diptera: Dolichopodidae), Zootaxa 3666 (1), pp. 93-99 : 94-97

Phoomyia Naglis & Grootaert gen. nov.

Type species: Phoomyia srilankensis Naglis & Brooks sp. nov.

Diagnosis. Phoomyia is distinguished from other genera of Dolichopodidae by the following combination of characters: body non-metallic, head and thorax grey, abdomen mostly yellow or brown with grey pruinosity (Fig. 3A); frons and face broad in both sexes; scape with dorsal hairs; vein M beyond crossvein dm-cu with strong anterior bend, strongly convergent with R4+5 (Fig. 3B); hind tibia of males with bifurcate posteroapical projection (Fig. 3C); hind basitarsus with 1 strong dorsal seta (Fig. 3C); male cercus extremely reduced ( Figs 1 A, 1B, 2A, 2B); female terminalia with tergite 10 undivided and acutely V-shaped with acanthophorite spine-like setae encircling apex ( Fig. 1 E).

Description. Body length 2.0– 3.5 mm, non-metallic flies with dense grey pruinosity, legs yellow (Fig. 3A). Head: Face broad; eyes distinctly separated, almost parallel-sided in males and females; frons broad; scape with dorsal hairs; first flagellomere subovate, about as long as basal height; arista dorsal to apicodorsal; occiput concave; postvertical setae present. Thorax: 6 pairs dorsocentral setae, fifth pair strongly offset medially; acrostichal setae biseriate; 1 pair strong scutellar setae, and 1 hair-like seta laterad. Legs: Hind coxa with 1 strong lateral seta; mid and hind femur with strong ad preapical seta; male hind tibia with bifurcate posteroapical projection (MSSC) (Fig. 3C); hind basitarsus (Fig. 3C) with 1 strong dorsal seta; claws and pulvilli simple. Wing (Fig. 3B): Vein R4+5 curved posteriad in distal part; vein M with distinct bend at 1/2 beyond crossvein dm-cu, converging towards R4+5, joining costa anteriad of wing apex. Abdomen: Male: hypopygium ( Figs 1 A-D, 2A, 2B) with epandrium distinctly longer than high; epandrial lobes weakly developed or absent; ventral lobe of surstylus shorter than dorsal lobe; postgonite with short blunt apex; hypandrium narrow; phallus slender; cercus very reduced, not longer than surstylus. Female: terminalia ( Figs 1 E, 1F) with sternite 8 lacking rod-like apicolateral projections; tergite 10 undivided, acutely V-shaped in dorsal view with acanthophorite spine-like setae encircling apex.

Etymology. The name is composed of the Thai word Phoo which means crab, and myia from the Greek for fly. Adults of the new genus are often found inside the entrance burrows of ghost crabs ( Ocypode Weber ) on sandy beaches. The gender is feminine.

Remarks. Phoomyia is most closely related to Argyrochlamys and Pseudargyrochlamys , sharing non-metallic body coloration and female terminalia with tergite 10 undivided and acutely V-shaped with acanthophorite spinelike setae encircling apex ( Figs 1 E, 1F). In other female dolichopodines, tergite 10 is divided medially into broad hemitergites each bearing a transverse row of acanthophorite spine-like setae (see figures in Brooks 2005). Females of Phoomyia lack the distinctive rod-like apicolateral projections of tergite 8 that are present in species of Argyrochlamys (see Brooks 2005, figs 6D, 6E, 7D, 7E). We have also observed these rod-like projections in an undescribed species of Pseudargyrochlamys from South Africa (Grichanov, unpublished photograph); however, their presence in the other species of this genus remains to be confirmed. The three genera can be distinguished from each other and the remaining Dolichopodinae in the key provided below.

Phoomyia srilankensis Naglis & Brooks sp. nov. ( Fig. 1 )

Type material. HOLOTYPE 3: SRI LANKA: S. Prov., Kosgoda, 44 mls SSE Colombo, 25.I.62, Loc. 21, swept on herbs on sandy beach (ZMLU). PARATYPES: SRI LANKA: 3Ƥ: same data as holotype; 23: E. Prov., Kuchchaveli, 20 mls NW Trincomalee, 9–10.II.1962, Loc. 60, swept on herbs on sandy beach; 1 3: W. Prov., Ratmalana, 9 mls S Colombo, 7–13.I.1962, Loc. 6, swept on dry grassland; 2 Ƥ: N. Prov., 2 mls W Point Pedro, 13.II.1962, Loc. 69, swept on herbs on sandy beach (all ZMLU).

Description. Male. Length (holotype): body 2.2 mm, wing 2.3 mm. All setae whitish yellow except as noted. Head: Face broad, at narrowest part 2.5 times as wide as distance between ocellar setae, with dense silvery-white pruinosity; clypeus rounded apically, not projecting beyond lower eye margin; palp short, yellow; antennal segments yellow, with yellow setae, apical segment of arista black; scape with dorsal hairs, about as long as pedicel; pedicel short, with apical ring of short setulae; first flagellomere ovate, rounded apically, as long as high; arista dorsal to dorsoapical, bare, 2.5 times as long as first flagellomere, first segment short, second segment 6 times longer than first segment; frons broad, with dense grey pruinosity; pair of strong vertical setae on level of ocellar setae; pair of strong ocellar setae, as long as vertical setae; pair of strong postvertical setae; postocular setae uniseriate. Thorax: Mesonotum and scutellum covered with dense grey pruinosity; 6 pairs of strong dorsocentral setae, fifth pair offset medially; 7 pairs of acrostichal setae; scutellum with pair of strong marginal setae, and with small, hair-like lateral seta; pleura with dense grey pruinosity; propleura with small hairs in front of anterior spiracle, and with 1 strong seta ventrally. Legs: Entirely light yellow (including coxae). Fore leg: coxa with some strong anterior setae; femur without strong setae; tibia with strong ad setae at 1/4 and 1/2, two small pd setae at same level, and 2–3 apical setae; tarsomeres simple; relative podomere ratios: 40, 44, 22/7/6 /5/5. Mid leg: coxa bare; femur with 1 strong ad seta at 4/5; tibia with small ad seta at 1/5, strong ad setae at 1/4 and 2/3, small pd seta at 1/5, strong pd setae at 1/3 and 2/3, with strong av setae at 1/3 and 1/2, and with ring of strong apical setae; tarsomeres simple; relative podomere ratios: 52, 54, 31/ 22/15/10 /7. Hind leg: coxa with 1 strong lateral seta at 1/3; femur with 4–5 strong dorsal setae on basal 1/3, and with strong ad seta at 2/3; tibia with a row of 3 ad/pd setal pairs on basal half, 1 strong ad seta subapically, 1 long and thin, sinuous dorsoapical seta, and with 1 pale and 1 black small apically curved posteroapical projections (MSSC); basitarsus with 1 strong dorsal seta; relative podomere ratios: 53, 55, 20/ 25/13/10 /7. All claws and pulvilli simple. Wing: Hyaline, veins whitish yellow; R3+4 slightly curved posteriad in distal half; M with strong anterior bend at 1/2 beyond dm-cu, converging with R4+5 and joining costa anteriad of wing apex; crossvein dm-cu at 1/2 from base of CuA; CuAx ratio: 0.25; RMx ratio: 4.5; lower calypter white with white setae; halter yellowish white. Abdomen: Mostly dark brown, with grey pruinosity, segments 1 and 2 yellow; segments 3–5 with narrow yellow apical rim; epandrium basally dark brown, apically yellow, cercus and surstylus yellow. Hypopygium ( Figs 1 A–D): epandrium about 2 times longer than wide; basiventral epandrial lobe not developed, basiventral epandrial seta positioned subapically on infolded ventral epandrial margin; apicoventral epandrial lobe very reduced, bearing modified sinuous dorsal seta and 2 closely approximated ventral setae; ventral lobe of surstylus short with 1 seta near base and several closely approximated apical setae; dorsal lobe of surstylus digitiform with thick peg-like dorsal seta and several apical setae; cercus setose, with blunt-tipped thumb-like apicolateral projection; hypandrium elongate, narrow in ventral view; phallus slender, finely wrinkled. Female: Similar to male, but face slightly broader; hind tibia without posteroapical projections; terminalia ( Figs 1 E, 1F) as in generic description.

Etymology. The name refers to the country where the species was found.

Remarks. This species was referred to as “ Argyrochlamys sp. 1” in Brooks (2005).

Phoomyia thailandensis Naglis & Grootaert sp. nov. ( Figs 2 , 3)

Type material. HOLOTYPE 3: THAILAND: Chonburi province, Hat Nang Ram, 13.IX.2002, in crab burrows on sandy beach (reg. 22019, leg. P. Grootaert) (RBINS). PARATYPES: THAILAND: 4 3, 1Ƥ: same data as holotype; 1Ƥ: same data as holotype, but 19.IX.2002, sandy beach (22025, leg. P. Grootaert); 1 3, 1 Ƥ: Chonburi province, Sattahip, 11.IX.2002, sandy beach (reg. 22016, leg. P. Grootaert); 1 Ƥ: Rayong province, Laem Mae Phim, 24.IX.2002, sandy beach (reg. 22039, leg. P. Grootaert) (all RBINS).

Description. Male. Length (holotype): body 2.8 mm, wing 2.7 mm. All setae brown yellow except as noted. Head: Face broad, at narrowest part 2.0 times as wide as distance between ocellar setae, with dense silvery-white pruinosity; clypeus rounded apically, not projecting beyond lower eye margin; palp short, yellow; antennal segments yellow, with yellow setae, arista black; scape with dorsal hairs; about as long as pedicel; pedicel short, with apical ring of short setulae; first flagellomere ovate, rounded apically, as long as high; arista dorsal to dorsoapical, bare, 2.0 times as long as first flagellomere, first segment short, second segment 3 times longer than first segment; frons broad, with dense grey pruinosity; pair of strong vertical setae on level of ocellar setae; pair of strong ocellar setae, as long as vertical setae; pair of strong postvertical setae; postocular setae uniseriate. Thorax: Mesonotum and scutellum covered with dense grey pruinosity; 6 pairs of strong dorsocentral setae, fifth pair offset medially; 5 pairs of acrostichal setae; scutellum with pair of strong marginal setae, and with small, hair-like lateral seta; pleura with dense grey pruinosity; propleura with small hairs and 1 strong seta in front of anterior spiracle, and with 1 strong seta ventrally. Legs: Entirely yellow (including coxae). Fore leg: coxa with some strong anterior setae; femur without strong setae; tibia with strong ad setae at 1/4 and 1/2, two small pd setae at same level, and 2– 3 apical setae; tarsomeres simple; relative podomere ratios: 50, 44, 24/ 12/9/7 /5. Mid leg: coxa bare; femur with 1 strong ad seta at 4/5; tibia with small ad seta at 1/5, strong ad setae at 1/4 and 2/3, small pd seta at 1/5, strong pd setae at 1/3 and 2/3, with strong av seta at 1/2, and with ring of strong apical setae; tarsomeres simple; relative podomere ratios: 60, 65, 43/30/ 20/15/5. Hind leg: coxa with 1 strong lateral seta at 1/2; femur with short dorsal and ventral setae on basal 2/3, and with strong ad seta at 2/3; tibia with a row of 3 ad/pd setal pairs on basal half, 1 strong ad seta subapically, 1 long and strong, sinuous dorsoapical seta, and with 1 pale and 1 black small apically curved posteroapical projections (MSSC) (Fig. 3C); basitarsus (Fig. 3C) with 1 strong dorsal seta; relative podomere ratios: 64, 65, 30/40/ 20/17/7. All claws and pulvilli simple. Wing (Fig. 3B): Hyaline, veins yellow; R3+4 slightly curved posteriad in distal half; M with strong anterior bend at 1/2 beyond dm-cu, converging with R4+5, joining costa anteriad of wing apex; crossvein dm-cu at 1/2 from base of CuA; CuAx ratio: 0.35; RMx ratio: 4.0; lower calypter and setae pale yellow; halter yellow. Abdomen: Mostly dark brown, with grey pruinosity, segments 1–5 with narrow yellow apical rim; epandrium entirely dark brown, cercus and surstylus yellow. Hypopygium ( Fig. 2 ): epandrium about 2 times longer than wide; basiventral epandrial lobe not developed, basiventral epandrial seta positioned subapically; apicoventral epandrial lobe very reduced, bearing 1 curved and 1 straight ventral setae; ventral lobe of surstylus short with 1 subapical and 2 apical setae; dorsal lobe of surstylus digitiform with 1 subapical and 2 small apical setae; cercus with acute fin-like apicolateral projection ( Fig. 2 A); hypandrium elongate, narrow in ventral view; phallus slender, finely wrinkled. Female: Similar to male, but face slightly broader; hind tibia lacking posteroapical projections; terminalia similar to that of P. srilankensis .

Etymology. The name refers to the country where the species was found.

Remarks. Phoomyia thailandensis was not only observed in crab burrows on bare sand in the more humid lower supralittoral zone, but also in crab burrows on the dryer, vegetated supralittoral embryonal dunes covered with Beach Morning Glory or Goat's Foot ( Ipomoea pes-caprae (L.) R.Br.).

FIGURE 3. Phoomyia thailandensis Naglis & Grootaert sp. nov., male (A) habitus; (B) wing; (C) hind leg: apex of tibia and basal portion of tarsus. Abbreviation: t1, tarsomere 1 (basitarsus).

Figures

FIGURE 1. Phoomyia srilankensis Naglis & Brooks sp. nov. (A) male cercus, dorsal view; (B) hypopygium, left lateral view; (C) ventral lobe of surstylus and apicoventral epandrial lobe; (D) dorsal lobe of surstylus; (E) female terminalia, dorsal view; (F) female terminalia, left lateral view. Abbreviations: cerc, cercus; d sur, dorsal lobe of surstylus; epand, epandrium; hypd, hypandrium; ph, phallus; tg, tergite.

FIGURE 2. Phoomyia thailandensis Naglis & Grootaert sp. nov., male (A) cercus, dorsal view; (B) hypopygium, left lateral view.