Cheiromyia Dyte

Brooks, Scott E., Cumming, Jeffrey M. & Pollet, Marc A. A., 2010, Revision of the Neotropical genus Cheiromyia Dyte (Diptera: Dolichopodidae), Zootaxa 2333, pp. 41-58 : 42-45

Genus Cheiromyia Dyte

Cheirocerus Parent, 1930: 13 . Type species: Cheirocerus palmaticornis Parent [Neotropical], by monotypy. Preoccupied by Cheirocerus Eigenmann, 1917 [Pisces].

Cheiromyia Dyte, 1980: 223 . Type species: Cheirocerus palmaticornis Parent , automatic. Replacement name for Cheirocerus Parent, 1930 .

Recognition. Males can be easily recognized by their distinctive antenna bearing one to several elongate projections on the outer surface of the postpedicel ( Fig. 1 ), and by the large ventrally projecting apv epandrial lobe of the male hypopygium, with a pair of long fine setae. Females of the genus are problematic to recognize if not collected with males, and cannot readily be distinguished from females of Paraclius Loew.

Redescription. Head: Slightly to distinctly broader than high. Vertex slightly to distinctly excavated; 1 pair of strong, inclinate vertical bristles; 1 pair of strong, divergent ocellar bristles; 1 pair of paravertical bristles, subequal to distinctly stronger than uppermost postoculars; postocular setae uniseriate. Face height much greater than height of clypeus. Clypeus subquadrate to subrectangular, lower margin truncate, ending well above lower eye margin. Antenna: scape somewhat enlarged in males, setose dorsally; pedicel somewhat flattened and distorted in males, with marginal setae; male postpedicel modified and elongate with pointed apex and 1 to several elongate projections on the outer surface ( Fig. 1 ); female postpedicel unmodified, short, subtriangular, lacking projections; stylus 2-articled, arista-like. Thorax: Scutum: acr biserial; 6 dc (anterior bristle usually weak), 1 presutural ial, 1 su, 1 strong outer presutural spal, 1 weaker inner presutural spal, 2 postsutural spal, 1 pal and setula, and 2 npl on each side. Scutellum: 1 strong medial bristle and 1 short lateral bristle on each side. Postpronotum with 1 medioclinate bristle and 1-2 weak setae below. Upper proepisternum in front of anterior spiracle with patch of fine hairs, lower proepisternum with 1 strong medioclinate proepisternal bristle and patch of fine hairs medially; pleural surface in front of posterior spiracle bare; metepisternum with a row of 2–3 fine hairs. Legs: I: CxI: anterior surface with dark setulae, 3 strong setae on lateral margin and several long setulae on apical margin; FI with series of 2–4 apical pv setae increasing in size distally, distalmost seta usually distinctly stronger in C. palmaticornis ; TI with 2 dorsal, 1–2 ad and 2 apical (1 dorsal, 1 posterior) bristles, with comb-like row of ad setae (weaker in males); tarsus I longer than TI, It1–5 usually decreasing in length distally (It2 shorter than It 3 in males of C. brevitarsis and C. laselva ) ( Fig. 4 A). II: CxII: anterior surface with dark setulae and setae, 1 stronger seta near outer margin; FII with 1 strong ad preapical bristle, with series of apical pv setae increasing in size distally, distalmost seta sometimes distinctly stronger; TII with 4 ad, 3–4 pd, 2 ventral and 5 apical bristles; tarsus II slightly longer than TII, IIt1–5 decreasing in length distally. III: CxIII with strong lateral seta near apex; FIII with 1 strong ad preapical bristle; TIII usually with 4 ad (3 in C. palmaticornis ), 3 pd, 1 preapical dorsal, 1 weak ventral and 2 apical bristles; tarsus III subequal to or longer than TIII, IIIt1 shorter than IIIt2 with distinct basiventral seta, IIIt2–5 decreasing in length distally. Wing (Figs. 2D,E): Hyaline or with brownish tint; R2+3 weakly sinuous basally, straight in distal section; R4+5 straight, sometimes with a weak posterior curve in distal section; distal section of M beyond dm-cu with strong anterior bend near middle ending above wing apex; crossvein dm-cu subequal to, or longer than distal section of CuA1; calypter with black setae; halter pale. Abdomen: Subconical; tergites 1–5 setose. Male: tergite 6 bare; sternite 2 unmodifed; sternite 3 unmodified to emarginate and membranous posteromedially; sternite 4 strongly emarginate and membranous posteromedially, sometimes divided; sternite 5 mainly membranous, apparently with paired tubular eversible sacs (observed in some specimens); sternite 6 mainly membranous, weakly sclerotized along anterior margin; segment 7 forming tubular peduncle; sternite 8 ovoid to teardrop-shaped, setose. Hypopygium ( Figs. 3 , 4 B-D, 5,6,7): Epandrium subrectangular in lateral view, bv epandrial lobe present or absent (as indicated by bv seta), apv epandrial lobe well-developed, projecting ventrally with a pair of long fine setae, left and right bv and apv epandrial lobes with varying degrees of asymmetry; surstylus divided into digitiform dorsal and ventral arms; postgonite digitiform (upturned in C. palmaticornis ); cercus large, shape various; hypandrium simple, troughlike; sperm pump folded back on itself, with simple single fold, opposing surfaces tightly appressed; phallus tubular, enlarged preapically with dorsal flap-like process, apex narrow; ejaculatory apodeme rather narrow and elongate. Female: Sternites 2–5 setose, unmodified; segments 6–8 bare, tergites and sternites of segments 6 and 7 undivided; tergite 8 and sternite 8 divided medially, tergite and sternite fused anterolaterally forming a narrow sclerite. Tergite10 divided medially into hemitergites each bearing 5 spines, spines rounded and somewhat flattened apically.

Distribution. Cheiromyia is now known from Central America ( Costa Rica), Ecuador, Colombia, Brazil (Acre, Amapá, Amazonas, Roraima, Pará, Maranhão, Sergipe, Pernambuco), Guyana, Surinam, French Guiana and Bolivia (La Paz) ( Fig. 8 ).

FIGURE 2. Male face and wing: (A) Cheiromyia pennaticornis (Parent) ; (B) C. brevitarsis Brooks sp. nov.; (C) C. palmaticornis (Parent) ; (D) C. brevitarsis Brooks sp. nov.; (E) C. pennaticornis (Parent) . Abbreviations: A1: anal vein of wing; CuA1: 1st anterior branch of cubital vein of wing; dm-cu: discal medial-cubital crossvein of wing; R1: 1st radial vein of wing; R2+3: 2nd + 3rd radial vein of wing; R4+5: 4th + 5th radial vein of wing.

Remarks. Capellari and Amorim (2009, figs. 11,12) recently described and illustrated the female terminalia of Cheiromyia brevitarsis Brooks sp. nov. (described below), and noted the proximal fusion of sternite 8 and tergite 8 (character state 70.1 in Brooks 2005). We have also observed this feature in the previously unknown female of the type species, C. palmaticornis . As stated by Capellari and Amorim (2009), the presence of this character state supports the inclusion of Cheiromyia in a clade with Pelastoneurus Loew , Stenopygium Becker , Platyopsis Parent , and Paraclius Loew (in part), including the P. arcuatus lineage (see Brooks 2005, fig. 2).

Figures

FIGURE 1. Male antenna: (A) Cheiromyia bicornis Brooks sp. nov. left antenna (outer surface); (B) C. palmaticornis (Parent) right antenna (medial surface); (C) C. pennaticornis (Parent) right antenna (medial surface) of holotype; (D) C. pennaticornis (Parent) slide preparation of left antenna (outer surface). Abbreviations: pp apex: postpedicel apex; pp proj: postpedicel projection.

FIGURE 3. Cheiromyia bicornis Brooks sp. nov. male terminalia: (A) hypopygium (left lateral view); (B) hypandrium and phallus (ventral view); (C) sperm pump and phallus (left lateral view). Abbreviations: apv lb: apicoventral epandrial lobe; bv lb: basiventral epandrial lobe; cerc: cercus; ej dt: ejaculatory duct; ej apod: ejaculatory apodeme; hypd: hypandrium; ph: phallus; spm pump: sperm pump.

FIGURE 4. Cheiromyia brevitarsis Brooks sp. nov. male foreleg and terminalia: (A) tibia and tarsus of right foreleg; (B) hypopygium (left lateral view); (C) hypandrium and phallus (ventral view); (D) sperm pump and phallus (left lateral view). Abbreviations: apv lb: apicoventral epandrial lobe; cerc: cercus; dsur: dorsal arm of surstylus; ej apod: ejaculatory apodeme; hypd: hypandrium; ph: phallus; spm pump: sperm pump; t: tarsomere; vsur: ventral arm of surstylus.

FIGURE 8. Known distribution of Cheiromyia species: (A) C. bicornis Brooks sp. nov. and C. brevitarsis Brooks sp. nov.; (B) C. laselva Brooks sp. nov., C. palmaticornis (Parent), and C. pennaticornis (Parent).