Crossopalpus xanthogaster Freitas-Silva & Ale-Rocha 2019, sp. nov.
Creators: name: Freitas-Silva, Rafael A. P.
name: Ale-Rocha, Rosaly
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Hybotidae
Crossopalpus
Crossopalpus xanthogaster

description: Crossopalpus xanthogaster sp. nov.
(Figs 20–22, 29, 30, 35, 36)
Diagnosis. Black species with fore and mid femora mostly brownish-yellow, hind femur mostly dark brown, tibiae yellow, except hind tibia with a faint median brownish yellow ring, hind tarsomere 1 not so darkened as other species. Antenna with scape and pedicel brown, postpedicel yellow. Head almost wholly covered with white pruinescence including on upper part of postocular area, lacking tomentum on ocellar triangle, without white spot of tomentum on vertex. Bristles on scutum scattered, almost entirely restricted to presutural area (except dorsocentral medial-most series complete). Hind femur and tibia thickened, hind tibia with bristles longer and denser ventrally. Wing veins pale yellow. Abdomen predominantly yellow.
Description. Holotype male. Body length: 2.00 mm; wing length: 1.42 mm, wing width: 0.57 mm. Head. Shiny black to dark brown (Fig. 30), somewhat brownish near oral margin; bare on ocellar triangle and oral margin; head densely covered with white pruinescence; frons tomentose, denser and silvery tomentum on lower 2/3 of postocular area; bristles yellow, setae coppery. One pair of parallel ocellar setae stronger than vertical setae; postocellar setae minute, about 1/4 length of ocellars. Inner vertical setae long, 2/3 length of ocellar setae, upturned and slightly convergent, outer vertical seta inconspicuous. Antenna (Figs 29, 30) with scape and pedicel light brown, postpedicel yellow. Pedicel circled with almost uniformly short apical bristles, 1 long ventral seta 3 x longer than pedicel; postpedicel short lanceolate, rounded ventrally, 1.6 x longer than pedicel, almost as long as wide. Stylus brown, 11 x longer than pedicel, short pubescent, bare near base. Gena short, about 1/7 eye height. Proboscis yellow, clypeus black, palpus yellow somewhat darkened marginally, covered with yellow bristles and bearing 1 long and strong dark brown apical seta. Thorax (Figs 29, 30). Shiny black with pale yellow tomentum on posterior margin of scutum (Fig. 30), lower margins of katepisternum and meron, fully covering scutellum, postalar callus, katepimeron, katatergite and mediotergite. Bristles yellowish, reclinate, anterior ones shorter, setae coppery. Proepisternum bearing 1 long upturned seta on lower margin. Acrostichal bristles (Fig. 30) biserial, extended posteriorly to horizontal plane of notopleural setae; dorsocentrals (Fig. 30) triserial, median-most dc series complete, bristles more erect and longer, other dorsocentral series extended posteriorly to same horizontal plane of acrostichals. Prominent setae: 1 posterior dorsocentral, 1 notopleural, 2 supra-alars, and 1 postalar, all about 2/3 length of apical scutellar setae, except posterior supra-alar about 1/3 apical scutellar setae. Scutellum with 1 pair of long apical setae and 1 pair of very short lateral setae, about 1/4 length of apical setae. Legs (Fig. 29). Mid and hind coxae, fore and mid tibiae, fore and mid tarsi and hind tarsomeres 2–5 pale yellow; fore coxa dark brown; fore and mid femora brownish-yellow with base and apex yellow; hind femur dark brown with base and apex yellow; hind tibia yellow with faint median brownish yellow ring; hind tarsomere 1 brownish yellow. Covering bristles on legs yellow, setae brown; tarsi ventrally covered with dense white setulae. Coxae and trochanter with ordinary chaetotaxy. Fore femur slightly thickened near base with 1 anterior and 1 posterior thin, subapical seta. Fore tibia as long as fore femur with covering bristles denser on distal 2/3 of anterior surface, bearing 1 anteroventral and 1 posteroventral strong subapical seta. Fore tarsomeres: 11/5/5 /5/10; fore tarsomere 1 with several anteroventral and posteroventral short spine-like setae. Mid femur slender, dorsal bristles near base somewhat erect, ventrally densely setose, bearing 1 strong anterior subapical seta. Mid tibia little shorter than mid femur, bristles erect, bearing 1 anteroventral and 1 posteroventral strong subapical seta. Mid tarsomeres: 12/7/5 /4/10; mid tarsi lacking prominent bristles. Hind femur slightly thickened, somewhat curved towards apex, with 5 erect dorsobasal bristles, bristles denser ventrally, 2 long and strong anteroventral subapical setae. Hind tibia incrassate, little shorter than hind femur, bristles longer and denser ventrally, bearing 4 setae near apex: 1 stronger anteroventral seta, set on short protuberance, and 1 thinner anterodorsal, both subapical setae inserted at same level, and 1 stronger anterior and 1 thinner anterodorsal apical seta; posteroventral lappet long, strongly pointed, covered with long pale yellow tomentum. Hind tarsomeres: 15/ 10/8/6 /6; hind tarsomere 1 thickened with several short ventral spine-like setae near base and 1 anteroventral and 1 posteroventral apical short spine-like seta. Wing (Figs 29, 30, 35). Wide, anal lobe developed. Hyaline with some iridescent reflections and milky appearance; covered with microtrichia; veins pale-yellow. Vein C with 1 very long brown seta near base; bristles on first and 1/2 length of second costal sections about twice longer than in further sections. Costal sections: 29/ 14/22/7. Vein Rs shorter than first sector of R 4+5, M 1 gently bowed near apex, M 4 curved posteriorly, evanescent apically, CuA+CuP indistinct. Crossvein br-m 1/2 length of vein Rs; crossvein bm-m oblique, 3 x longer than crossvein br-m. Cell br wider on medial part, narrowed apically, 2/3 length of cell bm. Halter with base pale yellow and knob white. Abdomen (Fig. 29). Tergites striated, tergites 1–4 and all sternites yellow to brownish, further tergites yellow. Tergites 1 and 5 narrower. Bristles on tergites very short and yellow, sparse; squamiform setae absent; sternites bearing bristles only laterally. Abdomen not dissected. Terminalia globose, shiny brown to dark brown, slightly reflexed to right, globose, short. Cercus deeply bifid (Fig. 21), left cercus very long and wide (Figs 21, 22), both projections narrow and elongate, medial projection covering right surstylus with several moderately long bristles, lateral projection lying laterally following distal margin of left epandrial lamella and partially covering left surstylus, mostly bare except by some short apical bristles; right cercus (Fig. 22) strong, elongate, about as long as medial projection of left cercus, arched, with several long bristles on apical 1/2. Epandrial lamellae partially fused dorsally (Fig. 22). Left epandrial lamella very narrow (Figs 21, 22), fused to hypandrium. Left surstylus (Fig. 21) reduced, apparently divided into two lobes: left dorsal lobe strong, very long, strongly curved behind lateral projection of cercus; left ventral lobe minute. Right epandrial (Fig. 22) lamella very wide, evenly covered long bristles, slightly longer than medial projection of left cercus. Right surstylus (Fig. 21) divided into three digitiform lobes: right dorsal lobe longest and strongest, almost 2/3 length of medial projection of left cercus, apex curved towards ventral; right medial lobe with intermediary length, very narrow, about 1/2 length right dorsal lobe, sinuous near base, right ventral lobe shortest, 1/2 length of right medial lobe.
Female. Similar to male, except fore and mid femora darker, in one specimen almost as dark as hind femur. Terminalia (Fig. 20) elongate, tergite 8 short, anterior margin not concave, not slightly sunken mediodorsally; sternite 8 elongate, dorsal margin not elevated in profile, narrowed towards apex, apical 1/2 projecting posteriorly, not bent upwards. Epiproct fused to cercus, strong, hypoproct elongate, narrow in lateral view. Cercus projecting posteriorly, downwards, bearing numerous short setae, lacking strong bristles.
Variation. No variation was observed.
Type material. HOLOTYPE ♂ (INPA). Bolivia, La Paz, Zongo / 30.i.2005, Arm [adilha] / Malaise, J. Rodrigues [white, typeset]; Holótipo ♂ / Crossopalpus / xanthogaster sp. nov. / Freitas-Silva & Ale-Rocha [red, typeset/handwritten]. Holotype condition: good, glued on rightside to triangular paper point; left stylus and left mid
femur subapical seta lost; not dissected. PARATYPES. Same data as holotype (2♀, INPA).
Distribution. Bolivia (La Paz) (Fig. 36).
Etymology. From the Greek, xanthos = yellow and gaster = belly, stomach, referring to the predominant yellow abdomen of the species.
Remarks. Crossopalpus xanthogaster sp. nov. is similar to C. albivertex sp. nov. and C. aliceae sp. nov. as discussed in the Remarks below each of these species. However, the absence of a patch of white tomentum on the vertex, color of the antenna, bristles scarce on the scutum, almost entire presutural area (except dorsocentral medial-most series complete), wing milky with veins yellow and the abdomen predominantly yellow distinguishes this species from other South American Crossopalpus. Also, this species can be readily identified from its neighbor from Peru, C. armipes, because C. xanthogaster sp. nov. has a smaller number of scutal series of bristles, and the antennae, femora, veins on the wings, and the abdomen are all much paler. Crossopalpus xanthogaster sp. nov. and C. pennescens are similar about the color, but in C. pennescens the palpi and legs are almost black, the scutum is densely bristled and the second and third costal sections are subequally long.
description: Published as part of Freitas-Silva, Rafael A. P. & Ale-Rocha, Rosaly, 2019, New South American species of Crossopalpus Bigot (Diptera: Hybotidae: Tachydromiinae), including biogeographical insights and a reinterpretation of female abdominal tergite 10 in Drapetidini, pp. 111-135 in Zootaxa 4559 (1) on pages 125-129, DOI: 10.11646/zootaxa.4559.1.4, http://zenodo.org/record/2626746