Crossopalpus albivertex 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 albivertex

description: Crossopalpus albivertex sp. nov.
(Figs 1–5, 23, 24, 31, 36)
Diagnosis. Black species with yellow legs, except all tarsomeres 5 and hind tarsomere 1 brown; antenna black. Dense silvery tomentum on frons and on a distinct round patch on vertex, absent on ocellar triangle. Bristles on scutum almost entirely presutural, except postsutural dorsocentrals. Acrostichal bristles uniserial; dorsocentrals biserial, scarce. Hind femur and hind tibia thickened, hind femur with 3 anteroventral subapical setae in a row, hind tibia with ventral bristles longer.
Description. Holotype male. Body length: 1.19 mm; wing length: 1.34 mm, wing width: 0.49 mm. Head. Shiny black, bare on ocellar triangle, and wide area on upper 1/4 of postocular area; densely covered with silvery tomentum on frons, distinct round patch on vertex (Fig. 23) and on lower 3/4 of postocular area (Figs 23, 24); less dense white tomentum on gena; bristles yellow, setae coppery. Ocellar setae lost [on one female paratype, very long, divergent, upturned and slightly inclinate, stronger than vertical setae]; postocellar setae divergent, minute [on one female paratype, 1/4 length of ocellar setae]. Inner vertical setae convergent, inclinate [on one female paratype 2/3 length of ocellar setae], outer vertical minute, as long as postoculars. Antenna black (Figs 23, 24). Pedicel circled with almost uniformly short apical bristles, 1 long ventral seta twice longer than pedicel; postpedicel short ovate (Fig. 23), 1.5 x longer than pedicel, 1.5 x longer than wide. Stylus brown, 8.3 x longer than pedicel, short pubescent, bare near base. Gena short, almost 1/7 eye height. Palpus yellow, proboscis dark brown, clypeus black, palpus covered with yellow bristles and bearing 1 long and strong dark brown apical seta. Thorax (Figs 23, 24). Shiny black; dark yellow tomentum on posterior margin of prescutellar depression (Fig. 24), margins of postalar callus and scutellum, lower margins of propleuron, katepisternum and meron, entire anatergite, katatergite, and mediotergite. Bristles yellowish, erect, anterior ones slightly shorter, setae coppery. Proepisternum bearing 1 long upturned seta on lower margin. Acrostichal bristles (Fig. 24) uniserial, extended posteriorly to notopleural horizontal plane; dorsocentrals (Fig. 24) biserial, scarce, medial-most dc series with 2 slightly stronger and erect presuturals. Prominent setae: 1 prescutellar dorsocentral about 1/3 length of apical scutellar seta, 1 notopleural and 1 anterior supra-alar both about 1/2 length of apical scutellar seta, 1 posterior supra-alar slightly shorter than anterior supra-alar, and 1 postalar 2/3 length of apical scutellar. Scutellum with 1 apical pair of long setae, 1 lateral and 1 basal pair equally very short, both 1/5 length of apical setae. Legs (Figs 23, 24). Coxae, trochanters, fore and mid femora, fore and hind tibiae, fore and mid tarsomeres 1–4, and hind tarsomeres 2–4 dark yellow; hind femur dark yellow slightly darkened near apex; mid tibia yellow with basal infuscation; hind tarsomere 1 and all tarsomeres 5 dark brown. Covering bristles on legs yellow, setae dark brown; fore tarsomeres 1–4 and mid tarsomeres 2–4 ventrally covered with dense yellowish setulae. Coxae and trochanters with ordinary chaetotaxy. Fore femur slightly thickened near base, ventral bristles somewhat longer near base of femur, and bearing 1 strong anterior and 1 thinner anteroventral subapical seta. Fore tibia 0.9 x length of fore femur, with covering bristles slightly longer, denser, and paler on distal 1/3 of anterior surface; bearing 4 short and erect dorsal bristles through length, and 1 anteroventral and 1 posteroventral strong subapical seta. Fore tarsomeres: 10/6/5 /4/ 10; fore tarsomere 1 with 1 anteroventral and 1 posteroventral row of short spine-like setae. Mid femur slender, ventrally densely setose, bearing 1 stronger anterior and 1 thinner anteroventral subapical seta. Mid tibia subequally long to mid femur, very slender, dorsal bristles somewhat erect, bearing 1 anteroventral and 1 posteroventral strong subapical seta. Mid tarsomeres: 10/7/5 /5/6; mid tarsi lacking prominent bristles. Hind femur strongly thickened throughout, curved toward apex, with 8 erect dorsobasal bristles, bristles not denser ventrally, 2 long and strong anteroventral subapical setae. Hind tibia thickened, as long as hind femur, bristles longer on apical 1/2 of anterior and ventral surfaces, bearing 4 setae near apex: 1 strongest anteroventral and 1 slender anterodorsal, both subapical, and 2 thin anterior apical setae; posteroventral lappet long, strongly pointed, covered with pale yellow dense tomentum. Hind tarsomeres: 22/ 10/8/4 /7; hind tarsomere 1 thickened with ordinary chaetotaxy. Wing (Figs 23, 24, 31). Wide, anal lobe developed. Hyaline with some brown infuscation between veins R 1 and R 4+5, on cell bm and on anal lobe; covered with microtrichia; veins brown. Vein C with 1 very long black seta near base; bristles on first costal section somewhat longer and more widely spaced than in further sections. Costal sections: 24/ 15/18/6. Vein Rs as long as first sector of R 4+5; M 1 gently bowed near apex; M 4 slightly curved and evanescent apically; CuA+CuP apparent as a fold. Crossvein br-m 1/2 length of Rs; crossvein bm-m oblique, 3 x longer than br-m. Cell br wider on medial part, narrowed apically, 3/4 length of cell bm. Halter pale yellow. Abdomen (Fig. 23). Strongly telescoped. Tergites not striated, tergites and sternites shiny black, except tergite 4 opaque, covered with fine pollinosity. Bristles on tergites short, yellow, denser laterally on posterior margin of all tergites, denser laterally and along basal margin of tergite 4; squamiform setae absent; sternites with ordinary setation. Terminalia aligned with body axis, globose, shiny black (Fig. 1). Left cercus very wide bearing numerous short bristles, with deep apical concavity, lateral projection longer and wider than medial projection; right cercus slender, curved, bearing several long bristles (Figs 1, 3). Epandrial lamellae partially fused dorsally (Fig. 1). Left epandrial lamella short, fused to hypandrium. Left surstylus (Fig. 4) very reduced, divided into two lobes: left dorsal lobe strong, elongate, curved inwards, bearing short bristles on apical 1/2; left ventral lobe round, minute, with numerous long apical setae. Right epandrial lamella very wide, evenly covered with short bristles, about as long as left cercus (Fig. 1). Right surstylus (Figs 1, 2) divided into three lobes: right dorsal lobe longest and widest, elongate triangular with only a few short bristles; right medial lobe of intermediary length, club-like, positioned under right dorsal lobe, with 4 apical bristles, 1 stronger; right ventral lobe shortest, fin-shaped, positioned laterally to right dorsal lobe, bearing several short bristles. Hypandrium very short, ejaculatory and ventral apodemes present (Fig. 1).
Female. Similar to male, except mid and hind femora more markedly darker near apex, hind tibia not so thickened, bearing numerous hair-like ventral bristles; tergites paler, shiny brown with some black markings, each sternite with pair of ventral erect bristles. Terminalia (Fig. 5) shortened, tergite 8 short, anterior margin not concave, only slightly sunken mediodorsally; sternite 8 elongate, dorsal margin not elevated in profile, narrowed towards apex, apical 1/2 not strongly bent upwards. Epiproct fused to cercus, hypoproct very short, triangular in lateral view. Cercus bent downwards, bearing numerous very long setae.
Variation. No outstanding variation was found.
Type material. HOLOTYPE ♂ (CZMA). Brasil (MA[Maranhão]), Carolina/ [[PAR[que]NA[cional] Chapada das Mesas,/ Riacho Surucuriú, 240m / 07°07′05.6″S / 47°18′31.6″W / CZMA [white, typeset]; Armadilha de Malaise / 15–31.vii.2013, J.A. Rafael / F. Limeira-de-Oliveira &/ T.T.A. Silva, cols/ CZMA [white, typeset]; Holótipo ♂ / Crossopalpus / albivertex sp. nov. / Freitas-Silva & Ale-Rocha [red, typeset/handwritten]. Holotype condition: Left antennal stylus, right mid tarsus, and left hind tarsomeres 4–5 lost. Specimen with some lepidopteran scales adhered on compound eye, legs (especially tarsomeres), and abdomen. Glued by the right side on a triangle paper point, not dissected. PARATYPES. BRAZIL. Maranhão: Caxias, Fazenda Frexeira, Varredura, 28.ix.2004, F. Limeira-de-Oliveira (1♀, CZMA); idem, except: Por. Olho d'Água das Moças, 24.vii.2012, J.A. Rafael, col. (alcohol 1♀, CZMA). Piauí: Piracuruca, P [arque] N[acional] de Sete Cidades, Posto I [nstituto]C[hico]M[endes de] Bio [diversidade], 04°05′57″S 41°42′34″W, Armadilha Malaise, 1–5.xii.2012, F. Limeira-de-Oliveira, J.S. Pinto Jr, cols (1♂, CZMA, 1♀, INPA). Ceará: Ubajara, P [ar]q[ue] Nac [ional] Ubajara, 21.vi.2012, varredura, J.A. Rafael & Limeira-de-Oliveira, cols (alcohol 1♂, INPA). Paraíba: Cabaceiras, Faz [enda] Bravo, Caatinga do Lajeiro, 8.ix.–27.xi.1986, Malaise, D.S. Amorim (1♂, 1♀, INPA).
Distribution. Brazil (Ceará, Maranhão, Paraíba, Piauí). Crossopalpus albivertex sp. nov. is currently known from the savannah of Northeastern Brazil, and recorded from the eastern to western limits of this biome (Fig. 36).
Etymology. From the Latin, abus = white, vertex = top, referring to the spot of white tomentum on the vertex, very characteristic of the species.
Remarks. Crossopalpus albivertex sp. nov. is similar to C. xanthogaster sp. nov. due to the bristles on the scutum being relatively scarce and almost entirely presutural (postsutural area with only the medial-most dorsocentral series present), hind femur and tibia ventrally setulose, and hind tibia bearing four strong setae near apex. However, C. albivertex sp. nov. has the abdomen and antennae predominantly black, tomentum on frons and on lower 3/4 of postocular area very dense, a patch of silvery tomentum on vertex, and legs predominantly yellow, while in C. xanthogaster sp. nov. the abdomen is yellow, antennae pale brown, tomentum on head not so marked and not forming a patch behind the ocellar triangle, and legs have several dark markings specially on the femora. Crossopalpus albivertex sp. nov., C. goliathus sp. nov., and C. pennescens have darker antennae, with segments almost concolorous, in comparison with other South American species of the genus. However, on the other two species the white tomentum patch on the vertex is absent, the palpi are darker, the scutum has several series of bristles, and they have the second and third costal series subequally long (Melander 1918).
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 113-115, DOI: 10.11646/zootaxa.4559.1.4, http://zenodo.org/record/2626746