Syneches walkeri Smith
Creators: name: Menezes, Isis Sá
name: Ale-Rocha, Rosaly
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Hybotidae
Syneches
Syneches walkeri

description: Syneches walkeri Smith
(Figs 92–98, 115, 123)
Syneches walkeri Smith, 1962: 214; Smith, 1967: 11 (catalog); Yang et al., 2007: 315 (catalog).
Diagnosis. Large (about 6.3 mm length). Scape and pedicel dark brown; postpedicel yellow with brown base. Thorax brown with pale golden pruinescence forming a dorsocentral stripe and covering the prescutellar disc; prosternum large; scutellum with two rows of long marginal setae. Abdomen dark brown, apical setae of tergites more robust. Legs with enlarged femora; light brown except coxae, trochanters, basal 2/3 of fore femur and median ring on fore and hind tibiae brown, and hind femur brown with light brown subapical ring. Wing light brown, with pterostigma quadrangular and brown, and small brownish stain at apex of R2+3, and light brown infuscation at apex of vein Rs and dm-cu.
Re-description. Holotype ♂. Body: 6.3 mm. Wing: 6.1 mm. Head. Eye with lower facets larger around buccal opening. Ocellar triangle protuberant with sparse golden pruinescence. Face dark brown with dense grey pruinescence. Antenna with short, dense and golden setulae; scape and pedicel dark brown; pedicel with brown and long marginal setae, reaching beyond half-length of postpedicel; postpedicel yellow with brown base, ovate, small, slightly longer than length of scape and pedicel combined, 1 median dorsal seta, same length as postpedicel; stylus about four times length of antenna, bare on distal 1/7. Postcranium with postocular setae light brown, straight and short at upper portion and longer and proclinate at lower portion of head; postgenal setae yellow. Proboscis light brown; palpus yellow, long, about 1/2 length of proboscis, with short, dense and golden setulae, 3 to 4 short and brown ventral setae at basal half and 1 median on external surface and 3 dorsal setae on distal half. Thorax. Prosternum large. Pronotum light brown with brown, elongate marginal setae, and dense pale golden pruinescence. Scutum high, same height as mesopleuron and rounded; brown, with posterior margin of postpronotal lobe and postalar callus light brown, subshiny, covered with reddish brown pruinescence, with pale golden pruinescence forming dorsocentral stripe and covering prescutellar disc; setae brown, slender, moderately long and sparse, longer on prescutellar disc; 8 acrostichal series, 1 dorsocentral series; scutellum brown with pale golden pruinescence. Pleura brown with dense golden pruinescence, except slightly darker meron. Chaetotaxy: 3 dc, posterior seta longer and more robust, about 6 long acr, 2 longer and more robust, all on prescutellar disc; 2 long and robust npl, largely separated from each other; 1 very long and robust pal and another short and weak; scutellum with 2 overlapped rows of long setae, anterior row with robust setae, 1 pair apical and 1 longer subapical and 2 lateral setae about 1/4 length of apical pair; posterior row with 1 robust apical pair and 5 weak pairs about 1/2 length of apical pair. Legs. Elongate with enlarged femora, hind tibia slightly dilated and hind tarsomere 1 enlarged. Light brown except coxae, trochanters, basal 2/3 of fore femur and median ring on fore and hind tibiae brown; hind femur brown with light brown subapical ring. Fore tibia with D row of longer and robust setae. Mid femur with AV row of long and robust setae and PV row of more slender setae. Mid-tibia with 4 long PD setae; one sub-basal and one preapical AD seta; 1 preapical AV seta; PV surface with 1 apical, 1 preapical and 1 seta after middle, first two setae more slender and half-length of apical seta; 1 preapical, slender P seta. Hind femur with 1 preapical PV seta; 4 D setae on apical 1/3; row of long and robust AD setae; AV row of spine-like setae inserted in small tubercles; V row of spine-like short setae becoming more robust towards apex and inserted on large tubercles. Hind tibia with 1 median seta, 1 more slender seta after middle and 1 preapical AD seta; 1 A preapical and 4 AV setae on apical half stronger than covering setae. Hind tarsomere 1 with AV and V rows of robust setae, ventral setae shorter. Wing (Fig. 115). Sub-hyaline, light brown; pterostigma brown, quadrangular, located at end of R1, small brownish stain at apex of R2+3 and light brown infuscation at apex of Rs and dm-cu; apex of R1 slightly curved upwards. Abdomen. About 2.5 times length of thorax. Dark brown with reddish brown pruinescence; setae brown, long and abundant, shorter on dorsum; apical setae of tergites more robust. Tergite 8 short, about twice wider than long, with elongate and strong apical setae, also at membranous portion (Fig. 95); sternite 8 trapezoidal (Fig. 96). Terminalia (Figs 92–94): elongate and robust; hypandrium two times longer than wide, with deep distal median invagination forming two lobes with rounded apex directed medially, with long apical seta reaching beyond apex of phallus; epandrial lamella wide, with strong moderately long setae; phallus short and robust with triangular apex and short sclerotized preapical lateral protuberances; postgonite wide, longer than phallus, with inner margin concave and apex curved backwards. Female. As in male. Terminalia (Figs 97, 98): long and narrow; sternite 8 two times longer than wide, narrowed at basal 1/3, slightly concave distally, with long and strong apical setae; cerci long and slender, almost as long as tergite 10.
Type material examined. HOLOTYPE ♂ (MZUSP): [BRASIL], KM 47, Est[rada]. Rio-S[ão] Paulo, 4.9.1984, J. Miranda L. Conditions of holotype: good, right posterior leg lost and terminalia dissected.
Additional material examined. BRASIL. Amapá, Rio Amapiri, 21.vi.1993, J. Lane col., Comparado com o tipo, Hol[ótipo] Syneches walkeri, Smith, 1962, Det. Ale-Rocha (1 ♂, INPA); Amazonas, Querari (Pelotão), 1°5'N 69°51'W, 6.iv.–16.v.1993, J. Vidal (1 ♀, INPA); Manaus, Res[erva Adolpho] Ducke, Igarapé Barro Branco, Armadilha Malaise 2, 5–16.viii.2004, Henriques A. leg. (1 ♀, INPA); Pará, próximo a Santarém, Fazenda Taperinha, 1– 11.xi.1968, Exp. Perm. Amaz. (2 ♀, INPA); Óbidos, sitio Curió, 01°47′03″ S 55°07′ 05″W, 29.viii.–8.ix.2001, Malaise, J.A. Rafaee & Vidal (1 ♂, INPA); Rondônia, Guajará-Mirim, R[io] Pacaás Novos, 11°11′13″ S 64°51′ 21″W, 7–11.ix.1999, J. Vidal (2 ♀, INPA). SURINAME. Raleigh, Vallen-Voltzberg Res. Foengoe, 4°43′S 56°12′W, 26.i.–15.ii.1982, J. Carpenter & D. Trail (1 ♂, 1 ♀, INPA).
Geographical distribution. Brazil (Amazonas*, Pará*, Rondônia*, Amapá*, Rio de Janeiro), Suriname * (Fig. 123).
Comments. Some specimens are darker in general coloration, with grey pruinescence and stain on the apex of vein R2+3 more tenuous.
Syneches walkeri is similar to S. curvipes, as mentioned above, and can be distinguished from the latter by the wing with brown quadrangular pterostigma located at end of R1, and brown stains on the apices of veins R2+3 and Rs, apex of vein R1 slightly curved upwards, and features of the male terminalia.
According to Smith (1962), S. walkeri is similar to two species: S. simplex Walker, which occurs in North America, and S. catarinae, described from southern Brazil (Santa Catarina). However, S. walkeri differs from S. simplex mainly by the larger size (S. simplex = 3.0 mm; S. walkeri = 6.3 mm) and aspects of its terminalia; and differs from S. catarinae by the light brown hind tibia with brown median ring, wing with quadrangular pterostigma brown, located at the end of R1, and small brownish stain at apex of R2+3, (hind tibia yellow with brown apex, wing with elongate pterostigma at the end of R1 and lacking the stain at the end of R2+ 3 in S. catarinae) and aspects of the terminalia. This species was described from Rio de Janeiro (Brazil) and has also been recorded from northern Brazil.
description: Published as part of Menezes, Isis Sá & Ale-Rocha, Rosaly, 2016, Revision of the Amazonian species of Syneches Walker (Diptera, Hybotidae, Hybotinae), pp. 401-442 in Zootaxa 4103 (5) on pages 433-435, DOI: 10.11646/zootaxa.4103.5.1, http://zenodo.org/record/267788