Syllegomydas Syllegomydas proximus Seguy , 1928, Seguy, 1928

Dikow, Torsten, 2010, New species and new records of Mydidae from the Afrotropical and Oriental regions (Insecta, Diptera, Asiloidea), ZooKeys 64, pp. 33-75: 55-57

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Syllegomydas Syllegomydas proximus Seguy , 1928


Syllegomydas Syllegomydas proximus Seguy, 1928  


The species is distinguished from congeners by the overall dark coloration in the male, the narrow yellow bands on the posterior margin of the abdominal tergites, the dark patterning of the female abdominal tergites, and its apparent distribution on the southern and western edges of the Sahara.

Re-description Male:

Head: brown, in general grey pruinose; width distinctly greater than thorax, interocular distance on vertex larger than at ventral eye margin, vertex between compound eyes slightly depressed, parafacial area less than ½ the width of central facial gibbosity; facial gibbosity distinct, well-developed and discernible in lateral view; mystax white, covering entire facial gibbosity; frons medially apruinose, laterally grey pruinose, vertex medially apruinose, laterally grey pruinose, postgenae apruinose; setation: vertex white, frons white, ocp setae white, pocl setae yellow; ocellar triangle apruinose; proboscis light brown, very short, vestigial, knob-like; labella small, as wide as prementum, only forming distal tip of proboscis, unsclerotised laterally; maxillary palpi cylindrical, light brown, slightly longer than proboscis.

Antenna: brown, scape and pedicel white setose dorsally, brown setose ventrally; postpedicel cylindrical in proximal ½, symmetrically bulbous in distal ½, ≥ 3.0 times as long as combined length of scape and pedicel; apical ‚seta-like‘ sensory element situated apically in cavity on postpedicel.

Thorax: light brown, predominantly grey pruinose; scutum uniformly brown, surface entirely smooth, predominantly grey pruinose, broad sublateral and median stripes (not reaching posterior margin) brown pruinose, scutal setation comprised of distinct rows of long dorsocentral setae and lateral scutal setae; dc setae pre- and postsuturally white, acr setae absent, lateral scutal setae white, npl, spal, and pal setae absent; postpronotal lobe yellow, white pruinose; proepisternum, lateral postpronotum, and postpronotal lobes long white setose; scutellum entirely grey pruinose, asetose, apical scutellar setae absent; mesopostnotum, anatergite, and katatergite grey pruinose, mesopostnotum laterally (close to anatergite) long white setose, anatergite long white setose, katatergite long white setose; katatergite ± flat; anterior anepisternum asetose, supero-posterior anepisternum long white setose; posterior anepimeron long white setose, katepimeron white setose; metepimeron ± flat, yellow, grey pruinose, long white setose; metepisternum grey pruinose, asetose.

Leg: brown, setation brown and white; all coxae grey pruinose, brown setose; met trochanter setose medially; femora brown, met femora ± cylindrical only slightly wider than pro and mes femora, in distal ½ macrosetose, 1 antero-ventral and 1 postero-ventral row of macrosetae; pro and mes tibiae laterally arched, met tibia straight, met tibia cylindrical, ventral keel absent; pro and mes tarsomere 1 longer than tarsomere 2, but less than combined length of tarsomeres 2-3, met tarsomere 1 as long as combined length of tarsomeres 2-4; pulvilli well-developed, as long as well-developed claws, and as wide as base of claws; empodium absent.

Wing: length = 9.0- 9.7 mm; hyaline throughout, veins light brown or light yellow, microtrichia absent; cells r1, r4, r5, m3, + cup closed; C terminates at junction with R1; R4 terminates in R1; R5 terminates in R1; stump vein ( R 3) at base of R4 absent or only very short; R4 and R5 widest apart medially; r-m distinct, R4+5 and M1 apart, connected by crossvein; M1 straight at r-m (not curving anteriorly), M1 (or M 1+ M 2) terminates in R1; CuA1 and CuA2 split proximally to m-cu (cell m3 narrow proximally); M3+CuA1 do not terminate together in C; A1 undulating, cell a1 wide, A1 and wing margin further apart proximally than distally, alula well-developed; halter light brown.

Abdomen: brown; setation comprised of scattered white and brown setae, surface entirely smooth; T1-T7 brown with narrow yellow posterior margins; T1 and anterior ½ of T2 long white setose, remaining T2 and T3 brown setose; T lightly grey pruinose; S1-7 brown, yellow posterior margins; S1 asetose, S2-3 sparsely brown setose; S predominantly apruinose; T2-4 parallel-sided and not constricted waist-like; bullae on T2 light brown, small and circular, surface entirely smooth, T2 surface anterior to bullae smooth.

Male terminalia: T1-7 well-developed, entirely sclerotised, T8 postero-medially weakly sclerotised, with anterior transverse sclerotised bridge connecting lateral scl erites; T7-8 anteriorly with 2 lateral apodemes; S6 regular, without any special setation postero-medially, S8 well-developed and simple, not fused to T8 dorso-laterally, entire (undivided) ventro-medially; epandrium formed by single sclerite (fused medially ± entirely), rounded postero-laterally; subepandrial sclerite without lateral or median protuberances; hypandrium strongly concave, cup-shaped, entirely sclerotised ventrally (forming a single sclerite), entirely fused with gonocoxite, forming a gonocoxite-hypandrial complex; gonocoxites dorso-ventrally flattened in distal ½, higher in proximal ½, without median or lateral protuberance, gonocoxal apodeme absent; 2 functional aedeagal prongs, short and wide, medio-distally free, parallel or diverging laterally, distally straight or only diverging slightly laterally; aedeagal epimere present, distally simple, evenly rounded; lateral ejaculatory processes absent; ejaculatory apodeme formed by single dorso-ventrally oriented plate; ventro-median margin of dorsal aedeagal sheath heavily sclerotised (appearing entirely closed); dorsal aedeagal sheath long, sperm sac entirely covered; sperm sac appearing ± heavily sclerotised.

Re-description Female:

Head: in general densely grey pruinose; vertex between compound eyes ± horizontally straight, medially only slightly below dorsal eye margin; parafacial area more than ½ the width of central facial gibbosity; mystax white, covering entire facial gibbosity, sparse; pocl setae white.

Antenna: scape and pedicel white setose dorsally and ventrally; postpedicel ≥ 4.0 times as long as combined length of scape and pedicel.

Thorax: scutum uniformly light brown; mesopostnotum laterally (close to anatergite) short white setose; anatergite short white setose; katatergite short white setose; posterior anepimeron short white setose; supero-posterior anepisternum short white setose; metepimeron same colour as T1, white pruinose, short white setose.

Leg: light brown, setation predominantly white; all coxae grey pruinose, white setose; femora light brown or yellow; pulvilli reduced, half length of well-developed claws.

Wing: length = 11.2-11.5 mm; r-m distinct, R4+5 and M1 apart, connected by crossvein.

Abdomen: light brown; setation comprised of sparsely scattered short yellow setae, T1 light brown, T2-7 light brown with brown lateral longitudinal and sublateral circular markings; T1-3 sparsely yellow setose; T1-2 anteriorly lightly grey pruinose, T3-7 apruinose; S1 brown, S2-7 light brown with brown lateral longitudinal and median circular markings; S1-3 asetose.

Female genitalia: densely arranged anteriorly directed setae present on T7-8 and S7-8; T9 formed by wide, rectangular sclerite with median protuberance; T9+10 entirely fused, T10 divided into 2 heavily sclerotised acanthophorite plates, 6-8 acanthophorite spurs per plate; 2 spermathecae, all equally large, formed by ± expanded weakly sclerotised ducts and spherical weakly sclerotised reservoirs; individual spermathecal ducts short; S9 (furca) formed by 1 sclerite, ring-like (joined anteriorly and posteriorly), anterior furcal apodeme present, 2 lateral projections forming divided apodeme, lateral furcal apodeme present, median furcal bridge absent.

Material examined:

Niger: Niamey: 1 ♂ Niamey , 13°31'00"N; 002°07'00"E, -. xii.1938, L. Chepard ( AAM-001219, MNHN) GoogleMaps   ; 3 ♂ Niamey , 16.xi.1977, millet field, J. Ritchie ( AAM-000140, AAM-000663-AAM-000664, BMNH)   ; Zinder: 3 ♀ 4 ♂ Dungass (= Dengas) , 13°04'05"N; 009°20'23"E, -. xi.1910, R. Gaillard (1 ♂ holotype, AAM-001220-AAM-001225, MNHN) GoogleMaps   ; Mauritania: Trarza: 1 ♂ Nouakchott , 153 km NE, 18°59'45"N; 015°13'56"W, 20.x.1993, W. Pulawski ( AAM-000116, CAS) GoogleMaps   .


Niger, Mauritania. Biodiversity hotspot/high-biodiversity wilderness area: -/-.


The ♂ specimen (AAM-000116) of this small species from the western edges of the Sahara represents the first Mydidae   species recorded from Mauritania. The species is primarily known from specimens collected in southern Niger (see material examined above that was first mentioned by Séguy 1928, 1941). It has also been recorded from Mali ( Bowden 1980: 333) and North Africa ( Sack 1934: 26). The specimen that Bowden based his assessment on has not been found in the BMNH so that I cannot verify the record from Mali. The northern African distribution is also questionable as this species has not been listed in the Palaearctic catalogue ( Richter and Zaitzev 1988).


France, Paris, Museum National d'Histoire Naturelle


United Kingdom, London, The Natural History Museum [formerly British Museum (Natural History)]


USA, California, San Francisco, California Academy of Sciences