Bifidistylus, Reinert, Harbach & Kitching

John F. Reinert, Ralph E. Harbach & Ian J. Kitching, 2009, Phylogeny and classification of tribe Aedini (Diptera: Culicidae), Zoological Journal of the Linnean Society 157, pp. 700-794 : 766-768

BIFIDISTYLUS REINERT, HARBACH & KITCHING ,

GEN. NOV.

Type species: Aedes (Aedimorphus) lamborni Edwards, 1923 .

Females

Head: Vertex with narrow, curved, decumbent scales; occiput and vertex with numerous long, erect, forked scales; ocular line narrow, with narrow, curved scales; eyes above antennal pedicels contiguous or separated by less than diameter of 1 ocular facet; antennal pedicel with several small, broad, white scales and few short, slender setae on mesal surface; clypeus bare; maxillary palpus dark-scaled with apex whitescaled, longer than forefemur.

Thorax: Scutum covered with narrow, curved, dark and pale scales except for bare, median part of prescutellar area, with small group of broad, white scales on prescutellar area mesal to setae on each side; scutellum with broad, silvery scales on all lobes; acrostichal (anterior and posterior), dorsocentral (anterior and posterior) and prescutellar setae well developed; paratergite with broad, white scales; antepronota widely separated, with narrow, curved pale scales, several setae; postpronotum with narrow, curved scales, several posterior setae; postspiracular area with broad, white scales, several setae; subspiracular area with elongate patch of broad, white scales; upper proepisternum with broad, white scales, numerous setae, lower proepisternal area bare; prealar area with few broad, white scales and several setae on upper area, lower area with patch of broad, white scales; mesokatepisternum with moderately large upper and small lower posterior patches of broad, white scales, few upper and several lower posterior setae; mesepimeron with patch of broad, white scales on upper and extending over middle areas, upper setae present, lower setae absent.

Wing: Dark-scaled with small pale-scaled patch at base of costa dorsally, pale-scaled area larger on ventral surface; upper calypter with numerous setae on margin; alula with narrow, dark scales on posterior margin; dorsal tertiary fringe scales dark; remigium with 1 or 2 setae distally on dorsal surface.

Legs: Ante- and postprocoxal membranes bare; hindfemur with white scales at apex; hindtibia darkscaled with white-scaled apical band; hindtarsus dark-scaled, hindtarsomeres 1–4 with white-scaled, apical bands, hindtarsomeres 2–4 with white-scaled, basal bands, hindtarsomere 5 white-scaled; fore-, mid- and hindungues equal, each with 1 tooth.

Abdomen: Tergum I with patch of broad, white scales on laterotergite; terga II–VI with dorsobasal, palescaled areas.

Genitalia: Tergum VIII moderately pigmented, width greater than length, numerous broad scales covering distal area and few scattered scales on proximal area, short setae on approximately distal 0.40, apex flat with several moderately long to long, stout and few short, slender setae; sternum VIII moderately pigmented with heavily pigmented band on distal margin, width greater than length, apex with moderate, median emargination separating somewhat flattened, broadly rounded lobes, numerous broad scales on approximately distal 0.80, seta 2-S inserted posterior to seta 1-S; tergum IX comprised of 2 moderately pigmented, lateral sclerites separated by membrane mesally, each sclerite with apex broadly rounded and bearing 5–13 short, slender setae; postgenital lobe moderately long, moderately wide, apex with moderate, median emargination, several setae on distal area; upper vaginal sclerite moderately pigmented, moderately large; without lower vaginal sclerite; insula tongue-like, without setae; cercus moderately long, moderately wide, apex broadly rounded with few short and few moderately long setae, numerous short setae on much of dorsal surface, numerous broad scales ( Bf. lamborni ) or scales absent ( Bf. boneti kumbae (Chwatt)) ; 3 spermathecal capsules, spherical, 1 large and 2 slightly smaller.

Males

Head: Antennae with distal 2 flagellomeres disproportionally long, remainder of flagellomeres short with numerous long setae directed primarily dorsally and ventrally; maxillary palpus with 5 palpomeres, slightly shorter than proboscis, palpomeres 4 and 5 downturned, palpomeres 4 and 5 and distal part of 3 with numerous long setae lateroventrally.

Legs: Fore- and midungues unequal, each with 1 tooth; hindungues equal, simple.

Abdomen: Terga with numerous long, slightly curved setae laterally.

Genitalia: Tergum IX moderately pigmented, posterior margin with moderate-sized, rounded lobe on each side of relatively narrow, median area, each lobe bearing several slender setae; gonocoxite moderately long, moderately wide, dorsal surface with numerous moderately long, slender setae on mesal area, lateral surface with moderate number of long, stout setae, ventral surface with several short, slender setae on mesal area and several long, stout setae on approximately distal 0.25, numerous broad scales on lateral and ventral surfaces, mesal surface membranous; gonostylus attached at apex of gonocoxite, approximately 0.50 length of gonocoxite, proximal part moderately broad, bifurcated slightly proximal to midlength, outer lobe longer with short subapical seta and somewhat broader than inner lobe which bears 1 short, flattened, bluntly pointed, gonostylar claw at apex; aedeagus comprised of 2 darkly pigmented, lateral sclerites, each with few elongate teeth on approximately distal 0.50, dorsal flap covering sclerites and with proximal part broadly rounded; phallosome with short, narrow, basal piece; proctiger relatively long, with distal part darkly pigmented and pointed, without cercal setae or basal lobe; claspette comprised of small, somewhat rounded, basal plaque bearing few short, slender setae proximally and several short, stout setae distally; sternum IX with 1–4 short setae on median, posterior area.

Pupae

Trumpet: Moderately long; moderately wide distally; tracheoid area weakly developed at base.

Cephalothorax: Setae 1,3-CT similarly developed; 4,5-CT branched, similar in length; 10,12-CT branched; 11-CT normally single, longer than 10,12- CT.

Abdomen: Seta 3-I long, stout, single, longer than 6,7-I; 1-II with numerous slender branches; 2-II inserted lateral to 1,3-II; 3-II,III long, stout, single; 3-III longer than 5-III; 5-V longer than median, dorsal length of tergum VI; 6-VII inserted posterior and slightly mesal to 9-VII, 9-VII branched, longer than 6-VII; 9-VIII with 3–5 branches.

Paddle: Apical margin rounded; midrib extends to near apex of paddle; without hair-like spicules on margins; seta 1-Pa short, single or 2-branched.

Fourth-instar larvae

Head: Seta 1-C slender, single; 4-C short, with 4 or 5 slender branches, inserted mesal and slightly anterior or slightly posterior to 6-C; 5,6-C moderately long, stout, aciculate; 5-C with 8 or 9 branches, inserted posteromesal to 6,7-C; 6-C with 4 branches, close to 5-C, inserted mesal and slightly posterior to 7-C; 7-C moderately long, with 10 or 11 aciculate branches; 12-C short, branched, inserted mesal to 13-C; 13-C with 2–5 branches, longer than 12-C; 14-C single; 19-C absent; antenna moderately long, with spicules, seta 1-A with 4–7 branches.

Thorax: Setae 1–3-P not inserted on common setal support plate, 1-P> 2-P> 3-P length; 5,6-P long, single, 5-P longer than 6,7-P; 7-P long, with 2 or 3 branches; 4-M short, with 2 or 3 branches; 5,7-M long, single, 5-M longer than 7-M; 2-T with 4 or 5 slender branches; 6-T single.

Abdomen: Seta 6-I–VI long, stout, with 2 branches; 7-I long, stout, with 2 or 3 branches; 12-I absent; 8-II branched; 1-VII very long, stout, single, noticeably longer than dorsal length of saddle; 2,4-VIII single; comb comprised of numerous scales in triangular patch; segment X with saddle incomplete ventrally, acus absent, seta 1-X short, single or 2-branched, inserted on saddle, 2-X moderately long, with 7–10 branches, 3-X long, single, ventral brush with several, long, multiple-branched setae, inserted on grid with both transverse and lateral bars, 1 (rarely 2) shorter, branched, precratal seta.

Siphon: Moderately long; acus absent; numerous pecten spines (evenly spaced on proximal 0.50 of siphon and proximal to seta 1-S in Bf. lamborni ; distal spines wider spaced and extending to near apex of siphon, seta 1-S inserted within pecten in Bf. boneti kumbae ).

Included species

Bifidistylus boneti boneti (Gil Collado) , Bf. boneti kumbae and Bf. lamborni .

Distribution

Equatorial Guinea, Kenya, Malawi, Republic of Cameroon, Democratic Republic of Congo, Republic of South Africa and Zambia.

Bionomics

Larvae of Bf. lamborni were collected from a pool of foul water in a cavity in the top of a well-shaded rock on a river bank ( Edwards, 1923a) and in a muddy pool used as a pig-wallow and rock-pools ( Hopkins, 1936, 1952). Immature stages of Bf. boneti kumbae were taken from a rock-pool in a densely shaded stream ( Chwatt, 1948; Hopkins, 1952). Females of Bf. lamborni were taken biting during the day in a forest (scarce), during the night (rare) and in the forest canopy (very rare) ( Haddow et al., 1952).

Discussion

The above generic description is based primarily on specimens examined of Bf. lamborni (♀, ♀g, ♂, ♂g, P and L) and Bf. boneti kumbae (♂, ♂g, P and L) and published information on Bf. boneti boneti ( Gil Collado, 1936; Edwards, 1941). Pao & Knight (1970) described and illustrated the larval maxilla and mandible of Bf. lamborni . Additional descriptive information is provided in Appendix 1 for species included in the analysis.

Etymology

Bifidistylus is derived from the Latin adjective bifidus, - a, - um, meaning split into two parts, bifurcated, and stilus (masculine), meaning a Roman writing instrument. The name is masculine and refers to the bifurcated gonostylus of the male genitalia. Recommended abbreviation of Bifidistylus = Bf.