Simulium (Simulium) perakense Takaoka, 2018

Takaoka, Hiroyuki, Ya’Cob, Zubaidah & Sofian-Azirun, Mohd, 2018, Classification, annotated list and keys for the black flies (Diptera: Simuliidae) of Peninsular Malaysia, Zootaxa 4498 (1), pp. 1-65 : 52-59

56. Simulium (Simulium) perakense Takaoka , Ya’cob &Sofian-Azirun, sp. nov. [The LSID for the new name Simulium perakense is urn:lsid:zoobank.org:act:C9C52FE6-D5D2-4C43-AD42-1453E7DC7A3B]

Female. Body length 2.9 mm. Head. Slightly narrower than thorax. Frons brownish black, shiny, with several dark stout hairs along lateral margins; frontal ratio 1.3:1.0:1.2; frons:head ratio 1.0:4.3. Fronto-ocular area well developed, short, directed laterally, and pointed apically. Clypeus brownish black, shiny, moderately covered with dark brown medium-long hairs (though mediolongitudinal portion of upper half widely bare) interspersed with several dark brown longer curved hairs on each side of lower portion. Labrum 0.71 times length of clypeus. Antenna composed of scape, pedicel and nine flagellomeres, and medium to dark brown except scape, pedicel and base of first flagellomere yellow, though first flagellomere entirely yellow when viewed ventrally. Maxillary palp with five segments, medium brown except first and second segments ochreous, and third segment dark brown; proportional lengths of third, fourth, and fifth segments 1.0:1.2: 2.6; third segment ( Fig. 13A ) of normal size, with medium-sized ellipsoidal sensory vesicle (0.34–0.36 times length of third segment) having moderate-sized opening. Maxillary lacinia with 12 or 13 inner and 13 or 14 outer teeth. Mandible with 25 inner and 11 or 12 outer teeth. Cibarium ( Fig. 13B ) with 16 minute processes near posterodorsal margin. Thorax. Scutum brownish black except anterolateral calli medium brown, shiny, densely covered with brassy fine recumbent short hairs interspersed with dark brown short hairs on anterior portion near anterior margin and lateral portions near lateral margins, and several dark brown long upright hairs on prescutellar area; scutum gray pruinose with five nonpruinose longitudinal vittae (one medial, two submedial, and two lateral), all vittae united with transverse nonpruinose band on prescutellar area, when illuminated in front and viewed dorsally; scutum gray pruinose except four non-pruinose longitudinal vittae, when illuminated posteriorly and viewed dorsally. Scutellum dark brown, covered with dark brown upright long hairs and brassy short hairs. Postnotum dark brown, shiny, gray pruinose when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum dark brown, longer than deep, shiny, gray pruinose when illuminated at certain angles, and bare. Legs. Foreleg: coxa and trochanter whitish yellow; femur light brown, with apical cap medium brown; tibia dark brown except basal tip light to medium brown; tarsus brownish black, with moderate dorsal hair crest; basitarsus greatly dilated, 4.6–4.9 times as long as its greatest width. Midleg: coxa brownish black; trochanter medium brownish black except base yellow; femur dark brown; tibia dark brown except base yellowish white; tarsus medium brown except basal two-thirds of basitarsus and basal tip of second tarsomere yellowish white. Hind leg: coxa dark brown; trochanter whitish yellow; femur medium brown except base whitish yellow and apical cap dark brown; tibia ( Fig. 13C ) dark brown except basal one-fifth of anterior surface and basal one-third or little more of posterior surface yellowish white and apical cap brownish black; tarsus medium to dark brown except basal three-fifths of basitarsus and basal half of second tarsomere whitish yellow; basitarsus ( Fig. 13D ) nearly parallel-sided, 5.1–5.5 times as long as wide, and 0.7 and 0.6–0.7 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 13D ) moderately developed, nearly as long as wide, and 0.33 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 13D ) well developed at basal one-third of second tarsomere. Tarsal claw simple, without tooth. Wing. Length 2.5 mm. Costa with dark spinules and hairs; subcosta haired except near apex bare; basal section of radial vein haired except basal one-fourth bare; R1 with dark brown spinules and hairs; R2 with dark brown hairs; hair tuft on stem vein dark brown; basal cell absent. Halter . White except base darkened. Abdomen. Basal scale dark brown, with fringe of brassy fine hairs. Dorsal surface of abdomen dark brown except tergal plate of segment 2 light to medium brown, and with light to dark brown short hairs; tergite 2 shiny and silvery iridescent when illuminated at certain angles and tergites 6–9 shiny. Ventral surface of seventh segment with pair of weakly sclerotized submedian sternal plates. Terminalia . Sternite 8 ( Fig. 13E ) with posterior margin concave medially in form of reversed-U shape, bare medially, with 27 dark medium-long to long stout hairs and 9–12 yellow short hairs on each lateral surface. Ovipositor valve ( Fig. 13E ) rounded posteromedially, with ventrally produced lobe near inner margin, membranous except narrow area along inner margin slightly sclerotized, covered with 14–16 short yellow hairs and numerous microsetae; inner margins slightly sinuous, somewhat separated from each other. Genital fork ( Fig. 13F ) of inverted-Y form, with narrow well sclerotized stem; arms of moderate width, each with moderately sclerotized lateral portion. Paraproct in ventral view ( Fig. 13G ) rounded, slightly longer than greatest width, strongly pigmented on anterior surface, with 42–45 short to medium-long hairs on lateral and ventral surfaces, and with nine short sensilla on anteromedial surface; paraproct in lateral view ( Fig. 13H ) nearly half as long as wide, and much protruding ventrally beyond ventral margin of cercus. Cercus in lateral view ( Fig. 13H ) short, 0.6 times as long as wide, rounded posteriorly, and with numerous short to medium-long hairs. Spermatheca ( Fig. 13I ) nearly ovoid, 1.2 times as long as greatest width, well sclerotized except portion of junction with duct somewhat widely unsclerotized, without definite reticulate patterns on its surface; internal setae present; accessory ducts subequal in thickness to each other, and slightly thicker than major duct.

Male. Body length 2.7–3.2 mm. Head. Slightly wider than thorax. Upper eye consisting of large facets in16– 18 vertical columns and 17–19 horizontal rows. Clypeus brownish black, thickly white pruinose, sparsely covered with dark brown hairs along and near lateral and ventral margins (most of central portion bare). Antenna similar in number of articles and color to that of female; first flagellomere elongate, 1.7 times length of second one. Maxillary palp similar in number of segments and color to that of female; proportional lengths of third, fourth, and fifth segments 1.0:1.3:2.7; third segment ( Fig. 14A ) of normal size; sensory vesicle ( Fig. 14A ) ellipsoidal, 0.25 times length of third segment, and with small opening. Thorax. Scutum brownish black to black, with whitish-gray pruinose pattern, i.e., anterior pair of large spots on shoulders extending posteriorly along lateral margins and connected to large transverse spot entirely covering prescutellar area; anterior pair of large spots divided into anterior half and posterior half, either of which disappears depending on direction of lights; all these spots brilliantly iridescent when illuminated at certain angles; scutum uniformly and moderately covered with brassy recumbent short hairs interspersed with dark brown short hairs near anterior margin and dark brown long upright hairs on prescutellar area. Scutellum dark brown, with dark brown long upright hairs and dark short hairs. Postnotum dark brown to brownish black, shiny and whitish-gray pruinose when illuminated at certain angles and bare. Pleural membrane bare. Katepisternum longer than deep, dark brown to brownish black, and bare. Legs. Color similar to that of female except fore trochanter dark yellow to light brown except base yellow, mid basitarsus yellowish white on basal three-fourths to two-thirds, and hind basitarsus yellowish-white on basal half or little less and medium brown on rest; fore basitarsus moderately dilated, 5.1–6.4 times as long as its greatest width; hind basitarsus ( Fig. 14B ) enlarged, gradually widened toward apical one-third, then nearly parallel-sided or slightly narrowed, 3.6–4.1 times as long as wide, and 0.86–0.87 and 0.90–0.93 times as wide as greatest width of hind tibia and femur, respectively; calcipala ( Fig. 14B ) developed, small, little shorter than its basal width, and 0.27 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 14B ) well developed. Wing. Length 2.2–2.4 mm. Other characters as in female except basal portion of radial vein and subcosta bare. Abdomen. Basal scale dark brown, with fringe of light-brown long hairs. Dorsal surface of abdomen dark brown to brownish black, moderately covered with dark short to medium-long hairs; segments 2, 5, 6 and 7 each with pair of whitish pruinose spots (brilliantly iridescent when illuminated at certain angles) dorsolaterally, those on segment 2 connected broadly to each other in middle. Genitalia. Coxite in ventral view ( Fig. 14C ) nearly quadrate, 1.1 times as long as wide; coxite in ventrolateral view ( Fig. 14D ) rectangular, 0.8 times as long as wide. Style in ventral view ( Fig. 14C ) elongate, gradually narrowed toward middle, then nearly parallel-sided to apex, inner margin gently concave, with subapical spine; style in ventrolateral view ( Fig. 14D ) 1.6 times length of coxite, 2.7 times as long as greatest width near apex; style in dorsomedial view ( Fig. 14E ) with short basal protuberance with well sclerotized, saw-like ragged anterior margin. Ventral plate in ventral view ( Fig. 14C ) with body broad, bearing prominent median process sharply narrowed to round tip; body covered with minute setae medially; arms short, stout, directed forward; ventral plate in lateral view ( Fig. 14F ) with median process abruptly bent ventrally at nearly right angle; ventral plate in caudal view ( Fig. 14G ) in form of equilateral triangle, and bare. Median sclerite in lateral view ( Fig. 14F ) with its base arising in front of anteroventral margin of ventral plate, directed posteriorly and bent dorsally; median sclerite in caudal view ( Fig. 14H ) weakly sclerotized, wide, nearly parallel- sided. Paramere in caudal view ( Fig. 14I ) wide, moderately sclerotized, with several short to medium-long hooks near apex. Aedeagal membrane in caudal view ( Fig. 14J ) sparsely covered with minute setae; dorsal plate indistinct. Abdominal segment 10 ( Fig. 14K, L ) with one or two distinct hairs on ventral surface near each posterolateral corner. Cercus ( Fig. 14K, L ) small, rounded, with 16–18 distinct hairs.

Pupa. Body length 3.0– 3.4 mm. Head. Integument yellow to dark yellow, moderately covered with relatively large tubercles interspersed with small ones near lateral margins; large tubercles round and lacking secondary projections; frons with two unbranched or bifid, medium-long or long trichomes with straight apices, on each side ( Fig. 15A ); face with bifid or trifid, medium-long trichomes with straight apices ( Fig. 15B ). Thorax. Integument yellow to dark yellow, moderately covered with relatively large tubercles except lateral surfaces and dorsal surface of posterior half of thorax moderately covered with small tubercles; thorax on each side with three bifid or trifid, long trichomes with coiled or straight apices) anterodorsally ( Fig. 15C ), two trifid or quadrifid, long trichomes with coiled or straight apex anterolaterally ( Fig. 15D ), one unbranched or bifid medium-long trichome with straight apex mediolaterally ( Fig. 15E ), and three trichomes with straight apices (two unbranched long, one unbranched or bifid short) ventrolaterally ( Fig. 15F ). Gill ( Fig. 15G ) with 10 thread-like filaments arranged as 2+[(2+1)+(2+1)]+2 or 2+[3+(2+1)]+2 from dorsal to ventral, though middle triplets overlapping to each other when viewed laterally; ventral paired filaments (1.0– 1.2 mm long) slightly longer than other filaments (0.8–1.0 mm long), or ventral paired filaments subequal in length to two individual filaments of middle triplets, and slightly longer than remaining six filaments; when compared basally, ventral filament of ventral pair and one individual filament of middle inner triplet thickest, 1.1 times as thick as counter filament of ventral pair, which are as thick as two dorsal paired filaments; all five other filaments of middle triplets 0.8–1.0 times as thick as two filaments of dorsal pair; all filaments light to medium brown, covered with annular ridges and furrows and densely covered with minute tubercles. Abdomen. Dorsally, nearly transparent except segment 1 yellowish; segment 1 without tubercles, with one short slender seta ( Fig. 15H ) on each side; segment 2 with one short slender seta and five minute spinous setae ( Fig. 15I ), of which one is thinner than others, on each side; segments 3 and 4 each with 4 distinct hooks and one short seta on each side; all setae and hooks unbranched; segments 5, 6, 7 and 9 lacking spine-combs; segment 8 with distinct spine-combs in transverse row; segments 6–9 each with comb-like groups of minute spines on each side; segment 9 with pair of cone-like terminal hooks ( Fig. 15J ). Ventrally, segments 4–8 transparent, each with comb-like groups of minute spines; segment 5 with pair of bifid stout hooklets submedially and few unbranched short setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched outer stout hooklets somewhat separated from each other and few unbranched short setae on each side. Cocoon ( Fig. 15K ). Light to dark brown, shoe-shaped, with several small open spaces anterolaterally on each side (shape and size of open spaces are variable by cocoons), strongly woven; posterior half with floor; individual threads visible; 3.5–4.1 mm long, 1.3–1.4 mm wide and 0.8–1.2 mm high.

Mature larva. Body length 5.6 mm. Body grayish. Abdomen in lateral view gradually widened from segment 1 to segment 7, then narrowed to segment 9. Cephalic apotome dark yellow to light brown except anterior twothirds whitish, and narrow median portion along posterior margin medium brown; head spots indistinct except mediolongitudinal spots faintly positive; lateral surface of head capsule dark yellow except eye-spot region whitish and wide areas above and anterior to and posterior to eye-spot region light brown; spots near posterior margin indistinct; ventral surface of head capsule dark yellow; elongate spots on each side of postgenal cleft faintly positive. Antenna composed of three articles and apical sensillum, slightly longer than stem of labral fan; length ratio of three articles (from base to tip) 1.0:1.1:0.6. Labral fan with 52 primary rays. Mandible ( Fig. 16A ) with madndibular serrations composed of two teeth (one large, one small); main tooth at obtuse angle against mandible on apical side; comb-teeth composed of four or five teeth, gradually decreased in length from first to third; supernumerary serrations absent. Hypostoma ( Fig. 16B ) with nine anterior teeth, of which median tooth and each corner tooth subequal in length to one another, and somewhat longer than three intermediate teeth on each side; lateral margins weakly serrate apically; six hypostomal bristles divergent posteriorly from lateral border on each side. Postgenal cleft ( Fig. 16C ) mitre-shaped, large, rounded, 8.3 times length of postgenal bridge and nearly as long as its greatest width; sheath of subesophageal ganglion pigmented. Cervical sclerites composed of pair of light brown pieces, not fused to occiput. Histoblast of pharate pupal gill with 10 thread-like slender filaments of almost same thickness. Thoracic segment 3 and abdominal segments 1–8 each with pair of cone-like or nipple-like dorsolateral protuberances ( Fig. 16D ). Thoracic cuticle sparsely covered with minute unbranched colorless setae. Abdominal cuticle sparsely covered with minute unbranched colorless setae ( Fig. 16D ), and moderately covered with short unbranched colorless setae on each side of anal sclerite. Rectal scales not discernible. Rectal organ of three lobes, each with 14–16 finger-like secondary lobules. Anal sclerite X-shaped, with short broad anterior arms much shorter than posterior ones. Last abdominal segment not bulged laterally and lacking ventral papillae. Posterior circlet with 132 rows of hooklets with up to 22 hooklets per row.

Type specimens. Holotype . Male (with its associated pupal exuviae and cocoon, preserved in 80% ethanol), collected from a moderately flowing river (width 10–15 m, depth 30–50 cm, water temperature 20.0 ˚C, exposed to the sun, elevation 588 m, 04°22'04.7"N, 101°20'03.4"E), near the bridge of the main road, Nineteen Point , Batan Padang Province, Perak State, Peninsular Malaysia, 29-I-2011, by H. Takaoka. Paratypes . Two females, six males (all with their associated pupal exuviae and cocoons), one mature larva, same data as those of the holotype: one female and one male (both with their associated pupal exuviae and cocoons), collected from a ditch (width 0.2–0.3 m, exposed to the sun, elevation 450 m), near the entrance of Resort, Janda Baik, Pahang State, 25-VII-2011, by H. Takaoka.

Biology. The pupae and larvae of this new species were collected from bamboo leaves trailing in water. Associated species were S. (S.) hirtinervis and S. (S.) tani complex.

Etymology. The species name perakense refers to the state name, Perak, where this new species was collected.

Remarks. Simulium (S.) perakense sp. nov. is assigned to the S. striatum species-group by the unique shapes of the female ovipositor valves ( Fig. 13E ) and the male ventral plate ( Fig. 14C ). This new species is characterized by having the haired basal portion of the female radial vein and the pupal gill with 10 slender filaments of almost the same thickness ( Fig. 15G ). In having these characters, this new species is similar to S. (S.) grisescens Brunetti from India ( Brunetti 1911; Puri 1932b), S. (S.) quinquestriatum (Shiraki) from Taiwan ( Shiraki 1935; Takaoka 1979), S. (S.) pingtungense Huang & Takaoka also from Taiwan ( Huang & Takaoka 2008), S. (S.) tavanense Takaoka & Sofian-Azirun and S. (S.) taythienense Takaoka, Sofian-Azirun & Ya’cob, both from Vietnam ( Takaoka et al., 2014c, 2017a) and S. (S.) wuzhishanense Chen from China ( Chen 2003).

This new species is distinguished from S. (S.) grisescens by the relative width of the male hind basitarsus against the hind tibia, which is 0.86 in this new species but 1.0 in S. (S.) grisescens ; from S. (S.) taythienense by the color of the male hind basitarus, which is yellowish on the basal half ( Fig. 14B ) in this new species but on the basal three-fifths or little less in S. (S.) taythienense , and the position of the two middle triplets of the gill, which overlap to each other when viewed laterally in this new species ( Fig. 15G ) but not in in S. (S.) taythienense ; from S. (S.) quinquestriatum and S. (S.) wuzhishanense by the number of upper-eye enlarged facets, which are in 17–19 horizontal rows in this new species but in 16 horizontal rows in S. (S.) quinquestriatum , and in 14 horizontal rows in S. (S.) wuzhishanense , and the color of short hairs on the male scutum, which is brassy in this new species but yellow in S. (S.) quinquestriatum and S. (S.) wuzhishanense ; from S. (S.) tavanense by the basal portion of the male radial vein, which is bare in the new species but haired in S. (S.) tavanense , and the color of hairs on the male scutum, which is brassy in this new species but yellow in S. (S.) tavanense . This new species is easily distinguished from S. (S.) pingtungense and S. (S.) wuzhishanense by the presence of paired dorsal protuberances on the larval abdomen (such protuberances absent in the latter two species).

Simulium (S.) xuandai Takaoka, Sofian-Azirun & Ya’cob, which was described from a male and its associated pupal exuviae from Vietnam ( Takaoka et al., 2014c), is readily distinguished from S. (S.) perakense sp. nov. in the male by the yellowish short hairs on the scutum, and in the pupa by the relatively large tubercles having secondary projections on the head and thoracic integument.

Figures

FIGURE 13. Female of Simulium (Simulium) perakense sp. nov. (A) Third maxillary palpal segment with sensory vesicle (right side; front view). (B) Cibarium (front view). (C) Tibia of hind leg (left side; outer view). (D) Basitarsus and second tarsomere of hind leg (left side; outer view). (E) Sternite 8 and ovipositor valve (right half; ventral view). (F) Genital fork (ventral view). (G) and (H) Paraprocts and cerci (left side; G, ventral view; H, lateral view). (I) Spermatheca. Scales. 0.05 mm for C and D; 0.02 mm for A, B and E–I.

FIGURE 14. Male of Simulium (Simulium) perakense sp. nov. (A) Third maxillary palpal segment with sensory vesicle (right side; front view). (B) Basitarsus and second tarsomere of hind leg (left side; outer view). (C) Coxites, styles and ventral plate (ventral view). (D) Coxite and style (right side; ventrolateral view). (E) Style (right side; dorsal view). (F) Ventral plate with median sclerite (lateral view). (G) Ventral plate (caudal view). (H) Median sclerite (caudal view). (I) Paramere (right side; caudal view). (J) Aedeagal membrane (caudal view). (K) and (L) Abdominal segment 10 and cerci (right side; K, lateral view; L, caudal view). Scales. 0.1 mm for B; 0.02 mm for A and C–L.

FIGURE 15. Pupa of Simulium (Simulium) perakense sp. nov. (A) Frontal trichome. (B) Facial trichome. (C)–(F) Thoracic trichomes (C, anterodorsal; D, anterolateral; E, mediolateral; F, ventrolateral). (G) Gill filaments (left side; outer view). (H) Hair-like seta on dorsal surface of abdominal segment 1. (I) Hair-like seta and minute spinous seta on dorsal surface of abdominal segment 2. (J) Terminal hooks (caudal view). (K) Cocoon (lateral view). Scales. 1.0 mm for K; 0.1 mm for G; 0.02 mm for A–F and H–J.

FIGURE 16. Larva of Simulium (Simulium) perakense sp. nov. (A) Mandible. (B) Hypostoma. (C) Head capsule (ventral view). (D) Nipple-like protuberance and setae on dorsal surface of abdominal segment 5. Scales. 0.1 mm for C; 0.05 mm for B; 0.02 mm for A and D.