Simulium (Simulium) timpohonense Takaoka & Sofian-Azirun

Takaoka, Hiroyuki, Sofian-Azirun, Mohd, Ya’Cob, Zubaidah, Chen, Chee Dhang, Lau, Koon Weng, Fernandez, Kevin & Lardizabal, Maria Lourdes, 2015, Revision of the Simulium (Simulium) melanopus species-group (Diptera: Simuliidae) in Sabah, Malaysia, Zootaxa 3985 (1), pp. 1-30 : 23-27

Simulium (Simulium) timpohonense Takaoka & Sofian-Azirun sp. nov.

Male. Body length 3.0 mm. Head. Slightly wider than thorax. Upper eye consisting of large facets in 15 vertical columns and in 16 horizontal rows on each side. Clypeus black, whitish-gray pruinose, shiny and iridescent when illuminated at certain angles, moderately covered with dark-brown long hairs though mediolongitudinal portion bare. Antenna composed of scape, pedicel and nine flagellomeres, dark brown except scape and pedicel dark yellow to light brown and base of first flagellomere yellow; first flagellomere elongate, 1.6 times length of second one. Maxillary palp light brown except first and second segments dark yellow, third segment medium brown, composed of five segments, proportional lengths of third, fourth, and fifth segments 1.00:1.38:2.81; third segment ( Fig. 12 A) of normal size; sensory vesicle ( Fig. 12 A) of medium-size, ellipsoidal, 0.33 times length of third segment, and with small opening. Thorax. Scutum black except anterolateral calli medium brown, with whitishgray pruinose (bluish iridescent when illuminated at certain angles) pattern as shown in Fig. 12 B; scutum densely covered with dark (brassy when illuminated at certain angles) fine short hairs interspersed with dark-brown long upright hairs on prescutellar area. Scutellum brownish-black, with dark-brown upright long hairs. Postnotum brownish-black, and bare. Pleural membrane bare. Katepisternum longer than depth, brownish black, thinly whitish-gray pruinose and shiny when illuminated at certain angles and bare. Legs. Foreleg: coxa whitish yellow; trochanter yellow except most of posterior surface and part of anterior surface light brown; femur medium brown except base of inner surface yellowish; tibia light brown except apical cap medium brown and outer surface widely white and sheeny when illuminated at certain angles; tarsus black, with thick dorsal crest of short hairs; basitarsus greatly dilated, 5.4 times as long as its greatest width. Midleg: coxa brownish black; trochanter brownish black with base yellow; femur brownish black; tibia medium brown with base yellowish white; tibia with wide white sheen on posterior surface when illuminated at certain angles; basitarsus yellowish white except apical one-fourth or one-fifth light brown, second to fourth tarsomeres light brown except bases of second and third tarsomeres yellowish white, and fifth tarsomere medium brown. Hind leg: coxa dark brown; trochanter yellow though anterior surface somewhat darkened; femur brownish black except base yellowish; tibia brownish black except base yellowish white; tarsus ( Fig. 12 B) dark brown except basal three-fifths of basitarsus (though base slightly darkened) and basal half of second tarsomere yellowish white; basitarsus enlarged, wedge-shaped, gradually widened from base to apex, 4.13 times as long as its greatest width, 0.88 and 0.94 times as wide as greatest width of hind tibia and femur, respectively; calcipala nearly as long as width at base, 0.38 times as wide as basitarsus; pedisulcus well developed. Wing. Length 2.6 mm. Other features as in male of S. (S.) crassimanum . Halter . White except base darkened. Abdomen. Basal scale brownish-black, with fringe of light-brown long hairs. Dorsal surface of abdomen dark brown to brownish black, with dark hairs; segments 2 and 4–7 each with pair of silvery iridescent dorsolateral spots connected medially to each other; ventral surface of segments 2–8 grayish brown except sternites 3–8 dark brown. Genitalia. Coxites, styles and ventral plate in ventral view as in Fig. 12 D. Coxite in ventrolateral view ( Fig. 12 E) nearly quadrate, 0.75 times as long as wide. Style in ventrolateral view ( Fig. 12 F) elongate, 1.67 times length of coxite, 2.59 times as long as its greatest width, sinuous, slightly widened from base to basal onethird, then narrowed to toward round apex, and with stout apical spine; style in medial view ( Fig. 12 G) flattened dorsoventrally except basal one-third swollen dorsally. Ventral plate in ventral view ( Fig. 12 D) Y-shaped, with narrow body, having ventrally produced median process that is bare except parts of lateral and anterior surfaces covered with minute setae, and is furnished with several teeth in vertical row on each posterolateral margin; basal arms of moderate length, stout and divergent; ventral plate in lateral view ( Fig. 12 H) with body and its ventrally produced process with rounded ventral apex, with dentate posterior margin, and covered with minute setae anterolaterally; ventral plate in end view ( Fig. 12 I) with body and ventrally produced median process gradually tapered from middle to apex, bare, with several teeth in vertical row on each lateral margin. Median sclerite in lateral view ( Fig. 12 H) moderately sclerotized, folded backward and then curved dorsally, and in posterior view ( Fig. 12 J) plate-like, nearly parallel-sided. Paramere ( Fig. 12 K) wide basally and with several short parameral hooks apically. Aedeagal membrane ( Fig. 12 L) moderately covered with minute setae, with partially sclerotized dorsal plate ( Fig. 12 M). Ventral surface of tenth abdominal segment ( Fig. 12 N, O) without distinct hairs. Cercus ( Fig. 12 N, O) rounded laterally, with 15 or 16 distinct hairs.

Pupa. Body length (excluding gill filaments) 3.2 mm. Head. Integument ochreous except ventral surface of face yellow, densely and neatly covered with round tubercles: frons with two unbranched short trichomes ( Fig. 13 A) on each side; face with one bifid medium-long trichome ( Fig. 13 B) on each side. Thorax. Integument ochreous except wing sheaths yellow, densely (or moderately on dorsal surface) covered with round tubercles except dorsal surface of posterior two-fifths moderately covered with cone-shaped smaller tubercles, and each lateral surface of posterior one-third almost bare; thorax with two unbranched medium-long stout anterodorsal trichomes ( Fig. 13 C), two medium-long anterolateral trichomes (one unbranched and slender, one bifid and stout) ( Fig. 13 D), one unbranched medium-long stout mediolateral trichome ( Fig. 13 E), and three ventrolateral trichomes (one, short and slender, two medium-long and stout; all unbranched except one medium-long trichome on right side bifid) ( Fig. 13 F) on each side. Gill ( Fig. 13 G, H) with six slender thread-like filaments in pairs arising from short common basal stalk; all pairs short stalked; upper filament of dorsal pair longest (1.6 mm), lower filament of ventral pair shortest (0.9 mm), inner filament of middle pair (1.0 mm), and three other filaments subequal to one another (1.2–1.3 mm); upper filament of dorsal pair thickest, 1.17 times as thick as other filaments which are subequal in thickness to one another when compared basally; all filaments medium brown, gradually tapered toward apices; upper filament of dorsal pair and lower filament of ventral pairs at angle of 45 degrees when their basal portions were viewed laterally; cuticular surface with moderate annular ridges and furrows, though annular ridges becoming indistinct apically, covered with minute tubercles. Abdomen. Dorsally, segment 1 light brown, other segments unpigmented except segment 2 with light brown portion anterolaterally on each side; segment 1 moderately covered with minute tubercles laterally and widely on posterior half, and with one unbranched short hair-like seta ( Fig. 13 I) on each side; segment 2 with one unbranched short hair-like seta, one minute seta and four minute stout setae ( Fig. 13 J) on each side; segments 3 and 4 each with four unbranched hooked spines and one unbranched minute seta on each side; segments 5, 6, 7 and 9 without spine-combs; segment 8 with well-developed spine-combs in transverse row and comb-like groups of minute spines on each side; segment 9 without terminal hooks. Ventrally, all segments unpigmented; segment 4 with two unbranched minute setae on each side; segment 5 with pair of bifid hooks submedially and one unbranched minute seta on each side; segment 6 with pair of bifid inner and unbranched hooks on right side and pair of unbranched inner and outer hooks on left side; segment 7 with pair of unbranched inner and bifid outer hooks on right side and pair of bifid inner and outer hooks on left side; segments 6 and 7 each with one unbranched minute seta on each side. Grapnel-like hooklets absent. Cocoon ( Fig. 13 K, L). Shoe-shaped, with low anteroventral collar, thickly woven, ochreous, not extended ventrolaterally; individual threads invisible; 3.4 mm long by 1.3 mm wide.

Type material. HOLOTYPE: Male (together with its associated pupal exuviae and cocoon), reared from a pupa collected from a small stream (width 1.0 m, depth 7–10 cm, water temperature 16.1˚C, shaded, altitude 1,890 m, 06˚01.870’ N/116˚32.834’ E), slow flowing in a natural forest, Just down of Carson Waterfall, Timpohon, Mt. Kinabalu, Sabah, Malaysia, 9-III-2015, by M. Sofian-Azirun, C.D. Chen & K.W. Lau.

Ecological notes. The pupa of this new species was collected from a plastic sheet in the water. The associated species included S. (S.) aeneifacies .

Etymology. The species name timpohonense refers to the area name, Timpohon, where this new species was collected.

Remarks. The male of this new species is similar to that of S. (S.) sp. in having the fore coxa whitish yellow, but is distinguished from the latter species by the hind tibia brownish black with a yellowish white base and hind basitarsus yellowish white on the basal three-fifths and dark brown on the apical two-fifths ( Fig. 12 C). The male scutal pattern of this new species ( Fig. 12 B) is different from those of other related species.

The pupa of this new species is similar to that of S. (S.) nigripilosum in having the frons and thorax covered with tubercles and shoe-shaped cocoon with a low anteroventral collar ( Fig. 13 K, L), but is distinguished from the latter species by the arrangement of the gill filaments ( Fig. 13 G, H).

Figures

FIGURE 12. Male of Simulium (Simulium) timpohonense sp. nov. (A) Third segment of maxillary palp with sensory vesicle (right side; front view). (B) Scutum showing pruinose pattern (dorsal view). (C) Basitarsus and second tarsomere of hind leg (left side; outer view). (D) Coxites, styles and ventral plate (ventral view). (E) Coxite (right side; ventrolateral view). (F) and (G) Styles (right side; F, ventrolateral view; G, medial view). (H) Ventral plate and median sclerite (lateral view). (I) Ventral plate (caudal view). (J) Median sclerite (caudal view). (K) Paramere (left side; caudal view). (L) Aedeagal membrane (right half; caudal view). (M) Dorsal plate (caudal view). (N) and (O) Tenth abdominal segments and cerci (left side; N, lateral view; O, caudal view). Scale bars. 0.1 mm for C; 0.02 mm for A and D – O.

FIGURE 13. Pupa of Simulium (Simulium) timpohonense sp. nov. (A) Frontal trichomes. (B) Facial trichome. (C) – (F) Thoracic trichomes (C, anterodorsal; D, anterolateral; E, mediolateral; F, ventrolateral). (G) and (H) Anterior half of thorax and gill filaments (right side; G, dorsal view; H, outer view). (I) Slender short seta on dorsal surface of abdominal segment 1. (J) Slender short seta, minute fine seta and minute stout seta on dorsal surface of abdominal segment 2. (K) and (L) Cocoons (K, dorsal view; L, lateral view). Scale bars. 1.0 mm for K and L; 0.1 mm for G and H; 0.02 mm for A – F, I and J.