Simulium mainitense, Takaoka & Tenedero, 2019

Takaoka, Hiroyuki & Tenedero, Victor F., 2019, Two new species of the Simulium (Simulium) tuberosum species-group (Diptera: Simuliidae) from Palawan, the Philippines, Zootaxa 4568 (2), pp. 383-393 : 384-389

publication ID	https://doi.org/ 10.11646/zootaxa.4568.2.12
publication LSID	lsid:zoobank.org:pub:5D4B0611-B167-4458-A31C-BD078998F805
DOI	https://doi.org/10.5281/zenodo.5933826
persistent identifier	https://treatment.plazi.org/id/EBEFC4F1-DF1A-498C-94C0-1D64B1F81B69
taxon LSID	lsid:zoobank.org:act:EBEFC4F1-DF1A-498C-94C0-1D64B1F81B69
treatment provided by	Plazi
scientific name	Simulium mainitense
status	sp. nov.

Treatment

Simulium mainitense sp. nov.

urn:lsid:zoobank.org:act:EBEFC4F1-DF1A-498C-94C0-1D64B1F81B69

Female. Body length 2.6 mm. Head. Slightly narrower than thorax. Frons black, shiny with bright reflection when illuminated at certain angles, with several dark stout hairs along lateral margins; frontal ratio 1.4:1.0:1.2; frons:head ratio 1.0:3.6. Fronto-ocular area well developed, short, directed laterally, and rounded apically. Clypeus ( Fig. 1A View FIGURE 1 ) black, slightly shiny, moderately covered with dark-brown medium-long hairs though medial portion of upper threefourths widely bare. Labrum 0.7 times length of clypeus. Antenna composed of scape, pedicel and nine flagellomeres; antenna dark brown, except scape, pedicel and base of first flagellomere yellow. Maxillary palp with five palpomeres, medium brown except palpomere 3 dark brown; proportional lengths of third, fourth, and fifth segments 1.0:1.2:2.8; third palpomere ( Fig. 1B View FIGURE 1 ) somewhat widened, with medium-long ellipsoidal sensory vesicle (0.39–0.45 times length of third palpomere) having medium-sized opening. Maxillary lacinia with 15–17 inner and 17 outer teeth. Mandible with 29 or 30 inner and 10 outer teeth. Cibarium ( Fig. 1C View FIGURE 1 ) with about 40 tiny processes near posterodorsal margin. Thorax. Scutum black, shiny with bright reflection when illuminated at certain angles, moderately covered with brassy short fine hairs interspersed with several dark-brown long upright hairs on prescutellar area. Scutellum dark brown, shiny when illuminated at certain angles, covered with dark-brown upright long and short hairs. Postnotum brownish black, shiny when illuminated at certain angles, and bare. Pleural membrane bare. Katepisternum longer than deep, brownish black, shiny when illuminated at certain angles, and bare. Legs. Foreleg: coxa whitish yellow; trochanter light brown with base whitish yellow; femur light to medium brown with apical cap dark brown; tibia medium brown except apical cap dark brown, with outer surface extensively white except apical cap and with white sheen when illuminated at certain angles; tarsus black, with moderate dorsal hair crest; basitarsus greatly dilated, 4.4 times as long as its greatest width. Midleg: coxa dark brown with posterolateral surface brownish black; trochanter medium brown with base yellow; femur medium brown except apical cap dark brown; tibia medium brown except extreme base yellowish white and apical cap brownish black, and with whitish sheen on posterior surface when illuminated at certain angles; tarsus medium brown except basal four-fifths of basitarsus and basal half of second tarsomere yellowish. Hind leg: coxa medium to dark brown; trochanter yellow; femur dark brown except extreme base yellow; tibia ( Fig. 1D View FIGURE 1 ) medium to dark brown except base yellowish white (when viewed laterally, its border oblique with yellowish white portion extended up to basal one-third of posterior margin) and with whitish sheen on basal half of posterior surface when illuminated at certain angles; tarsus medium brown except basal two-thirds or little more of basitarsus and basal half of second tarsomere yellowish white; basitarsus ( Fig. 1E View FIGURE 1 ) nearly parallel-sided, 5.7 times as long as wide, and 0.7 and 0.6 times as wide as greatest widths of hind tibia and femur, respectively, and with 11 needle-like spines along anterior margin on outer surface; calcipala ( Fig. 1E View FIGURE 1 ) moderately developed, slightly wider than long, and 0.4 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 1E View FIGURE 1 ) well developed; claw ( Fig. 1F View FIGURE 1 ) simple, with tiny swelling subbasally. Wing. Length 1.8 mm. Costa with dark spinules and hairs; subcosta haired except apical half to one-fifth bare; basal section of radius bare; R 1 with dark brown spinules and hairs; R 2 with darkbrown hairs; hair tuft on base of radius dark brown; basal cell absent. Halter . White except basal portion darkened. Abdomen. Basal scale dark brown, with fringe of yellow hairs. Dorsal surface of abdomen medium brown to brownish black, with dark short hairs; tergites 2 and 6–9 shiny when illuminated at certain angles. Ventral surface of segment 7 with pair of round submedian sternites. Terminalia . Sternite 8 ( Fig. 1G View FIGURE 1 ) well sclerotized and bare medially, covered with 9 or 10 long and medium-long stout hairs and two or three short fine hairs on each side. Ovipositor valve ( Fig. 1G View FIGURE 1 ) nearly triangular, rounded posteromedially, membranous except inner margin weakly sclerotized, densely covered with microsetae together with three or four short fine hairs; inner margin slightly concave medially. Genital fork ( Fig. 1H View FIGURE 1 ) of inverted-Y form; stem slender and well sclerotized, with somewhat widened apex; arms of moderate width, each with distinct projection directed forward from lateral ridge. Paraproct in ventral view ( Fig. 1I View FIGURE 1 ) pointed posteromedially, moderately concave anterolaterally, and with strongly sclerotized and darkly pigmented anteromedial surface bearing three sensilla; paraproct in lateral view ( Fig. 1J View FIGURE 1 ) somewhat produced ventrally and slightly posteriorly, 0.55 times as long as wide, covered with 16–19 medium-long stout hairs and numerous microsetae on lateral and ventral surfaces. Cercus in lateral view ( Fig. 1J View FIGURE 1 ) short, rounded posteriorly, 0.35 times as long as its greatest width, and covered with medium-long and short stout hairs. Spermatheca ( Fig. 1K View FIGURE 1 ) ovoidal, 1.2 times as long as wide, well sclerotized except duct and narrow area of juncture with duct weakly sclerotized and unpigmented, without discernible reticulate surface pattern; minute internal setae present; accessory ducts subequal in thickness to each other and slightly thicker than main duct.

Male. Body length 2.5–2.6 mm. Head. Slightly wider than thorax. Upper eye medium brown, consisting of large facets in 14 vertical columns and in 15 or 16 horizontal rows. Clypeus black, thickly white pruinose, silvery shiny when illuminated at certain angles, covered with dark-brown hairs along and near lateral margins (most of central portion bare). Antenna composed of scape, pedicel and nine flagellomeres, brownish black except scape, pedicel and base of first flagellomere dark yellow to light brown; first flagellomere elongate, 1.7 times as long as second one. Maxillary palp grayish to dark brown, composed of five palpomeres with proportional lengths of third, fourth, and fifth palpomeres 1.0:1.3:2.9; third palpomere ( Fig. 2A View FIGURE 2 ) widened apically; sensory vesicle ( Fig. 2A View FIGURE 2 ) small (0.2 times as long as third palpomere), ellipsoidal, and with small opening. Thorax. Scutum black, with white pruinose pattern, i.e., anterior pair of triangular spots (not sharply pointed posteriorly) on shoulders extended posteriorly along lateral margins but not connected to large transverse spot entirely covering prescutellar area; these pruinose areas silvery or bluish iridescent when illuminated at certain angles; scutum uniformly and densely covered with brassy recumbent short hairs interspersed with dark-brown long upright hairs on prescutellar area. Scutellum brownish black, with several dark-brown long upright hairs. Postnotum brownish black, white pruinose when illuminated at certain angles and bare. Pleural membrane bare. Katepisternum longer than deep, brownish black, thinly white pruinose and shiny when illuminated at certain angles, and bare. Legs. Color as in female except hind tibia with small basal portion yellow, and hind basitarsus yellowish white on basal half or little more. Fore basitarsus greatly dilated, 5.6–5.9 times as long as its greatest width. Hind basitarsus ( Fig. 2B View FIGURE 2 ) much enlarged, gradually widened from base to apical two-fifths, then slightly narrowed toward apex, 3.6–3.8 times as long as its greatest width, and 0.8–0.9 and 1.0 times as wide as greatest widths of hind tibia and femur, respectively; calcipala ( Fig. 2B View FIGURE 2 ) small, nearly as long as wide, 0.27 times as wide as greatest width of basitarsus; pedisulcus ( Fig. 2B View FIGURE 2 ) well developed. Halter . White except basal portion darkened. Wing. Length 1.5–1.6 mm. Other characters as in female except subcosta bare. Abdomen. Basal scale brownish black, with fringe of pale (though basally dark) long hairs. Dorsal surface of abdomen brownish black to black, with dark short hairs; segments 2 and 5–7 each with pair of silvery iridescent spots dorsolaterally, those on segment 2 broadly connected in middle to each other. Genitalia. Coxite in ventral view ( Fig. 2C View FIGURE 2 ) subquadrate, slightly longer than wide, covered with several stout hairs near posterior margin. Style in ventral view ( Fig. 2C View FIGURE 2 ) elongate, nearly parallel-sided to middle, then gradually tapered toward apex, with apical spine; style in ventrolateral view ( Fig. 2D View FIGURE 2 ) elongate, nearly parallel-sided from base to basal two-fifths, then gradually tapered toward apex; style in medial view ( Fig. 2E View FIGURE 2 ) 1.6 times as long as coxite, much produced dorsally near base and with several small cone-like spines on dorsal surface. Ventral plate in ventral view ( Fig. 2C View FIGURE 2 ) well sclerotized, with body subquadrate, slightly shorter than wide, and with round projection directed ventrally, which is covered with many minute setae; arms directed forward and somewhat divergent from each other; ventral plate in lateral view ( Fig. 2F View FIGURE 2 ) with posterior margin weakly serrated along basal two-thirds; ventral plate in caudal view ( Fig. 2G View FIGURE 2 ) rounded ventrally, with lateral margin serrated along basal two-thirds, with numerous setae on posterior surface except both areas of dorsolateral corners bare. Median sclerite ( Fig. 2F, H View FIGURE 2 ) plate-like, gradually widened from base toward apex. Paramere ( Fig. 2I View FIGURE 2 ) with three or four distinct hooks. Aedeagal membrane ( Fig. 2J View FIGURE 2 ) moderately covered with minute setae, and with moderately sclerotized dorsal plate in form of horizontal bar ( Fig. 2K View FIGURE 2 ). Abdominal segment 10 ( Fig. 2L, M View FIGURE 2 ) with two to four hairs on lateral surface. Cercus ( Fig. 2L, M View FIGURE 2 ) small, rounded, with six or seven distinct hairs.

Pupa. Body length 3.0 mm. Head. Integument including antennal sheaths yellow; frons moderately covered with round tubercles, and antennal sheath sparsely covered with round and cone-like tubercles and two pairs of unbranched medium-long trichomes ( Fig. 3A View FIGURE 3 ); face with pair of unbranched medium-long trichomes ( Fig. 3B View FIGURE 3 ).

Thorax. Integument yellow, moderately covered with round tubercles except dorsal surface of posterior portion covered with cone-like smaller tubercles; thorax on each side with two medium-long anterodorsal trichomes ( Fig. 3C View FIGURE 3 ), two medium-long anterolateral trichomes (one sometimes shorter than other) ( Fig. 3D View FIGURE 3 ), one medium-long mediolateral trichome ( Fig. 3E View FIGURE 3 ), and three ventrolateral trichomes (one short and two medium-long) ( Fig. 3F View FIGURE 3 ); all trichomes unbranched. Gill ( Fig. 3G View FIGURE 3 ) with six slender thread-like filaments in three pairs (one dorsal, one middle and one ventral) lying somewhat obliquely; no common basal stalk, though basal fenestra distinct; all pairs shortstalked, and stalks of dorsal and ventral pairs lying at angle of 80 degrees when viewed laterally; filaments decreasing in length from dorsal to ventral (though inner filament of middle pair nearly as long as or slightly shorter than outer filament of ventral pair in one pupa), with longest upper filament of dorsal pair (2.0– 2.2 mm long) and shortest lower filament of ventral pair (1.0– 1.3 mm long); relative thickness of filaments from dorsal to ventral when compared basally 1.1:0.9:1.0:0.8:0.9:0.6; all filaments medium brown, tapered toward basal half, then nearly of same thickness up to tip, with distinct annular ridges and furrows, and densely covered with minute tubercles. Abdomen. Dorsally, all segments yellowish; segment 1 with one unbranched medium-long seta ( Fig. 3H View FIGURE 3 ) on each side; segment 2 with one unbranched short seta and five shorter setae ( Fig. 3I View FIGURE 3 ) on each side; segments 3 and 4 each with four distinct hooked spines and one unbranched spinous short seta on each side; segments 5 and 6 lacking spine-combs; segments 7–9 each with distinct spine-combs in transverse row on each side; segments 6–9 each with comb-like groups of micro-spines on each side; segment 9 with pair of small conical terminal hooks ( Fig. 3J View FIGURE 3 ). Ventrally, segments 4–8 each with comb-like groups of micro-spines; segment 4 with one unbranched stout hooklet and few slender minute setae on each side; segment 5 with pair of bifid stout hooks submedially and few unbranched short setae on each side; segments 6 and 7 each with pair of bifid inner and unbranched outer stout hooks somewhat separated from each other, and few unbranched short setae on each side. Grapnel-shaped hooklets absent on each side of segment 9. Cocoon. Wall-pocket-shaped, moderately woven, thin, ochreous, and not extended ventrolaterally; individual threads visible; 2.5–3.1 mm long by 1.0– 1.2 mm wide.

Mature larva. Unknown.

Type material. HOLOTYPE: Male (with its associated pupal exuviae and cocoon) in 80% ethanol, reared from a pupa collected from a river (width 5–6 m, 23.0˚C, shaded, elevation 200 m), moderately flowing in a forest, Mainit, 10 km north of Brooke’s Point, Palawan, Philippines, 21-IX-2009, by H. Takaoka & V. F. Tenedero . PARATYPES: Three females and one male, same data as those of the holotype.

Biological notes. The pupae of this new species were collected from fallen tree leaves in the current. Associated species were S. (G.) epistum Delfinado , S. (S.) quasifrenum , and S. (S.) subatrum Takaoka

Distribution. Philippines (Palawan).

Etymology. The species name mainitense refers to the locality name, Mainit, where this new species was collected.

Remarks. This new species is assigned to the S. tuberosum species-group by having the female scutum not striated, claw simple, ovipositor valve triangular, male ventral plate nearly quadrate when viewed ventrally, style with a basal round protuberance having spines, and pupal gill with six thread-like filaments. This new species is further placed in the S. nitidithorax subgroup, defined by Takaoka (2017), by lacking a pair of clustered stout hairs on the sternite 7 of the female abdomen and a pair of pit-like organs on the pupal thorax.

The female of this new species is distinguished from S. quasifrenum by the relative length of the labrum against the clypeus (0.7 in this new species versus 0.56–0.61 in S. quasifrenum ), the relative length of the sensory vesicle against the third palpomere of the maxillary palp (0.39–0.45 in this new species versus 0.29–0.35 in S. quasifrenum ) and the extent of the white basal portion of the hind tibia (basal one-third on the posterior surface in this new species, as shown in Fig. 1C View FIGURE 1 versus restricted to the basal one-fifth to one-fourth in S. quasifrenum ).

This new species is similar to S. sabahense Smart & Clifford from Sabah and Sarawak ( Smart and Clifford 1969; Takaoka 2008) in many characters including the number of male upper-eye facets, and thoracic integument with round tubercles, but is distinguished from the latter species by the relative length of the anterodorsal trichomes on the pupal thorax against the trichomes on the frons (1.1 in this new species versus 0.7 in S. sabahense ) and length of the gill filaments (longest 2.0– 2.2 mm and shortest 1.0– 1.3 mm in this new species versus longest 1.4–1.7 mm and shortest 0.7–1.0 mm in S. sabahense ).

This new species is similar to S. aeneifacies Edwards from Sabah ( Edwards, 1933; Takaoka, 2008) by having the female sensory vesicle of medium length and pupal gill of similar length and arrangement. It is distinguished from the latter species in the male by the smaller number of upper-eye facets in 14 vertical columns and 15 or 16 horizontal rows (in 16–18 vertical columns and 17–20 horizontal rows in S. aeneifacies ) and in the pupa by the relative length of the anterodorsal trichomes on the pupal thorax against the trichomes on the frons (1.1 in this new species versus 0.7–0.8 in S. aeneifacies ).

This new species is distinguished from the four other species of the S. tuberosum species-group from Sabah and Sarawak by the following characters: from S. alberti Takaoka and S. masilauense Takaoka by the female sensory vesicle of medium-length (much elongated in the other two species), and from S. keningauense and S. lunduense by the dorsal surface of the pupal thorax covered with round tubercles (cone-like tubercles with sharply pointed apices in the latter two species).

Two species of the S. nitidithorax subgroup known from Peninsular Malaysia, S. tani Takaoka & Davies (complex) and S. jasmoni Takaoka, Sofian-Azirun & Belabut , have the elongated female sensory vesicle, differing from that of this new species ( Takaoka and Davies 1995; Takaoka et al. 2012).

Simulium nitidithorax Puri from India is distinguished from this new species in the female by the fore femur yellow on the basal half and blackish on the rest; in the male by the white pruinose anterolateral spots on the scutum connected near the base of the wing to the large posterior spot, and the relative width of the hind basitarsus against the hind tibia (0.7); and in the pupa by the gill with six filaments in three sessile pairs and about 1.7 mm long, and two filaments of the ventral pair subequal in width to each other ( Puri 1932).