Simulium tukurongense, 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 : 389-392

Simulium tukurongense sp. nov.

urn:lsid:zoobank.org:act:BFDCAEB4-0588-42D4-BC61-925A3D6A82A4

Female. Similar to that of S. mainitense sp. nov. except following characters. Body length 2.0– 2.3 mm. Head. Frontal ratio 1.33–1.43:1.00:1.20–1.23; frons:head ratio 1.00:3.55–3.75. Clypeus ( Fig. 4A ) black, slightly shiny, widely bare except narrow portions along lateral and lower margins moderately covered with dark-brown mediumlong hairs. Labrum 0.51–0.59 times length of clypeus. Maxillary palp: proportional lengths of third, fourth, and fifth palpomeres 1.0:1.2:2.7; sensory vesicle 0.38–0.47 times length of third palpomere. Maxillary lacinia with 12– 15 inner and 16–20 outer teeth. Mandible with 25–30 inner and 10 or 11 outer teeth. Cibarium with 45–72 tiny processes near posterodorsal margin. Legs. Fore basitarsus greatly dilated, 4.4–4.6 times as long as its greatest width. Hind tibia medium to dark brown except base yellowish white (when viewed laterally, its border oblique with yellowish white portion extended up to basal one-fourth to one-third of posterior margin). Hind basitarsus ( Fig. 4B ) nearly parallel-sided, 5.6–5.9 times as long as wide, with six to nine needle-like short spines along anterior margin on outer surface. Wing. Length 1.6 mm. Abdomen. Dorsal surface of abdomen medium brown to brownish black except basal half of segment 2 ochreous. Terminalia . Sternite 8 covered with seven or eight long and medium-long stout hairs and two or three short fine hairs on each side. Ovipositor valve densely covered with microsetae together with four to six short fine hairs. Paraproct in lateral view 0.54–0.59 times as long as wide, covered with 13–15 medium-long stout hairs and numerous microsetae on lateral and ventral surfaces. Cercus in lateral view 0.44 times as long as its greatest width. Spermatheca ovoidal, 1.1–1.2 times as long as wide.

Male. Similar to that of S. mainitense sp. nov. except following characters. Body length 2.3 mm. Head. Maxillary palp: proportional lengths of third, fourth, and fifth palpomeres 1.0:1.2:2.5; sensory vesicle small (0.14 times as long as third palpomere), globular, and with small opening. Legs. Fore basitarsus moderately dilated, 5.2– 5.9 times as long as its greatest width. Hind basitarsus yellowish white on little more than basal half, 3.5–3.8 times as long as its greatest width, and 0.9–1.0 times as wide as greatest width of hind tibia and of femur. Genitalia. Style in ventrolateral view nearly parallel-sided from base to basal two-fifths, gradually tapered to apical two-fifths, then nearly parallel-sided or slightly tapered to apex; Abdominal segment 10 with two to five hairs on each lateral surface. Cercus with seven to nine distinct hairs.

Pupa. Similar to pupa of S. mainitense sp. nov. except following characters. Body length 2.5 mm. Head. Frons two pairs of unbranched medium-long trichomes ( Fig. 4C ); face with pair of unbranched medium-long trichomes ( Fig. 4D ). Thorax. Integument on each side with two anterodorsal trichomes (one long, one medium-long) ( Fig. 4E ), two medium-long anterolateral trichomes (one sometimes shorter than other) ( Fig. 4F ), one medium-long mediolateral trichome ( Fig. 4G ), and three ventrolateral trichomes (one short and two medium-long) ( Fig. 4H ); all trichomes unbranched. Gill ( Fig. 4I ) with six slender thread-like filaments in three pairs (one dorsal, one middle and one ventral) lying vertically; all pairs shortly stalked, though stalks of ventral pairs on both sides in one pupa much elongated, right and left stalks 1.2 and 2.3 times length of interspiracular trunk, respectively; upper filament of dorsal pair longest (1.3–1.6 mm), lower filament of ventral pair shortest (0.9–1.1 mm long), and other filaments intermediate in length; relative thickness of filaments from dorsal to ventral when compared basally 1.0:0.8:0.8– 0.9:0.7–0.8:0.7–0.8:0.5. Abdomen. Dorsally, segment 1 with one unbranched medium-long seta ( Fig. 4J ) on each side; segment 2 with one unbranched short seta and five shorter setae ( Fig. 4K ) on each side Cocoon. Wall-pocketshaped, moderately woven with small interspaces on anterior portion; anterior margin tightly woven; 2.5–2.6 mm long by 1.0– 1.1 mm wide.

Mature larva. Unknown.

Type material. HOLOTYPE: Female (with its associated pupal exuviae and cocoon) in 80% ethanol, reared from a pupa collected from the Tukurong River (width 30 m, 23.0˚C, shaded, elevation 160 m), moderately to rapidly flowing in a forest, Montible, Puerto Princesa City, Palawan, Philippines, 28-I-2007, by H. Takaoka & V. F. Tenedero . PARATYPES: Two females and three males (with their associated pupal exuviae and cocoons) in 80% ethanol, reared from pupae, same as the holotype; two females and five males (with their associated pupal exuviae and cocoons) in 80% ethanol, reared from pupae collected from the Estrella River (width 20 m, exposed to the sun, 22.0 ˚C, elevation 110 m), near Estrella Waterfall, Narra, Palawan, Philippines, 29-I-2007, by H. Takaoka & V. F. Tenedero .

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

Distribution. Philippines (Palawan).

Etymology. The species name tukurongense refers to the name of the river, Tukurong, where this new species was collected.

Remarks. As in the preceding species, this new species is placed in the S. nitidithorax subgroup of the S. tuberosum species-group.

This new species is similar to S. mainitense sp. nov. but is barely distinguished from the latter species in the female by the relative length of the labrum against the clypeus (0. 5–0.6 in this new species versus 0.7 in S. mainitense sp. nov.); and in the pupa by the length of the longest gill filament (1.3–1.6 mm in this new species versus 2.0– 2.2 mm in S. mainitense sp. nov.).

This new species is similar to S. aeneifacies from Sabah and S. sabahense from Sabah and Sarawak ( Smart and Clifford 1969; Takaoka 2008) in many characters including the female sensory vesicle of medium-length and pupal thoracic integument with round tubercles, but is distinguished from the latter two species by the relative length of the anterodorsal trichomes ( Fig. 4E ) on the pupal thorax against the trichomes ( Fig. 4C ) on the frons (1.2–1.8 in this new species versus 0.7–0.8 in S. aeneifacies and 0.7 in S. sabahense ).

This new species is distinguished from other six species of the S. nitidithorax from Sabah, Sarawak and Peninsular Malaysia by the following characters: from S. alberti , S. jasmoni , S. masilauense and S. tani (complex) by the female sensory vesicle of medium-length (much elongated in the four 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).

Simulium nitidithorax from India is distinguished from this new species by the female fore femur yellow on the basal half and blackish on the rest, and the pupal gill with six filaments, which are arranged in three sessile pairs, and have two filaments of the ventral pair subequal in width to each other ( Puri 1932).

Figures

FIGURE 4. Female and pupa of Simulium tukurongense sp. nov. (A) Clypeus (front view). (B) Hind basitarsus and second tarsomere (left side; outer view). (C) Frontal trichomes. (D) Facial trichome. (E)–(H) Thoracic trichomes (E, anterodorsal; F, anterolateral; G, mediolateral; H, ventrolateral). (I) Gill filaments (right side; outer view). (J) Hair-like seta on dorsal surface of abdominal segment 1. (K) Hair-like seta and spinous seta on dorsal surface of abdominal segment 2. Scale bars. 0.05 mm for B and I; 0.02 mm for A; 0.01 mm for C–H, J and K.