Namtokocoris dalanta Sites

Sites, Robert W. & Vitheepradit, And Akekawat, 2007, Namtokocoris Sites, a new genus of Naucoridae (Hemiptera: Heteroptera) in waterfalls of Indochina, with descriptions of six new species, Zootaxa 1588, pp. 1-29 : 14-15

Namtokocoris dalanta Sites , NEW SPECIES

Figs. 3, 6, 10c, 11c, 12c, 13c, 14c

Descriptions

Macropterous male. See generic description; only additional details provided here. Holotype, length 10.21; maximum width 6.31. Paratypes (n = 8), length 9.13–10.21 (mean = 9.72); maximum width 5.89–6.47 (mean = 6.24). Overall coloration dorsally dark brown with yellowish-brown head, pronotum, and wide band at anterior end of embolium gradually narrowing to obsolescence near membrane of hemelytra; heavy dark punctation forming indistinct pattern on head and pronotum, heaviest near posterior margin of head and pronotum in middle 2/3 and posterior to transverse sulcus ( Fig. 10 c). Ventrally, generally medium brown; yellow on anteclypeus, lateral margins of prothorax, and exposed portion of hemelytra.

Head length 1.54, maximum width 3.57, synthlipsis at posteromesal corner 1.30, with four pairs of setal rosettes bordering inner margin of eyes, fifth pair further mesad and slightly ventrad to anterior margin. Antennal proportions 5:6:13:9. Pronotum broad, 3.1 x as wide as long; yellowish spot on midline posterior to transverse sulcus; with elongate, erect setae especially evident laterally; length at midline 1.80; maximum width at posterolateral corners 5.58; posterolateral corners rounded, produced posteriorly ( Fig. 11 c). Scutellum dark reddish-brown, heavily punctate, triangular with distinctly sinuate posterolateral margins, 2.2x as wide as long, width 3.28, length 1.52, pair of longitudinal protuberances each with line of erect setae. Claval commissure length 1.68. Embolium with anterolateral corners abruptly curved ( Fig. 11 c), yellowish anterior band gradually narrowing posteriorly and becoming obsolete near membrane of hemelytra, length 3.85 (chord measurement), maximum width 0.98. All coxae pale yellow, trochanters and femora golden brown, fore tibia/ tarsus darker brown, middle and hind tibia/tarsus golden brown. Leg measurements as follows: foreleg, femur 2.06, tibia 1.20, tarsus 0.36; middle leg, femur 2.12, tibia 1.42, tarsomeres 1–3 0.12, 0.32, 0.32; hind leg, femur 2.72, tibia 2.58, tarsomeres 1–3 0.32, 0.74, 0.76. Posterior margin of mediosternite III straight, IV concave, V strongly concave, VI-VIII increasingly convex. Posterior margin of laterosternite V straight. Genital operculum with posterolateral margins straight, apex acuminate. Parameres rounded distally, flanking lateral margins of and extending to same level as median process of pygophore, stout hairs on mesal 2/3 of dorsal surface; pygophore slightly asymmetrical, median process digitate with long hairs and rounded apex; aedeagus with mid-dorsal carina, basal half parallel sided and straight, penultimate quarter arcuate on right side, narrowing to a parallel-sided, slender distal quarter, series of striations in basal half on right side of mid-dorsal carina ( Figs. 12 c, 13c).

Macropterous female. Paratypes (n = 7), length 9.21–10.04 (mean = 9.65); maximum width 5.81–6.31 (mean = 6.14). Similar to male in general structure and coloration; pad of hairs on middle tibia reduced; posterior margin of mediosternite VI slightly convex; subgenital plate (VII) evenly rounded; posterior margin of laterosternite VI straight ( Fig. 14 c).

Diagnosis

Males of this species can be easily recognized by the nearly straight tip of the aedeagus, whereas all other known species have some degree of curvature to a sharp point to the right. The median process of the pygophore is elongate, digitate, and rounded distally. The female subgenital plate has the apex rounded and the posterior margin of mediosternite VI is slightly convex. The posterolateral corners of the pronotum are rounded and produced posteriorly, which is similar to those of N. kem and N. khlonglan (see below). Specimens in alcohol have a yellow spot completely interrupting the dark band along the posterior margin of the pronotum, although in dried specimens this characteristic is less pronounced. The pronotum is more lightly punctate, thus appearing more yellow than in most congeners, except N. minor , with which it differs substantially in size. The anterolateral margin of the embolium is strongly and abruptly curved.

Discussion

This species was collected at only Thac Dalanta in the vicinity of Da Lat, Vietnam. We sampled other nearby waterfalls (Tiger Waterfall and Thac Premm), but Namtokocoris was not found at these locations. Elephant Falls was not safely approachable. At Thac Dalanta , this insect was in the film of sheeting water on near-vertical rock faces and rock undercuts with a layer of algae ( Fig. 6 ).

Etymology

This species is named for the waterfall, Thac Dalanta , in which it was collected at the type locality.

Repositories

The holotype, allotype, and some paratypes are deposited in the Enns Entomology Museum, University of Missouri-Columbia, U.S.A. Additional paratypes will be deposited in the California Academy of Sciences, San Francisco, U.S. A; the Natural History Museum – Vienna, Austria; and eventually to a museum in Vietnam to be identified.

Material examined

Holotype, macropterous male, and allotype, macropterous female: VIETNAM: Lam Dong Province, Thac Dalanta nr Dalat, N 11o 54.067, E 108o 26.906, elev. 1458 m, 7 July 2007, R. W. Sites & Quang Xuan, rock face of waterfall, L-1011. Paratypes: same data as primary type (7 males, 6 females, 8 nymphs).

Figures

FIGURE 6. Thac Dalanta in Lam Dong Province, Vietnam, the type locality of Namtokocoris dalanta n. sp.

FIGURE 10. Holotypes of a) Namtokocoris siamensis, b) Namtokocoris akekawati, c) Namtokocoris dalanta, d) Namtokocoris kem, e) Namtokocoris khlonglan, and f) Namtokocoris minor.

FIGURE 11. Left margin of pronotum and embolium of macropterous a) Namtokocoris siamensis, b) Namtokocoris akekawati, c) Namtokocoris dalanta, d) Namtokocoris kem, e) Namtokocoris khlonglan, and f) Namtokocoris minor.

FIGURE 12. Genital capsule of males of a) Namtokocoris siamensis, b) Namtokocoris akekawati, c) Namtokocoris dalanta, d) Namtokocoris kem, e) Namtokocoris khlonglan, and f) Namtokocoris minor. Scale bar = 1.0 mm

FIGURE 14. Ventral aspects of terminal abdominal segments of females of a) Namtokocoris siamensis, b) Namtokocoris akekawati, c) Namtokocoris dalanta, d) Namtokocoris kem, e) Namtokocoris khlonglan, and f) Namtokocoris minor.