Namtokocoris siamensis 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 : 8-9

Namtokocoris siamensis Sites , NEW SPECIES

Figs. 1–4 , 10 a, 11a, 12a, 13a, 14a

Descriptions

Macropterous male. See generic description; only additional details provided here. Holotype, length 9.05; maximum width 5.56. Paratypes (n = 20), length 8.30–9.79 (mean = 9.15); maximum width 5.39–5.98 (mean = 5.74). Overall coloration dorsally dark brown with yellowish-brown head, pronotum, and wide band at anterior end of embolium gradually narrowing to obsolescence at or beyond posterior end of embolium; heavy dark punctation forming subtle, indistinct pattern on head and pronotum, heaviest near posteromesal angle of eye and pronotum in middle 2/3 and posterior to transverse sulcus ( Fig. 10 a). Ventrally, generally golden brown; yellowish on anteclypeus, lateral margins of prothorax, and exposed portion of hemelytra.

Head length 1.40, maximum width 3.53, synthlipsis at posteromesal corner 1.20, with four pairs of setal rosettes bordering inner margin of eyes, fifth pair further mesad and slightly ventrad to anterior margin. Antennal proportions 5:6:14:10. Pronotum broad, 2.7 x as wide as long; with elongate, erect setae especially evident laterally; length at midline 2.01; maximum width at posterolateral corners 5.41; posterolateral corners rounded, with pronounced bulge above wing base ( Fig. 11 a). Scutellum dark brown, heavily punctate, triangular with distinctly sinuate posterolateral margins, almost twice as wide as long, width 3.53, length 1.80, line of erect setae on each longitudinal protuberance. Claval commissure length 1.48. Embolium with anterolateral angle strongly curved ( Fig. 11 a), yellowish anterior band gradually narrowing posteriorly and becoming obsolete near posterolateral corner of embolium, length 3.81 (chord measurement), maximum width 0.94. All coxae yellowish brown, trochanters and femora golden brown, fore tibia/tarsus dark brown, middle and hind tibia/tarsus medium brown. Leg measurements as follows: foreleg, femur 1.88, tibia 1.10, tarsus 0.38; middle leg, femur 2.02, tibia 1.44, tarsomeres 1–3 0.14, 0.30, 0.32; hind leg, femur 2.60, tibia 2.58, tarsomeres 1–3 0.28, 0.66, 0.78. Posterior margin of mediosternite III straight, IV concave, V strongly concave, VI and VII convex, VIII broadly pointed. Posterior margin of laterosternite V sinuate. Genital operculum with posterolateral margins straight, apex narrowly rounded. Parameres symmetrical in shape, gently excavate laterally, rounded distally, flanking lateral margins of median process of pygophore, left slightly exceeding right anteriorly; right side of median process of pygophore and right paramere slightly deflected ventrad; median process of pygophore flat-tipped and with fine, elongate setae; aedeagus with mid-dorsal carina, left margin slightly convex, right margin gently curved and widest in basal half, slightly hooked to right at apex, series of striations at middle on left side, another series right of mid-dorsal carina in basal quarter ( Figs. 12 a, 13a).

Macropterous female. Paratypes (n = 20), length 8.55–10.46 (mean = 9.33); maximum width 5.64–6.14 (mean = 5.89). Similar to male in general structure and coloration; pad of hairs on middle tibia reduced; posterior margin of mediosternite V straight; mediosternite VI triangular, narrowly pointed; subgenital plate (VII) with sides convergent, apex terminating in spatulate process; posterolateral corner of laterosternite VI broadly pointed and produced posteriorly ( Fig. 14 a); nearly imperceptible lateral bulge on costal margin of right hemelytron at position of abdominal segment V.

Diagnosis

Males can be recognized by the characteristics of the genitalia. Specifically, the parameres and pygophore are elongate, and the median process of the pygophore is blunt-tipped. Females are readily recognized by the triangular 6th sternite, and spatulate process on the subgenital plate. However, the spatulate tip is pointed in eastern populations. Females also have the posterior margin of laterosternite VI strongly concave. The pronotal margin has a pronounced bulge above the wing hinge, immediately mesad of the rounded posterolateral corner. The scutellar protuberances are distinctly linear. Also, the anterolateral margin of the embolium is strongly and evenly, but not abruptly, curved.

Discussion. With our present knowledge, this is the most widespread of the six species described here. It is found wherever suitable habitat exists, from the mountains near Chiang Mai in the northwest, south to the San Kampang Mountains north of Bangkok, east to the Phanom Dong Rak mountain range on the Cambodian border, and as far northeastward as Phu Pan National Park in Kalasin Province. In the farthest eastern localities of Kalasin, Mukdahan, Sakon Nakhon, and Sisaket provinces, the shape of the female subgenital plate and 6th mediosternite differs from those of specimens in central and northern Thailand. Specifically, the 6th sternite tends to be slightly asymmetrical, and the apex of the subgenital plate is pointed, rather than terminating in a spatulate process. Because of the paucity of nongenitalic characters to distinguish among species, these eastern Thai populations are provisionally assigned to N. siamensis , although further research and collecting is necessary to assess their taxonomic status.

This species occurs in the water film on near-vertical rock surfaces of waterfalls. It is particularly likely to be found in conditions with algal-covered rocks and a film of water moving over the surface. It is predictably found on dripping rock undercuts of the walls of waterfalls. It was collected together with Onychotrechus esakii Andersen ( Hemiptera : Gerridae ) at the type locality ( Fig. 4 ).

This species is probably what was given as an unidentified species of Diaphorocoris by Chen et al. (2005). Although in their illustration, leg spination is not as profuse as in Namtokocoris siamensis , the forelegs appear to bear a single, non-articulated tarsal segment and single claw. Their specimen was collected from a quiet pool of a small stream in Chiang Mai. It is possible that this specimen drifted downstream from a waterfall, as we collected N. siamensis from several small waterfalls in Chiang Mai Province, some with a fall of less than 1 meter.

Etymology

This species is named for the country in which it was first found and throughout which it widely occurs.

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 Royal Forestry Department, Bangkok, Thailand; Entomology Collection, Kasetsart University, Bangkok, Thailand; United States National Museum, Washington, D.C., U.S.A.; California Academy of Sciences, San Francisco, U.S. A; and the Natural History Museum – Vienna, Austria.

Material examined

Holotype, macropterous male, and allotype, macropterous female: THAILAND: Chiang Mai Province, Doi Suthep-Pui National Park, Namtok Mohk Fah, 19°06'N 98°46'E, 600 m, 27 June 2002, rock face of waterfall, Sites, Arnon, Penkae, Taeng-On, L-413. Paratypes: same data as primary type (34 males, 7 females,>100 nymphs); Doi Suthep-Pui National Park, Namtok Monthathan, 18°49'N 98°55'E, 700 m, 8 April 2002, rock face, UMC and CMU teams, L-330 (17 males, 5 females); same locality, 690 m, 15 March 2002, R. W. Sites, L-296 (11 males, 15 females, 3 nymphs); Loei Province, Amphur Phu Rua; Namtok Song Korn, 17°21’N 101°24’E, 728 m, 10 May 2004, Vitheepradit & Prommi, L-676 (10 males, 11 females, 13 nymphs); Nakhon Nayok Province, Khao Yai National Park, Namtok Salika, 14º18’N 101º15’E, 68 m, 7 April 2004, R. W. Sites & A. Vitheepradit, L-606 (76 males, 79 females, 30 nymphs). THAILAND / LAOS: Loei Province, Na Haew National Park, Tahd Heuang International Waterfall, 17°33.990' N 100°59.526'E, 500 m, 10 March 2002, rock face, Sites, Vitheepradit, Kirawanich, L-280 (9 males, 2 females, 8 nymphs).

Additional material examined.

THAILAND: Chiang Mai Province, Doi Suthep-Pui National Park, Namtok Mohk Fah, 19°06'N 98°46'E, 564 m, 13 October 2002, rock face, CMU team; same locality, 18 March 2002, G. W. Courtney; Namtok Monthathan, 18°49'N 98°55'E, 700 m, 5 March 2002, Vitheepradit, Kirawanich, Sites, L-263; same locality, 25 March 2003, Sites, Vitheepradit, Prommi, L-415; same locality, 29 March 2003, UMC and CMU teams, L-427; same locality, 29 April 2003, Vitheepradit, Thamsenanupap, Ferro, L-489; same locality, 19 May 2004, Vitheepradit, Prommi, Laudee, L-697; same locality, 7 June 2002, CMU team; same data, 9 July 2002; same data, 10 August 2002; same data, 25 September 2002; same data, 17 November 2002; same data, 11 December 2002; same data, 12 January 2003; same data, 15 February 2002; same data, 24 April 2003; Namtok Sai Yoi, 18°48'N 98°55'E, 1100 m, 5 April 2002, UMC and CMU teams, L-326; same locality, 5 May 2002, Thamsenanupap; same data, 7 June 2002; same data, 9 August 2002; same data, 17 November 2002; same data, 15 February 2003; same data, 5 April 2003; same data, 12 January 2003; Namtok Huay Pa Lad, 18°48'N 98°54'E, 1250 m, 29 April 2003, Vitheepradit, Thamsenanupap, Ferro, L-488; same locality, 24 March 1994, W. D. Shepard; same locality, 5 March 2002, Vitheepradit, Kirawanich, Sites, L-264; Doi Inthanon National Park, Namtok Mae Klang; 18°29'N 98°40'E, 415 m, 3 April 2002, UMC and CMU teams, L- 320; Namtok Siritharn, 18°32'N 98°34'E, 829 m, 2 May 2003, UMC & CMU teams, L-497; Namtok Pha Dum, 18°36'N 98°31'E, 1379 m, 3 May 2003, UMC and CMU teams, L-499; Kalasin Province, Phu Pan National Park, Namtok Huay Yai, 5 June 1998, stream w/ waterfall & vegetation, Sites, Simpson, Vitheepradit, L-154; same data, 7 June 1998, sheeting water film on rock, L-164; Amphur Khao Wong, Namtok Tad Tong, 16°45’N 104°07’E, 204 m, 25 April 2004, A. Vitheepradit, L-642; Loei Province, Phu Rua National Park, Namtok Huay Pai, 10 June 1998, rock face of waterfall, Sites, Simpson, Vitheepradit, L-175; Namtok Hin Sahm Shan, 10 June 1998; rock face of waterfall, Sites, Simpson, Vitheepradit, L-176; Namtok Phah Paw, Huay Kang Station of Phu Luang Wildlife Sanctuary, 11 June 1998, tiny waterfall trickle, Sites, Simpson, Vitheepradit, L-181; Na Haew National Park; Namtok Wahng Tahd, 17°33.990'N 100°59.526'E, 750 m, 9 March 2002, Vitheepradit, Kirawanich, Sites, L-277; same locality, 17°28'N 100°57'E, 977 m, 25 April 2003, Vitheepradit, Prommi, Setaphan, L-484; Amphur Phu Rua, Namtok Plan Ba, 17°23’N 101°22’E, 649 m, 10 May 2004, Vitheepradit & Prommi, L-675; Mukdahan Province, Phu Pa Yon National Park; Namtok Keang Pho, 16°45’N 104°14’E, 314 m, 23 April 2004, A. Vitheepradit, L-634; Nakhon Ratchasima Province, Khao Yai National Park; Namtok Heaw Su Wat, 14º25’N 101º24’E, 380 m, 6 April 2004, Sites & Vitheepradit, L-605; Tab Lan National Park, Namtok Suan Horm, 14º20’N 101º53’E, 340 m, 13 April 2004, Sites & Vitheepradit, L-623; Namtok Huey Yai, 14º20’N 101º53’E, 338 m, 14 April 2004, Sites & Vitheepradit, L- 624; Namtok Pha Tabak; 6 April 2004, 14º21’N 101º20’E, 395 m, Sites & Vitheepradit, L-604; Phitsanulok Province, Phu Hin Rongkla National Park; Namtok Romglao, 16°59'N 101°00'E, 1190 m, 11 March 2002, Sites, Vitheepradit, Kirawanich, L-288; same locality 6 May 2003, Vitheepradit, Prommi, Ferro, L-507; same locality, 23 Aug 2002, CMU team; same data, 12 Jan 2003; same data, 22 May 2002; same data, 21 June 2002; same data, 15 Dec 2002; Phrae Province, Wieng Ko Sai National Park, Namtok Punjane, 17°56'N 99°34'E, 430 m, 28 March 2003, Sites, Vitheepradit, Prommi, L-424; same locality, 24 Aug 2002, CMU team; same data, 23 May 2002; same data, 24 April 2002; Sakon Nakhon Province, Namtok Huey Yai, 17°01’N 103°59’E, 259 m, 22 April 2004, A. Vitheepradit, L-632; Phu Pa Yon National Park, Namtok Kam Sang, 23 April 2004, 16°55’N 104°09’E, 236 m, A. Vitheepradit, L-635; Sisaket Province, Phanom Dongrak Wildlife Sanctuary, Namtok Samrong Kiat, 14º30’N 104º29’E, 187 m, 12 April 2004, rock face of waterfall, Sites & Vitheepradit, L-621; Uttaradit Province, Phu Soi Dao National Park; Namtok Soi Dao, 17°47'N 100°57'E, 608 m, 24 April 2003, Vitheepradit, Prommi, Setaphan, L-482; Klong Tron National Park; Namtok Klong Tron, 17°36'N 100°44'E, 662 m, 26 April 2003, Vitheepradit, Prommi, Setaphan, L-486; Namtok Mae Cheuy, 17°47'N 100°10'E, 231 m, 27 April 2003, Vitheepradit, Prommi, Setaphan, L-487. THAILAND / LAOS: Loei Province, Na Haew National Park, Tahd Heuang International Waterfall, 17°33'N 100°59'E, 500 m, 10 March 2002, G. W. Courtney; same locality, 25 April 2003, Vitheepradit, Prommi, Setaphan, L-485.

Figures

FIGURE 1. Diagnostic features of Namtokocoris n. gen: a) scutellar protuberances, b) lateral view of midventral prosternal carina, c) male foreleg with one-segmented tarsus and single pretarsal claw, enlarged in (d), of Namtokocoris siamensis n. sp

FIGURE 4. Namtok Mohk Fah in Chiang Mai Province, Thailand, the type locality of Namtokocoris siamensis 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.