Hydrometra heoki heoki, heoki, 2004

Zettel, Herbert & Yang, Chang Man, 2004, New Oriental Species And Subspecies Of Hydrometra Latreille (Heteroptera: Hydrometridae), Raffles Bulletin of Zoology 52 (2), pp. 389-398 : 393-396

Hydrometra heoki heoki , new species

( Figs. 11-14 )

Hydrometra gilloglyi Polhemus & Polhemus, 1995: 20-22 (part).

Material examined. – Holotype - (brachypterous male): EAST MALAYSIA: Sarawak, Kg. Temenggong, nr. Kg. Matang, 4 Sep.1995, coll. H. H. Tan ( SKM).

Paratypes – 2 males (brachopterous), 2 females (1 allotype brachypterous, 1 macropterous “morphotype”), same data as holotype (1 male and morphotype in ZRC, 1 male and 1 female in NHMW) ; 3 males, 2 females (brachypterous), Bamboo forest, upstream of Sg. Pelajau , 27 Nov.1997 ( ZRC) ; 1 male, 1 female (macropterous), Kapit, Sg. Semaning, downstream of Rejang , 1 Mar.1998 ( ZRC) ; 4 males, 1 female (brachypterous), Marudi , Sg. Dabaii, 13 Sep.1998 ( SKM, ZRC) ; 3 males, 2 females (brachypterous), Miri, ca. 8km to Batu Niah , 25 Sep.1996, coll. H. H. Tan & Y. Y. Goh ( SKM, ZRC) ; 5 males, 4 females (brachypterous), Sg. Joh, main side stream of Sg. Bloh , 20 Nov.1997 ( SKM, ZRC) ; 3 males, 2 females (brachypterous); 1 female (macropterous), Sg. Stuum Muda, nr. Lundu ferry point at Bg. Kayan , 2 Sep.1996, coll. H. H. Tan & S. H. Tan ( ZRC, NHMW) ; 3 males, 3 females (brachypterous), Baram basin, Bario plateau, Pa’Umor , Dapur river , 10 Jun.2002 ( SKM, ZRC) ; 3 males, 3 females (brachypterous), Rejang basin, Sg. Sebaneng ( Semaning ), 19 Jun.2002, ( ZRC) ; 3 females (brachypterous), Kelabit Highland, 1000 - 1200 m, Bareo, Pa’Ukat , bank of stream, 27 Feb.1993, coll. H. Zettel # 12 ( NHMW) ; Sabah : 5 males, 2 females (brachypterous), Danum, Sg. Bilong , 3 Oct.1996, coll. H. H. Tan & Y. Y. Goh ( ZRC, NHMW) ; 1 male, 1 female (macropterous); 3 males, 5 females (brachypterous), Danum, Sg. Bole Kechil , 2 Oct.1996, coll. H. H. Tan & Y. Y. Goh ( SBM, ZRC) ; 1 male (brachypterous) Danum Valley, Palum Tambun , 7 –12 Feb. 1997, coll. H. Zettel & al. #P88 ( NHMW) ; 1 male, 1 female (brachypterous) same data except #P24 ( NHMW) ; 1 male (brachypterous), Danum Valley, Sapat Kalisan , 12 Feb.1997, coll. H. Zettel #15 ( NHMW) ; INDONESIA: Kalimantan : 6 males, 5 females (brachypterous), Kalimantan Tengah, Barito Basin, Barito Utara, Sg. Baubau and feeder streams at 52 km, 7 Apr.2000 ( MZB, ZRC) ; 5 males, 8 females (brachypterous), Kalimantan Timur, Kayan Basin, Sg. Nga’ha , 24 Nov.1999 ( MZB, ZRC) ; 3 males, 1 female (brachypterous), Kalimantan Timur, Mahakam Basin, Long Iram subdistrict, Sg. Pari at mouth of Sg. Lomi , 21 Mar.2000 ( ZRC) ; 6 males, 4 females (brachypterous), Kalimantan Barat, Kabupaten Pontianak, Gg. Semahung , 27 Apr.1998 ( MZB, ZRC) ; 4 males, 4 females (brachypterous), Kalimantan Barat, Kabupaten Sanggau, abt. 249 km to Pontianank on Sosok–Sanggau Rd. , 26 Apr.1998 ( ZRC, NHMW) ; 1 male (macropterous); 4 males, 3 females (brachypterous), Kalimantan Barat, Kapuas, Kabupaten Sintang, abt. 2 – 3 km before Nanga Sayan , 24 Apr.1998 ( MZB, ZRC) .

Description of holotype, brachypterous male. – Body length 12.0 mm (range 11.5 – 13.0 mm, n = 18), head length 3.4 mm, head width at eyes 0.48 mm, width at metacetabula 0.71 mm, length of antennomere 2: 1.5 mm, length of mesotibia, 4.7 mm.

Colour: dorsum usually blackish or very dark brown, except base of head and some parts of thorax medium brown; venter black; laterotergites and lateral parts of sternites orange brown; antennae yellowish brown to nearly black; legs yellow to yellowish brown, more or less darker on apices of femora, tibiae and on tarsi; whitish stripe medianly on pronotum and laterally on thorax indistinct; each sternite anterolaterally and each laterotergite anteriorly with more or less distinct whitish spot (more frequently indistinct or absent); forewing brown with black veins, without white.

Structural characteristics: head long, slightly wider at eyes than at antennal tubercles (1.05 times), AO 1.9 times as long as PO; anteclypeus transverse ( Fig. 11 ), 0.5 times as long as wide, surface smooth, shining and strongly convex, anteriad slightly diverging sides, with anterior half medially depressed; maxillary plate narrow, elongate, with straight ventral margin, hardly covering base of gular lobe laterally; minimum dorsal distance between eyes 0.85 times of eye width; rostrum in resting position slightly surpassing posterior margin of eye; relative lengths of antennomeres ca. 0.5: 1.0: 2.8: 1.3.

Pronotum 0.48 times head length; metanotum 0.30 times head length; pronotum with few pits anteriorly weakly delimiting collar, and with small pits more or less arranged in longitudinal rows on pronotal lobe; few pits on acetabula; wing straps reaching anterior half of tergite 2, rarely reaching its posterior half; distance between mes- and metacetabula 2.0 times that between pro- and mesacetabula; relative lengths of leg segments (relative to mesotibia = 100): profemur – 82, protibia – 89, protarsus – 2+8+5, mesofemur – 96, mesotibia – 100, mesotarsus – 2+19+7, metafemur – 114 metatibia – 126; metatarsus – 2+15+6; ratio of mesotarsus: mesotibia 3.8 (range 3.5 – 3.9, n = 17); second mesotarsomere 2.9 times as long as third.

Abdomen elongate, narrow, 2.3 times as long as thorax along dorsal midline; fifth tergite 4.3 times as long as wide; tergite 7 posteriorly 1.5 times as wide as anteriorly, surface convex; connexival corner obtuse, without prominent pilosity; sternite 6 with long setae; sternite 7 ventrally with shallow depression in posterior 0.7 – 0.9, ventrolaterally with long and curved setae; segment 8 relatively long, and narrower than segment 7 in dorsal view, dorsomedially with short distal process directed straight caudad or slightly dorsocaudad, posteriorly with distinct ventromedian elevation bearing a pair of tufts of densely set short setae, these tufts located approximately in middle of the segment, ventrolaterally with shallow depression (Figs. 12,13).

Description of allotype, brachypterous female. – Similar to male, hardly longer because of curvature of abdomen; body length 13.2 mm (range 11.7 – 13.6 mm, n = 15), head length 3.8 mm, head width at eyes 0.53 mm, width at metacetabula 0.87 mm, length of antennomere 2: 1.5 mm, length of mesotibia 5.0 mm; laterotergites and lateral parts of sternites light orange; tergites medially or, usually, totally brown.

Structural characteristics: AO 2.0 times as long as PO; pronotum 0.5 times head length; metanotum 0.3 times head length; distance between mes- and metacetabula 1.9 times that between pro- and mesacetabula; wing straps reaching anterior half of tergite 2, rarely its posterior half; relative lengths of leg segments (relative to mesotibia = 100): profemur – 90, protibia – 91, protarsus – 2+9+5, mesofemur – 99, mesotibia – 100, mesotarsus – 2+19+6, metafemur – 120, metatibia – 122; metatarsus – 2+15+6; ratio of mesotarsus: mesotibia 3.6 (range 3.5 – 3.8, n = 15); second mesotarsomere 3.0 times as long as third.

Abdomen elongate, in dorsal view with slightly convex sides, strongly upcurved, curvature stronger in apical third; abdomen 2.1 times as long as thorax along dorsal midline; fifth tergite 3.3 times as long as wide; connexival margin without long setae; tergite 7 posteriorly 1.2 times as wide as anteriorly, surface convex (posteriorly stronger); tergite 8 small and directed ventrocaudad (more vendrad than caudad), with short distal spine which directed ventrocaudad at base and more caudad in distal half; sternite 7 only medially triangularly produced caudad, covering only base of gonocoxae ventrally, without depression ( Fig.14 ).

Description of macropterous male. – Body length 11.6 – 13.1 mm (n = 8, “morphotype” 12.4 mm), pronotum 0.5 times head length, distance between mes- and metacetabula 1.9 times that between pro- and mesacetabula; wings reaching distal half of tergite 5 to the base of tergite 6; ratio of mesotarsus: mesotibia 3.7 – 3.8 (n = 8, “morphotype” 3.7). Description of macropterous female. – Body length 12.8 – 13.4 mm (n = 8, “morphotype” 12.9 mm); most characteristics as in brachypterous male or macropterous male, respectively; distance between mes- and metacetabula 1.7 times that between pro- and mesacetabula; mesotarsus: mesotibia 3.7 – 3.9 (n = 8, “morphotype” 3.9); wings reaching basal half of tergite 5 to base of tergite 6.

Remarks. – See the Remarks of H. heoki paya, new subspecies.

Ecological notes. – This species is more common at the lowland forest streams, walking on water surface of slow flowing water or on shores. It is frequently collected with H. longicapitis and H. cracens in the lowland habitats, but with H. jaczewskii at the higher elevated rocky hill streams.

Distribution. – Borneo ( Fig.17).

· H. borneensis - H. brevitarsus

Etymology. – This species is dedicated to Dr. Tan Heok Hui (NUS), in recognition of his contribution to our knowledge of Hydrometra in the region.

Figures

Figs. 9-16. 9, Hydrometra borneensis, new species, male terminal abdomen, ventral view. 10, Hydrometra maidli Hungerford and Evans, male showing patch of setae on sternite 7. 11-14. Hydrometra heoki heoki, new species. 11, head, dorsal view, showing anteclypeus; 12, male terminal abdomen, lateral view; 13, male terminal abdomen, vental view; 14, female terminal abdomen, lateral view. 15, Hydrometra heoki paya, new species, male terminal abdomen, ventral view. 16, Hydrometra gilloglyi Polhemus and Polhemus, male terminal abdomen, ventral view.