Hydrometra heoki paya, Zettel & Yang, 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 : 396-398

Hydrometra heoki paya , new subspecies

( Fig. 15 )

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

Material examined. – Holotype - (brachypterous male): WEST MALAYSIA: Johor, Mersing, stream at 31 km to Mersing , 11 Mar.1998, coll. H.H. Tan et al. ( ZRC).

Paratypes – (all brachypterous, unless stated otherwise): 2 females (incl. allotype), 4 males (apterous), same data as holotype ( ZRC, NHMW); 1 female , Sg. Mupoh , 15 Oct.1992, coll. K. L. Yeo; 1 female , Gg. Panti foothills, 2 Dec.1998, coll. H. K.Lua ( ZRC); 1 male , Mersing, Sg. Batang Pinang, 9 May.1995 ( ZRC); 1 female ,

H. heoki heoki H. heoki paya

Mersing, 56 km off, 25 Mar.1998, coll. H. H. Tan et al. ( NHMW); 1 male (brachypterous), 1 female (macropterous, “morphotype”), Mersing , Sg. Batang Pinang tributary, 9 May.1995 ( ZRC) ; 4 males, 3 females, Sg. Selangi, 22 Apr.1992, coll. K. L. Yeo & C. Y. Chang ( ZRC, NHMW) .

Description of holotype, brachypterous male. – Body length 13.5 mm (range 12.6 – 13.5 mm, n = 13), head length 3.7 mm, head width at eyes 0.52 mm, width at metacetabula 0.80 mm, length of antennomere 2: 1.6 mm, length of mesotibia 5.2 mm.

Colour: dorsum medium to chocolate brown, mainly brown on head and terminalia; venter black; laterotergites and lateral parts of sternites orange brown; antennae yellowish brown, darker towards apex of each segment; legs yellow to yellowish brown, more or less darker on tarsi and apices of femora and tibiae whitish stripe medianly on pronotum and laterally indistinct on thorax; each sternite anterolaterally and each laterotergite anteriorly with more or less distinct whitish spot; forewing brown with black veins, without white.

Structural characteristics: head long, slightly wider at eyes than at antennal tubercles (1.05 times), AO 2.0 times as long as PO; anteclypeus transverse, 0.6 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 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 0.47 times head length; metanotum 0.30 times head length; pronotum with few pits anteriorly weakly delimiting collar, small pits more or less arranged in longitudinal rows on pronotal lobe; few pits on acetabula; wing straps reaching anterior half of tergite 2; distance between mes- and metacetabula 2.1 times that between pro- and mesacetabula; relative lengths of leg segments (relative to mesotibia = 100): profemur – 84, protibia – 90, protarsus – 2+8+5, mesofemur – 100, mesotibia – 100, mesotarsus – 2+16+6, metafemur – 119 metatibia – 121; metatarsus – 2+13+6; ratio of mesotarsus: mesotibia 4.2 (range 3.9 – 4.2, n = 13); second mesotarsomere 2.6 times as long as third.

Abdomen elongate, narrow, and weakly upcurved, 2.5 times as long as thorax along dorsal midline; fifth tergite 4.4 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 – 0.8, ventrolaterally with long and curved setae; sternite 8 with similar structure as H. heoki heoki new species, except the hair turfs are located behind middle of the segment ( Fig. 15 ).

Description of allotype, brachypterous female. – Similar to male, hardly longer because of curvature of abdomen; body length 13.7 mm (range 12.6 – 14.3 mm, n = 9), head length 3.9 mm, head width at eyes 0.54 mm, width at metacetabula 0.89 mm, length of antennomere 2: 1.5 mm, length of mesotibia 5.1 mm; laterotergites and lateral parts of sternites light orange; tergites medially or totally infuscated.

Structural characteristics: AO 2.1 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 (in one female surpassing middle of length); relative lengths of leg segments (relative to mesotibia = 100): profemur – 87, protibia – 90, protarsus – 2+8+5, mesofemur – 102, mesotibia – 100, mesotarsus – 2+18+7, metafemur – 124, metatibia – 129; metatarsus – 2+14+6; ratio of mesotarsus: mesotibia 3.8 (range 3.8 – 4.1, n = 10); second mesotarsomere 2.7 times as long as third.

Abdomen elongate, in dorsal view with slightly convex sides, strongly upcurved, curvature evenly increasing from base to apex; abdomen 2.0 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 as wide as anteriorly, surface convex (posteriorly stronger); tergite 8 small and directed ventrocaudad, with short distal spine, which is directed ventrocaudad at base and more caudad in distal half; sternite 7 only medially slightly and triangularly produced caudad, covering only base of gonocoxae ventrally, without depression.

Macropterous male. – Unknown.

Description of macropterous female. – Body length 13.7 mm (n = 1, “morphotype”); most characteristics as in brachypterous male or macropterous male, respectively; distance between mes- and metacetabula 1.8 times that between pro- and mesacetabula; mesotarsus: mesotibia 3.8 (n = 1, “morphotype”); wings reaching distal half of tergite 5.

Remarks. – Polhemus & Polhemus (1995) described H. gilloglyi as a very variable species that are regional differences in colour and curvature of the abdomen of the female. These authors regard the latter characteristic as a polymorphism similar with that described in H. longicapitis (where it is variable within populations). Based on large material now available for our study, three distinct, allopatric forms can be distinguished which differ in several persistent characteristics, including secondary sexual characteristics of the males (see Table 1, Figs. 12-16 ). However, two of these “forms”, those from Borneo and Johor, are more closely related to each other than to the typical H. gilloglyi , which is widely distributed on the Southeast Asian mainland. They are regarded as subspecific, because they show only minute differences in the terminalia of the males. Although an overlapping of the distribution areas of H. gilloglyi and H. heoki paya on the Malay Peninsula is unknown, numerous characteristics support the specific divergency of these two taxa, based on the type series of the new taxa, and numerous specimens of H. gilloglyi from Thailand, Vietnam and Perak in the northern Malay Peninsula.

Ecological Notes. – Not common. This subspecies is so far only known from the lowland swamp forests in Johor.

Distribution. – West Malaysia (Johor) ( Fig.17).

Etymology – The subspecies name “paya” derives from Malay and refers to the occurrence in freshwater swamps.

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.