Ranatra rafflesi Tran & D. Polhemus, 2012 (Fig. 1C–E) Ranatra rafflesi Tran & D. Polhemus, 2012: 104–106 (type locality: Singapore). Material examined. MALAYSIA – Sarawak: 1 male (ZRC _ ENT00012970), Sarawak, Sg. Stuum Muda, coll. H. H. Tan, 2 September 1996, THH9694; 2 males, 1 female (ZRC _ ENT00012971–73), Sarawak, Batu Kawa–Matang area, coll. H. H. Tan, 13 January 1996, THH9601; 1 male (ZRC _ ENT00012974), Sarawak, Sibu, coll. H. H. Tan & R. Kerle, 3 March 1998, THH9811; 3 males, 1 female (ZRC _ ENT00012975–78), Sarawak, 10 km from Kuching, coll. H. H. Tan, 4 September 1995, THH9556; 1 male, 1 female (ZRC _ ENT00012979–80), Sarawak, Kuching to Matang road, coll. H. H. Tan, 14 January 1996, THH9608; 2 males, 4 females (ZRC _ ENT00012981–83), Sarawak, 8 km towards Gedong, from Serian – Sri Aman road, coll. H. H. Tan, 16 January 1996, THH9613; 2 males, 1 female (ZRC _ ENT00012984–86), Sarawak 92-42; 1 male, 2 females (ZRC _ ENT00012987–88), Sarawak, MK94-55; 1 male, 1 female (ZRC _ ENT00012989–90), Sarawak, blackwater ditch 2 km fr. Kuching, Mantang Batu Kawa Rd from aff. (on way to Kuching) T-junction, coll. K. Lim, 3 July 1992, 92-45. INDONESIA – Bintan: 1 male (ZRC.6.17711), P. Bintan, 47 km to Tg. Pinang, 1°06′38.1″N, 101°29′18.0″E, [coll. unknown], 27 April 1994, HH008; 1 male, 3 females (ZRC.6.17701), P. Bintan, 1°10′26.2″N, 104°27′28.3″E, upstream, [coll. unknown], 27 April 1994, HH003; 3 males, 4 females (ZRC _ ENT00012941–44), Pulau Bintan, coll. Y. Chia, June 1993, TT11; 4 males (ZRC _ ENT00012944–48), Pulau Bintan, coll. Y. Chia, June 1993, TT9; 3 males, 2 females (ZRC _ ENT00012949–52), Pulau Bintan, coll. Y. Chia, June 1993; 1 male (ZRC _ ENT00012953), Pulau Bintan, north, coll. H. H. Tan, 27 June 1995, THH9531. INDONESIA – Sumatra: 1 male (ZRC.6.17685), Sumatra, Jambi, Sg. Alai, [coll. unknown], 21 June 1995, JMB9511; 1 male, 5 females (ZRC _ ENT00012954–55), Sumatra, east Jambi, coll. H. H. Tan, 22 November 1996, THH96153; 2 males, 2 females (ZRC _ ENT00012956–58), Sumatra, east Jambi, coll. H. H. Tan, 22 November 1996, THH96154; 2 males, 1 female (ZRC _ ENT00012959–61), Sumatra, Jambi, Danau, Kamining nr. Kg. Transos, water pH 6.1, coll. M. Kottelat & H. H. Tan, 31 May 1994, MK94-38; 1 male (ZRC _ ENT00012962), Sumatra Selatan, clear water stream through rubber estate, along road to Sungei Merdak, 7 km into Desa Suka Jaya, coll. H. H. Tan, 11 December 2003, THH03-69; – Banka: 1 male (ZRC _ ENT00012963), Sumatra, Banka, between Kg. Kurau and Kg. Balilik, 25 km N. of Koba, coll. M. Kottelat et al., 3 March 1993, BANGKA 93-95. INDONESIA – Nias: 2 males, Southern Nias, surrounding of Telukdalam, coll. M. A. Jäch, 12 February 1990 (NHMW). INDONESIA – West Kalimantan: 4 males, 4 females (ZRC _ ENT00013054–58, 69–71), 2 nymphs, W. Kalimantan, Sg. Sekawi – Danau Sekawi, coll. Y. Y. Goh et al., 14 May 1998, GYY70 [with paramere of slender form]; 1 male (ZRC _ ENT00013059), W. Kalimantan, Danau Pantu, coll. Y. Y. Goh et al., 4 May 1998, GYY51 [with paramere of slender form]; 2 males, 1 female (ZRC _ ENT00013000–02), W. Kalimantan, btw. Sekadau and Sintang, coll. H. K. Lua, H. H. Tan & D. Wowor, 22 April 1998, LHK0371/ THH9842; 7 males, 5 females (ZRC _ ENT00013003–010), 2 nymphs, W. Kalimantan, Sintang, Sekadau–Sintang Rd., coll. H. K. Lua, H. H. Tan & D. Wowor, 22 April 1998, LHK0372/THH9843 [with variations in parameres: specimens ZRC_ENT00013003–04 with paramere of slender form, same as that in GYY70 sample; others intermediate between holotype and the slender form or same as holotype]; 1 male (ZRC _ ENT00013011), Kalimantan, Sanggau, along Sekadau–Sintang road, coll. H. K. Lua, H. H. Tan & D. Wowor, 25 April 1998, LHK0378; 1 male, 3 females (ZRC _ ENT00013012–13), 1 nymph, W. Kalimantan, Pontianak, Sg. Luar nr. Sg. Tayan, coll. H. K. Lua, H. H. Tan & D. Wowor, 26 April 1998, LHK380/THH9854; 9 males, 4 females (ZRC _ ENT00013014–23, 66–68), 2 nymphs, Kalimantan, Pontianak, Lobok Raundal nr. Sg. Tayan, coll. H. K. Lua, H. H. Tan & D. Wowor, 26 April 1998, LHK0381 [parameres: intermediate form between holotype and the slender form as that in GYY70 sample]; 6 males, 6 females (ZRC _ ENT00013024–30), 1 nymph, Kalimantan, Pontianak, Gg. Semahung, nr Pahuman, coll. H. K. Lua, H. H. Tan & D. Wowor, 27 April 1998, LHK0383/ THH9857 [paramere of intermediate form]; 3 males, 1 female (ZRC _ ENT00013031–34), Kalimantan, Pontianak, Sg. Belado, Gg. Kloncet, coll. H. K. Lua, H. H. Tan & D. Wowor, 28 April 1998, LHK0384; 7 males, 7 females (ZRC _ ENT00013035–42), Kalimantan, Pontianak, Anjungan ‘D’, coll. H. K. Lua, H. H. Tan & D. Wowor, 28 April 1998, LHK0385/THH9860 [paramere of intermediate form]; 6 males, 4 females (ZRC _ ENT00013043–49), Pontianak, Sg. Kepayan, Pontianak–Anjungan road, coll. H. K. Lua, H. H. Tan & D. Wowor, 29 April 1998, LHK0386 [some with parameres of intermediate form, others same as holotype]; 1 male (ZRC _ ENT00013050), W. Kalimantan, Pontianak, Anjungan, Sg. Jelimpo, coll. H. H. Tan & Y. Y. Goh, 28 April 1998, THH9859 [paramere of intermediate form]; 1 male (ZRC _ ENT00013051), W. Kalimantan, Desa Tekalong, coll. Y. Y. Goh et al., 8 May 1998, GYY62 [paramere of intermediate form]; – South Kalimantan: 1 male, 1 female (ZRC _ ENT00013052–53), Kalimantan Selatan, Batulicin basin; stream at Simpang Alok, along road from Batulicin to Mantewe, Desa Gunung Raya, coll. H. H. Tan et al., 14 September 2011, THH11-11 [paramere of intermediate form]; – East Kalimantan: 2 males, 3 females (ZRC _ ENT00013072– 76), 1 nymph, Kalimantan Timur, Mahakam basin, Taman Wisata Air Tejun, coll. H. H. Tan & D. Wowor, 11 November 1999, THH9976 [paramere of intermediate form]; 1 male, 1 female (ZRC _ ENT00013077–78), Kalimantan Timur, Mahakam basin, coll. H. H. Tan & D. Wowor, 11 November 1999, THH9977. Diagnosis. Body length: males 21.0–24.0, females 25.0–29.0; siphon length ca. 0.80–0.95× body length; lorum higher than clypeus; vertex higher than eye, with low conical tubercle; eye width ca. 1.0–1.1× interocular width; space between middle coxae about as wide as space between hind coxae; posterior margin of metasternum truncate, only slightly convex; basal part of fore femur about 1.6× as wide as distal part; hind femur, when folded back parallel to body, slightly surpassing apex of abdomen in males, reaching apex of abdomen in females; paramere tapering along distal third, apical hook evenly curved, tip of hook expanded, ventral margin with a broadly triangular tooth immediately basad of hook (Fig. 1C–E). Remarks. This species is closely related to Ranatra natunaensis by having similar paramere structures. Tran & Polhemus (2012) provided comparative notes for these two species. Our examination of numerous further specimens, as listed above, has revealed differences in the paramere structure within samples from the type locality, Singapore, as well as within some samples from other areas. Such variation of the type specimens (from Singapore and from Bintan and Batam of Indonesia) was not reported in the original description by Tran & Polhemus (2012). In the holotype, the width of the apical hook is slightly greater than the width of the middle part (Fig. 1C). In the “slender form” (Fig. 1E), the middle part and/or the distal constriction before the apical hook is sometimes more slender than that of the holotype, thus the width of the apical hook appears greater than the width of the middle part. The most slender form occurs in samples GYY70 and GYY51 from West Kalimantan, Borneo (Fig. 1E). These samples also exhibit some other differences from the type material of R. rafflesi, such as the space between the middle coxae being very narrow, and the ventral teeth on the fore femur being slightly smaller (so that the width of the femur across the larger tooth is slightly smaller than the maximum width of the femur in the basal half). Several other samples from Kalimantan, as noted in the Material examined section, contain both the most slender form of paramere (like those in samples GYY70 and GYY51), the typical form (same as the holotype), and also intermediate forms (Fig. 1D); however, the shape of the apical hook and the triangular sub-apical tooth of the paramere are consistent among these forms. The distance between the middle coxae is also variable, but always narrower than the distance between the hind coxae. Because these differences occur within localities, we treat them as intra-specific and intrapopulation variations. Distribution. Singapore, Borneo (Sarawak), and Indonesia (Bintan, Batam, and Sumatra) (Tran & Polhemus, 2012; Tran & Poggi, 2019). First records from Kalimantan (Borneo) and Nias Island.

{"references": ["Polhemus DA & Polhemus JT (2012) Notes on Ranatra (Heteroptera: Nepidae) from Burma and the Andaman Islands, with description of a new species. Entomologica Americana, 118 (1): 242 - 251.", "Tran AD & Polhemus DA (2012) Notes on Southeast Asian Ranatra (Heteroptera: Nepidae), with description of a new species from Singapore and neighbouring Indonesian islands. Raffles Bulletin of Zoology, 60 (1): 101 - 107.", "Tran AD & Poggi R (2019) The genus Ranatra Fabricius (Heteroptera: Nepidae) in Borneo, with a redescription of Ranatra spinifrons Montandon and the description of a new species. Zootaxa, 4555 (2): 236 - 246."]}

Published as part of Tran, A. D. & Zettel, H., 2021, Taxonomy of the Ranatra biroi group sensu Lansbury, 1972 (Nepomorpha: Nepidae), with descriptions of two new species, pp. 507-521 in Raffles Bulletin of Zoology 69 on pages 510-511, DOI: 10.26107/RBZ-2021-0068, http://zenodo.org/record/7174619