Ranatra cardamomensis Zettel, Phauk, Kheam & Freitag, 2017

Tran, A. D. & Zettel, H., 2021, Taxonomy of the Ranatra biroi group sensu Lansbury, 1972 (Nepomorpha: Nepidae), with descriptions of two new species, Raffles Bulletin of Zoology 69, pp. 507-521 : 519

Ranatra cardamomensis Zettel, Phauk, Kheam & Freitag, 2017

( Fig. 4B, C )

Ranatra cardamomensis Zettel, Phauk, Kheam & Freitag, 2017: 36–39 (type locality: Cardamom Mountains , Koh Kong, Cambodia).

Type material examined. Holotype (male) and paratypes (4 males, 4 females) [note that the number of male/female paratypes is different in Zettel et al. (2017): 5 males, 3 females], “ Cambodia. Krâvanh Mnts, Koh Kong Prov., vic. Tatai , Tatai Riv., 21– 26.12.2015, 11°35′27″N, 103°5′44″E, Martynov A.V. leg.” ( NHMW, CFD, CEI, ZRC) . Paratypes (1 male, 2 female), “ Cambodia, Cardamom Mnts. Koh Kong Prov., vic. Chi Phat vill. –trib. Piphot Riv., 17–0.12.15, 11°19′13″N –23′12″N, 103°27′52″E –32′34″E, Martynov A.V. leg.” ( NHMW) .

Additional material examined. INDONESIA – Riau: 1 male, 1 female ( ZRC _ ENT00013061–62 ), Natuna, Pulau Bunguran, Sungei Segeram, Kecamatam Ranai, coll. D. Wowor et al., 18 March 2002, EA-DW11 [previously det. as “ cf. natunaensis ” in Tran & Yang, 2004] .

THAILAND: 1 male ( ZRC _ ENT00013063 ), Songkla Prov. , Nam Tok Khao Chong, coll. H. K. Lua, 26 October 1998, LHK0410 .

Diagnosis (adapted from Zettel et al., 2017). Body length: males 19.9–22.5, females 22.0–23.7; siphon length ca. 0.85–0.95× body length; lorum lower than clypeus; vertex higher than eye, with low conical tubercle; eye width ca. 0.95–1.00× interocular width; space between middle coxae about as wide as space between hind coxae; posterior margin of metasternum slightly convex; hind femur, when folded back parallel to body, surpassing anterior half to reaching posterior third of operculum (in males) or just to anterior third of operculum (in females); paramere ( Fig. 4B, C ) relatively broad medially then tapering at distal third, apical hook evenly curved, tip of hook rounded, slightly expanded, ventral margin right before hook with a low, broad elevation.

Remarks. Tran & Yang (2004) examined some specimens collected from Natuna Island and considered that they could be R. natunaensis . In this study, after comparing these specimens with the type specimens of R. cardamomensis , we find no distinct difference between them, except that the hind femora of specimens from Natuna are slightly longer, clearly surpassing the apex of the operculum (in males) or just reaching it (in females). In type specimens of R. cardamomensis , the hind femur of the male reaches to the posterior third or quarter of the operculum, whereas in females it is more variable, from reaching just to midlength or slightly surpassing the apex of the operculum. The parameres are identical (compare Fig. 4B with Zettel et al., 2017: fig. 13). Thus, these specimens are now confirmed as R. cardamomensis and are first reports of this species outside Cambodia.

We have also encountered a male specimen, collected from southern Thailand, which highly resembles the type specimens of R. cardamomensis . It has only a few small differences from the type specimens as follows: the posterior margin of the metasternum is rounded (in type specimens, it is convex but not rounded); the middle femur is slightly shorter, only reaching the anterior third of the operculum (in male type specimens, it reaches its mid-length); the hind femur is slightly longer, just surpassing the apex of the operculum (in male type specimens, it is variable, reaching the posterior third or quarter); and the paramere ( Fig. 4C ) is slightly more slender, with its dorsal margin slightly concave before the apical hook, which is slightly more slender (compare with Zettel et al., 2017: fig. 13). However, with only one specimen available, we cannot determine if these differences are reliable for distinguishing it as another species. Thus, we provisionally consider this specimen to be conspecific with R. cardamomensis .

Distribution. Cambodia ( Zettel et al., 2017); first records for Indonesia (Natuna Island) and southern Thailand.

Figures

Fig. 4. Parameres of Ranatra species. A, R. longipes longipes, from Brunei; B, R. cardamomensis, from Natuna Island (ZRC_ ENT00013061); C, R. cardamomensis, from southern Thailand (ZRC_ENT00013063). B, C same scale. Note that the paramere hook of the Thai specimen (Fig. 4C) recurved further after being dry-mounted from an alcohol-preserved specimen; while still in alcohol, the apex was same as that in the type specimens.