Ranatra spinifrons Montandon, 1910

Tran, A. D. & Zettel, H., 2021, Taxonomic review of the Ranatra gracilis group sensu Lansbury, 1972 (Nepomorpha: Nepidae), with descriptions of four new species, Raffles Bulletin of Zoology 69, pp. 45-70 : 64-65

Ranatra spinifrons Montandon, 1910

Ranatra stali Montandon, 1905: 390–391 (in part).

Ranatra stali var. spinifrons Montandon, 1910b: 166 (type locality: Sarawak, Borneo ).

Ranatra spinifrons Montandon, 1910b . — Montandon, 1914: 124–125 (elevated to species rank). — Lansbury, 1972: 339 (notes). — Tran & Poggi, 2019: 237–241 (lectotype designation, redescription).

Additional material examined. BRUNEI: 2 females ( ZRC.6.18816), Belait District, Sg. Sepan (tributary to Sg. Ingei), in Kerangas forest , coll. Tan H.H., 11 May 1996 , THH9621; 1 female ( NHMW), Belait District, Sungai Ingei, forest pool near Base Camp , 04°09′15″N, 114°43′04″E, coll. Mayyer Ling, 14 June 2010 (34).

Diagnosis. Body length: males 30–33, females 33–36; ratio of siphon length: body length ca. 0.67; siphon index ca. 1.65×; lorum lower and clypeus without nodule dorsally; vertex with very prominent tubercle, height of tubercle about equal to eye size in lateral view; ratio of eye width: interocular width ca 1.1; hemelytra reaching mid-length of abdominal tergum VI; posterior margin of metasternum angularly emarginated, with sublateral grooves; fore femur on flexor side with a median tooth and a median carina, and with one small pre-apical tooth (in males) or a pair of small pre-apical teeth (in females); hind femur, when folded back parallel to body surpassing anterior half but not reaching posterior margin of abdominal sternum VI (in both sexes); paramere: strongly constricted at distal half before a broadly curved and slender apical hook, apex of hook narrowly rounded, ventral side before apical hook with large, sub-triangular process.

Remarks. The fore femur of males has one small but distinct pre-apical tooth, while that of females has a pair of small pre-apical teeth. This character in female specimens was overlooked in Tran & Poggi (2019). For other comparative notes, see Remarks under R. pangantihoni , new species. The syntype of R. spinifrons from Ternate and specimens from Peninsular Malaysia identified as R. spinifrons by D. Polhemus & J. Polhemus (2012) belong to separate unknown taxa, as already discussed in Tran & Poggi (2019: 241).

Distribution. Borneo: Sarawak and Brunei ( Tran & Poggi, 2019).