Ranatra spinifrons Montandon, 1905

Polhemus, Dan A. & Polhemus, John T., 2013, Guide To The Aquatic Heteroptera Of Singapore And Peninsular Malaysia. X. Infraorder Nepomorpha-Famlies Belostomatidae And Nepidae, Raffles Bulletin of Zoology 61 (1), pp. 25-45 : 35

Ranatra spinifrons Montandon, 1905

( Figs. 15, 16 )

Ranatra stali Montandon, 1905: 390 (in part)

Ranatra stali var. spinifrons Montandon, 1910: 166

Ranatra spinifrons Montandon, 1914: 124

Material examined. — MALAYSIA, Selangor: 1 male, North Selangor swamp forest, stream at 34 km. marker on road to Tanjung Malim , 6 Jun.1991, ZRC.6.15525, coll. ZRC 1991–1992 Zool. Honours Class ( ZRC) .

Diagnosis. — Male body length 34 mm; length of abdomen 22 mm, length of respiratory siphon 28 mm. Colouration, including legs, uniformly brown. Head with frons strongly tuberculate between the eyes. Anterior lobe of prothorax with a pair (1+1) of small, elevated nodules to either side of midline immediately behind head vertex; posterior lobe of prothorax with a pair (1+1) of roughly triangular tumescences widely separated on either side of midline; ventral prothorax with raised longitudinal carina on anterior half. Fore femur with single moderately small tooth near the midpoint of the margin adjacent to the infolded tibia; middle femur slightly shorter than hind femur, respective lengths 16.70/17.50; hind femur when folded back reaching to base of operculum. Male paramere with a broad, moderately deep incision subapically, separating a long, thick, apically truncate distal hook from an angulate subapical lobe ( Figs. 15, 16 ).

Distribution. — Originally described from two specimens, one taken in the Moluccas ( Ternate) and the other from Borneo ( Montandon, 1910), and not recorded since. The specimen listed below is the first record for Peninsular Malaysia.

Discussion. — This is a rare and unusual species that is easily recognized by the unique character state combination of a prominent tubercle on the head vertex coupled with a long respiratory siphon, and by the distinctively shaped male paramere ( Figs. 15, 16 ), which is most similar to that of R. stali Montandon from the Philippines.

Lansbury (1972), in his revision of Oriental Ranatra , did not figure R. spinifrons , nor did he examine either of the two specimens recorded in the literature. In his brief discussion, he indicates that he considered the Ternate specimen lost, whereas the Borneo specimen was still present in the Genoa Museum. We have not had the opportunity to examine either of these, and given the absence of comparative material have provisionally assigned the distinctive specimen from Selangor listed above to R. spinipes based on its salient features, but with the realization that it may eventually prove to represent yet another new species putatively allied to R. stali . In particular, the original description by Montandon (1910) states that the respiratory siphon in R. spinifrons is two-thirds as long as the abdomen, whereas in the Selangor specimen at hand the length of the siphon (28 mm) is longer than the length of the abdomen (22 mm), thereby raising some question as to whether this Peninsular Malaysian specimen is truly conspecific with those taken further to the east.

Figures

Figs. 11–18. Ranatra species, male left parameres, outer view with detail of distal hook. 11, 12, R. gracilis, specimen from Laos, Vientiane Prov. 13, 14, R. parmata, specimen from Indonesia, Sumbawa (CL 2172). 15, 16, R. spinifrons, specimen from Malaysia, Selangor. 17, 18, R. varipes, specimen from Laos, Khammouane Prov.