Cercotmetus, Amyot & Serville, 1843

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 : 29

KEY TO THE SPECIES OF CERCOTMETUS OCCURRING IN SINGAPORE AND PENINSULAR MALAYSIA

(after Lansbury, 1973)

1. Small species for genus, body length (excluding siphon) 32–41 mm; vertex raised between the eyes, but lacking a prominent tubercle; middle femur shorter than prothorax; male paramere shape as in Fig. 4.................. C . brevipes brevipes Montandon

– Larger species, body length (excluding siphon) exceeding 46 mm; vertex bearing a prominent tubercle; middle femur longer than prothorax; male paramere not as above (see Figs. 5, 6 ) ...................................................................................................2

2. Very large species, body length (excluding siphon) 48–60 mm; mesosternum lacking a longitudinal keel; middle and hind femora with prominent tufts of long hairs ventrally at distal tips; posterior third of abdominal tergite VI raised and often very hairy; colouration usually dark blackish brown; female operculum of normal length, not projecting posteriorly beyond posterior apices of flanking ventral laterotergites; male paramere shape as in Fig. 5............................ C . compositus Montandon

– Moderately large species, body length (excluding siphon) 46–53 mm; mesosternum bearing a longitudinal keel; middle and hind femora lacking prominent tufts of long hairs ventrally at distal tips, at most with a few shorter hairs; posterior third of abdominal tergite VI weakly raised at most and lacking hairs; colouration usually light brown; female operculum very long, projecting posteriorly well beyond posterior apices of flanking ventral laterotergites; male paramere shape as in Fig. 6 .......... .................................................. C. asiaticus Amyot & Serville 1959, coll. unk. (ZRC); 1 male, swamp forest stream 61 km. N. of Johor Bharu on Mersing Road, 16 Oct.1986, CL 2220, coll. D. A. & J. T. Polhemus (JTPC). Pahang: 2 males, Ulu Rompin, Sungai Kinchin, second stream, 13 Jun.1989, coll. C. M. Yang (ZRC); 3 males, Ulu Rompin, Sungai Kinchin, first tributary (Sungai Jebong), south of base camp, 13 Jun.1989, coll. C. M. Yang & Y. H. Koo (ZRC); 1 male, Lata Iskander waterfall, Cameron Highlands road, 18 Aug.1985, CL 2074, coll. D. A. & J. T. Polhemus (JTPC); 2 females, Cheroh River 6 km. E. of Tapah, 18 Aug.1985, CL 2072, coll. D. A. & J. T. Polhemus (JTPC). Selangor: 1 male, Sungai Pelumut, Subang, 14 Mar.1964, coll. unk. (ZRC); 1 female, Sungai Belat, 26 km. from Kuantan, 15 May 1995, coll. B. Tan and G. Sumita, TG03 (ZRC). Negeri Sembilan: 1 male, Ulu Bahau, stream in rubber estate, 17 Mar.1964, coll. unk. (ZRC). Terengganu: 2 males, 3 females, stream at about Km 6 on road from Kuala Brang to Terengganu, 19 Mar.1992, coll. P. Ng, LHK180 (ZRC). Perak: 1 male, 1 female, Sungai Korbu at Jalong, 16 Feb.1997, coll. H. K. Lua, LHK0321 (ZRC); 2 males, 1 female, stream 58 km. S. of Grik, 19 Aug.1985, CL 2077, coll. D. A. & J. T. Polhemus (JTPC). Discussion. — In addition to the species keyed above, Fernando & Cheng (1974) listed Peninsular Malaysian records for Cercotmetus pilipes Dallas , a species known only from a single male holotype taken in Bhutan. Although we have not located the specimen in question, this species is not represented in the extensive Cercotmetus material from Peninsular Malaysia present in the ZRC collection. Based on the above, we consider these Malaysian records of C. pilipes implausible, and feel it likely that they represent misidentifications of C. compositus Montandon (see below).

Figures

Figs. 4–6. Cercotmetus species, male parameres. 4, C. brevipes, specimen fromVietnam,Quang Tri Prov.5, C. compositus, specimen from Malaysia, Johor (CL 2220). 6, C. asiaticus, specimen from Vietnam, Gia Lai Prov. (CL 4286).