Anisops nasutus Fieber, 1851

Nieser, Nico, 2004, Guide To Aquatic Heteroptera Of Singapore And Peninsular Malaysia Iii. Pleidae And Notonectidae, Raffles Bulletin of Zoology 52 (1), pp. 79-96 : 87-88

Anisops nasutus Fieber, 1851

Anisops nasuta Fieber, 1851 ; Brooks, 1951 (redescription); Fernando & Cheng, 1974; Fernando & Leong, 1976.

Diagnosis. – Stramineous to greyish, slender, anteriorly nearly parallel-sided, posteriorly converging, widest just in front of the apex of scutellum.

Length, male 6.0-7.8, female 6.0-7.0; width, male 1.3-1.8, female 1.4-1.9.

Male. In dorsal view the head has a cephalic projection with a broadly indented apex, in lateral view less than half the total length of the frons anteriorly of eyes. In frontal view the tylus has a wide median depression appearing almost flat; the frons is narrowed in the middle and has dorsally a median oval depression bordered by a carina ( Fig. 20 ). Synthlipsis about one quarter the anterior width of vertex. Rostral prong slightly shorter than third rostral segment, originating near its proximal margin. Forefemur apically narrowed. Stridulatory comb on foretibia with about 14 teeth which are longest in the middle.

Female. In dorsal view the head is rounded anteriorly; the synthlipsis is one quarter to one third the anterior width of vertex. Tylus flat.

Brachypterous form unknown.

Remarks. – Males are easily recognized by the structure of the cephalic projection and the frons. Females are very similar to those of A. bouvieri and A kuroiwae although they are usually larger (length of females of A. nasutus 6.0-7.0, of A. bouvieri and A. kuroiwae 5.4-6.3).

Distribution. – Widespread from India through West Malaysia to southern China, and through Indonesia to Australia and Pacific islands (Nieser & Chen, 1991). Fernando & Cheng (1974) and Fernando & Leong (1976) recorded it from Melaka and Singapore. I have not seen additional Malayan specimens.

Figures

Figs. 18-20. Anisops male, head in frontal view; 19-20 rostrum removed. 18 A. niveus; 19 A. kuroiwae; 20 A. nasutus. t = tylus.