Anisops exiguus Horváth, 1919

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 : 86

Anisops exiguus Horváth, 1919

Anisops exigua Horváth, 1919 .

Anisops exigera - Brooks, 1951 (misspelling, redescription); Fernando & Cheng, 1974; Fernando & Leong, 1976.

Diagnosis. – Generally a small, sordid white, shiny species. Greatest width at pronotal humeri. Lateral margins of abdomen with hemielytra, anteriorly parallel, posteriorly converging.

Length, male 4.3-4.8, female 4.3-5.2; width, male and female 1.2-1.4.

In dorsal view the head is anteriorly truncate with vertex slightly indented. Width of head 0.8-0.9 times the humeral width of pronotum and about six times anterior width of vertex. Synthlipsis very narrow, one fifth to one eighth the anterior width of vertex. Labrum without specialized bristles. Male. Tylus slightly swollen with a smooth surface. Rostral prong slightly shorter than third rostral segment, originating in its proximal third ( Fig. 16 ). Forefemur apically narrowed. Stridulatory comb on foretibia with 9-11 teeth which are longest in the middle.

Female. Tylus flat.

Brachypterous form unknown.

Remarks. – Anisops exiguus is very similar to A. lansburyi . Males can be recognized by the rostral prong, which is short in A. exiguus and long in A. lansburyi ( Figs. 16, 17 ). In addition the stridulary comb on the foretibia although similar in the number and structure of its teeth, lacks the one or two small teeth present apically in A. lansburyi ( Fig. 21 ). Females of A. exiguus are comparatively broader than those of A. lansburyi but these species are difficult to distinguish in the female sex. (See also under A. niveus ).

Distribution. – A widespread species, recorded from Papua New Guinea, Malaysia, Vietnam and India ( Brooks, 1951; Lansbury 1964). Fernando & Cheng (1974) and Fernando & Leong (1976) recorded it from Kedah and Johor. In ZRC there are samples from Melaka, Selangor, Johor and Bukit Timah Nature Reserve, (13 Dec.1996, coll. T. Wong, H. K. Lua et al.), first record for Singapore. The species is apparently widespread in the Malay Peninsula but has been collected infrequently, and with only a few specimens in each sample.

Figures

Figs. 12-17. Anisops male, head in lateral view. 12 A. barbatus; 13 A. bouvieri; 14 A.tahitiensis; 15 A.kuroiwae; 16 A. exiguus; 17 A. lansburyi. p = rostral prong; t = tylus.

Figs. 21-23. Anisops, male, stridular comb. 21 A. lansburyi; 22 A. nigrolineatus; 23 A. tahitiensis.