Anisops occipitalis Breddin, 1905

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 : 89

Anisops occipitalis Breddin, 1905

Anisops occipitalis Breddin, 1905 ; Brooks, 1951; (redescription); Lansbury, 1965; Fernando & Cheng, 1974.

Diagnosis. – Macropterous, pale yellowish to grey, somewhat fusiform, greatest width at the level of apex of scutellum.

Length, male 6.6-8.1, female 6.6-8.3; width, male 1.6-2.2 female 1.6-2.4. Width of head 0.8-0.9 times the humeral width of pronotum and 5-6.5 times the anterior width of vertex.

Male. In dorsal view, head anteriorly truncate to slightly rounded, vertex level with anterior margin of eyes. Synthlipsis wide, 0.4-0.5 times the anterior width of vertex. Rostral prong longer than third rostral segment, originating near its distal margin. Tylus slightly swollen, labrum covered with short hairs. Forefemur broadly rounded apically, dorsal margin with a wide shallow indentation in apical third. Tibial comb with about 20-25 teeth decreasing in width from base to apex.

Female. In dorsal view, head anteriorly truncate, vertex level with anterior margin of the eyes. Synthlipsis 0.5-0.7 times the anterior width of vertex. Tylus flat, labrum bare.

Brachypterous form, not recorded from Malaysia, Sumatra and Java. However, Lansbury (1965) suggested that A. leucotheca Esaki , occurring from the Solomon Isles to Samoa, may represent the brachypterous form of this species.

Remarks. – Usually recognizable by its length, intermediate between A. barbatus which is larger and the other species which are smaller. [Small females of A. barbatus may be of the same length as large females of A. occipitalis but they are broader, width 2.8 or more, whereas A. occipitalis females have a maximum width of 2.4. Females of the smaller species have a narrower synthlipsis].

Distribution. – From West Malaysia through Indonesia to Australia ( Lansbury, 1965). Fernando & Cheng (1974) and Fernando & Leong (1976) recorded this species colonizing ponds from Johor. In the ZRC there is a sample from Singapore [Bukit Timah Nature Reserve, 13 Dec.1996, coll. T. Wong, H. K. Lua et al., 3 males 3 females and a single female Singapore at light May 1992], first record for Singapore. In addition specimens from Johor, Melaka, Pahang and Perak.