Ochterus singaporensis, Polhemus & Polhemus, 2012

Polhemus, Dan A. & Polhemus, John T., 2012, Guide To The Aquatic Heteroptera Of Singapore And Peninsular Malaysia. Ix. Infraorder Nepomorpha, Families Ochteridae And Gelastocoridae, Raffles Bulletin of Zoology 60 (2), pp. 343-359 : 351-353

Ochterus singaporensis , new species

( Figs. 4 , 17–20 , 34 )

Material examined. — Holotype, male, SINGAPORE, MacRitchie Catchment Reservoir, NS 123B #G (stream towards reservoir), 20 Apr.1994 ( ZRC) . Paratypes: SINGAPORE: 1 female, Bukit Timah forest , Lower Jungle Falls stream, 12 Oct.1973, coll. D. H. Murphy ( ZRC) ; 1 female, Bukit Timah Nature Reserve , Jungle Falls Valley, 100 m ., 12 Oct.1986, CL 2212, coll. D. A. & J. T . Polhemus ( JTPC) .

Diagnosis. — Recognised by its small size, with the body length of males less than 4.0 mm, and of females less than 5.0 mm; the yellowish-brown ground colour of the hemelytra, the relatively limited pruinose lavendar markings on the hemelytra ( Fig. 4 ), and the short, angulate appendages of the male right paramere ( Figs. 17, 18 ).

Description. — Male. General form broadly ovate, body length 3.70, maximum width (across hemelytra) 2.20 ( Fig. 4 ). Colouration orange-brown; head, pronotum and scutellum dark brown to black; narrowly along posterior margins of eyes, anterolateral flanges of pronotum, narrowly along extreme posterior margin of pronotum dark yellow; scattered pruinose lavender markings as follows: 4 small irregular patches arranged transversely across central portion of pronotum on lateral and posterior margins of calli; tiny patch basomedially on scutellum; 3 prominent, roughly circular patches equally spaced along central portion of outer forewing margin on each hemelytron with 2 on posterior half of embolium and one on posterior corium, 5–6 small, irregular patches arranged symmetrically on clavus and corium, entire wing membrane also irregularly flecked with such pruinosity; punctations of hemelytra black.

Head shining black; eyes silvery; ocelli bright red; clypeus shining black, anterior margin broadly and transversely dark orange-yellow, labrum dark orange-yellow basally, black distally, rostrum shining dark orange-yellow, with basal

rostrum long, length = 1.90, exceeding hind coxae and extending onto base of abdominal venter.

Pronotum length (midline)/width = 1.05/1.90, bearing numerous small pruinose punctations; anterior collar prominent, flat; anterolateral margins explanate, well demarcated from disk; calli barely tumescent; posterior margin multisinuate, posteriorly concave centrally above base of scutellum. Scutellum triangular, length/width = 0.75/1.15, weakly tumescent, bearing numerous small punctations centrally plus a row of slightly coarser, more closely spaced punctations along lateral margins. Hemelytra long, attaining tip of abdomen, with corium, clavus and embolium well defined, surfaces orange brown, flecked with lavendar and set with numerous black punctations, these punctations denser on embolium and basal portion of corium, sparse on posterior portion of corium; anterolateral embolar margin narrowly explanate; length of clavus along outside margin 1.55; membrane venation evident, defining 6 closed cells.

2.60, exceeding hind coxae and extending onto base of abdominal venter. Pronotum blackish-brown on anterior half, dark reddish-brown on posterior half, anterolateral margins Ventral surface of thorax smooth and pruinose, lacking patches of long, upright, golden setae; scattered tiny, dark punctations present on pro- and mesoepisterna, a single diagonal line of punctations present on each metepisternum; abdominal venter covered with very short, fine, appressed golden setae, this setal covering interrupted by ovate glabrous patches surrounding spiracles laterally on paratergites.

Legs with all segments covered by short, fine, recumbent pale setae; all coxae bearing long, pale setae ventrally; fore and middle trochanters and basal halves of fore and middle femora with very long, erect, slender, pale setae ventrally, remainder of ventral margins bearing moderate length, upright, slender, pale setae; hind femur broadly and gently bowed downward when viewed laterally; all tibiae bearing numerous short, bristly gold setae, these setae becoming more numerous distally; hind tibia with about 8 long, stout, semi-erect, spine-like gold setae on posterior margin, these setae more numerous on distal third of tibia; claws golden, gently curving, arolia long, exceeding length of claws when viewed laterally. Lengths of leg segments as follows: fore femur/tibia/tarsal 1/tarsal 2 = 0.90/0.80/0.02/0.28; middle femur/tibia/tarsal 1/tarsal 2 = 1.00/0.95/0.02/0.18; hind femur/ tibia/tarsal 1/tarsal 2 /tarsal 3 = 1.10/1.50/0.03/0.15/0.12.

Genital segment well retracted into abdomen; subgenital plate with V-shaped indentation medially on posterior margin. Pygophore with caudal tip slender, apex truncate, lateral lobes weakly produced ( Fig. 19 ). Right paramere with head not highly expanded, domed and convex; appendices of similar size, short, apices angulate, margins lacking serrations ( Fig. 18 ); paramere shaft uniformly slender, lacking lateral flanges ( Fig. 17 ); phallotheca with distal process slender, coiled, shape as in Fig. 20 .

Female. Similar to male in general structure and coloration, body length 4.70, maximum width (across hemelytra) 2.60. Head length (along midline as measured from directly above)/width (across eyes) = 0.35/1.50; lengths of antennal segments I–IV = 0.10, 0.10, 0.30, 0.30; rostrum length = explanate, pale yellow, length (midline)/width = 1.20/2.55. Scutellum dark reddish-brown, narrowly black along basal and lateral margins, length/width = 1.00/1.52. Hemelytra medium orange brown with numerous tiny dark punctations, length of clavus along outside margin 1.70. Lengths of leg segments as follows: fore femur/tibia/tarsal 1/tarsal 2 = 1.10/1.00/0.02/0.18; middle femur/tibia/tarsal 1/tarsal 2 = 1.30/1.10/0.02/0.18; hind femur/tibia/tarsal 1/tarsal 2/tarsal 3 = 1.40/2.00/0.05/0.25/0.20.

Etymology. — The name “ singaporensis ” refers to the type locality, the island of Singapore.

Distribution. — Known at present only from the island of Singapore

Discussion. — Ochterus singaporensis is a small, orangebrown species that is most similar in size and colouration to O. noualhieri , which occurs in the Malay Archipelago, and from which it may be separated by the structures of the male genitalia (compare Figs. 17–20 and 26–28 ). It may be separated from O. marginatus by its smaller size; predominantly orange-brown colouration; the absence of both a yellow patch posteromedially on the pronotum and obvious alternating yellow-and-black patches on the anterolateral margins of the hemelytra ( Fig. 4 ); possessesion of much stouter appendages on the male right paramere ( Figs. 17, 18 ); and in having the middle tibia shorter than the middle femur.

not expanded into a larger patch medially ( Fig. 21 ). Head with frons and clypeus bearing coarse striations, inner margins of eyes bordered by narrow channels, these channels lacking transverse striations except at extreme anterior ends ( Fig. 30 ). Male genitalia with right paramere with appendages of uneven length, the longer of these multidentate along inner margin ( Figs. 23, 24 ); male pygophore with medial process prominent, broadly angulate ( Fig. 25 ).

Distribution. — Originally described from Sumatra, and also recorded from the adjacent Greater Sunda Islands of Java and Bali ( Jaczewski, 1935), and subsequently from Celebes (Nieser & Chen, 1992). Previous records of this species from New Guinea ( Kormilev, 1971; Baehr, 1990b) represent misidentifications.

Discussion. — This is a moderate sized, rather rotund species, with a body length of 4.5–4.9 mm. The holotype came

Based on the structure of the appendages on the male right paramere, O. singaporensis appears to be most closely related to O. homorfos Nieser & Chen from Celebes, but may be separated from that species by the details of the male genitalic structures and its more orange-brown colouration.

Figures

Figs. 1–4. Ochterus species, colour photographs of dorsum. 1, O. marginatus (Latreille), specimen from Thailand, Chonburi Prov. 2, O. signatus, new species, specimen from Malaysia, Perak, CL 2081. 3, O. pseudomarginatus, new species, specimen from Malaysia, Pahang, CL 2072. 4, O. singaporensis, new species, specimen from Singapore, Bukit Timah.

Figs. 17–20. O. singaporensis, new species, male, structural details, specimen from Singapore, Bukit Timah. 17, Male right paramere. 18, Superior appendage of right paramere. 19, Medial process of pygophore. 20, Endosoma.

Figs. 29–34. Ochterus species, colour photographs of head, anterior view, showing pattern of striations on frons.29, O. marginatus (Latreille), female, specimen from Vietnam, Cao Bang Prov., CL 4368. 30, O. thienemanni Jaczewski, female, specimen from Indonesia, Bali Prov., CL 2170. 31, O. signatus, new species, female, specimen from Vietnam, Lam Dong Prov., CL3085. 32, O. pseudomarginatus, new species, female, specimen from Malaysia, Perak, CL 2078. 33, O. noualhieri Baehr, female, specimen from Indonesia, Sulawesi Utara Prov., CL 2114. 34, O. singaporensis, new species, male, specimen from Singapore, Bukit Timah.

Figs.26–28. O. noualhieri Baehr, male, structural details, specimen from Indonesia, Celebes, CL 2127. 26, Male right paramere. 27, Superior appendage of right paramere. 28, Medial process of pygophore.

Figs. 21–22. Ochterus species, colour photographs of dorsum. 21, O. thienemanni Jaczewski, specimen from Indonesia, Bali, CL 2170. 22, O. noualhieri Baehr, specimen from Indonesia, Celebes, CL 2127.

Figs. 23–25. O. thienemanni Jaczewski, male, structural details, specimen from Indonesia, Bali, CL 2170. 23, Male right paramere. 24, Superior appendage of right paramere. 25, Medial process of pygophore.