Ochterus signatus, 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 : 347-349

Ochterus signatus , new species

( Figs. 2 , 10–12 , 31 )

Material examined. — Holotype, male, VIETNAM, Lam Dong Prov., tributary stream to main river at Suoi Vang hydro, 1430 m, 11°59'26"N, 108°22'06"E, water temp. 21°C., 18 May 1998, CL 3085, coll. J. T. Polhemus ( BPBM).

Paratypes: VIETNAM, Lam Dong Prov.: 5 males, 1 female, same data as holotype ( JTPC). Kontum Prov. : 1 male, stream 63 km. NE of Kontum on Hwy. 24, 1050 m, 14°36'14"N, 108°18'22"E, 6 Mar.2001, CL 4281, coll. J. T . Polhemus and P. Nguyen ( JTPC) . MALAYSIA, Perak: 1 male, waterfall and rocky stream 60 km W. of Jeli, 20 Aug.1985, CL 2081, coll. D. A. & J. T . Polhemus ( JTPC) .

Diagnosis. — Easily recognisable by the large, pale yellow patch on the posteromedial section of the pronotum, the large, orange-brown patches on the inner sections of each hemelytral corium ( Fig. 2 ), and the distinctive male genitalia ( Figs. 10–12 ).

Description. — Male. General form broadly ovate, body length 5.15–5.50, maximum width (across hemelytra) 2.87–3.00 ( Fig. 2 ). Colouration dark brown; anterolateral flanges of pronotum whitish-yellow; posterolateral angles of pronotum and extreme base of hemelytral embolar margin dark yellow; posteromedial area of pronotum broadly and transversely pale yellow; inner corial area of hemelytron adjacent to posterior half of embolium broadly orangebrown; scattered pruinose lavender markings as follows: small, transverse patches along posterolateral sections of pronotum immediately behind eyes, two pairs (2+2) of small irregular patches laterally on each side of pronotum, a pair (1+1) of roughly crescentic patches on anterior portion of pronotum to either side of midline around inner bases of calli, small, longitudinally elongate patch medially at anterior margin of scutellum, 7–8 small, irregular patches arranged symmetrically on clavus and corium of each hemelytron consisting of 3 large, roughly circular patches spaced equally along central portion of forewing margin plus 5 smaller patches on more inner sections of clavus and corium; scattered pruinose grey markings as follows: broadly on basal 1/3 of clavus, irregularly on adjacent inner corium along claval suture, irregularly along inner curve of embolium, small roughly circular patch immediately behind and inside of posterior terminus of embolium, irregularly along posterior margin of forewing membrane. Head shining black; eyes silvery; clypeus shining dark blackish brown, narrowly transversely dark yellow along anterior margin; labrum and rostrum both black basally, chestnut brown distally; antennae with segments I and II dark yellow, segments III and IV dark brown; thoracic venter dull pruinose blackish brown; abdominal venter orange-brown, infuscated centrally; legs pale yellowish-brown, fore coxae broadly marked with medium brown, fore femur with longitudinally elongate brown patch centrally on inner face, fore tibia with broad brown annulation on basal half, all tibiae with extreme bases and apices infuscated, hind tibiae bearing very small dark brown spots at bases of spines, all tarsi with apices of terminal segments infuscated.

Head glabrous, length (along midline as measured from directly above)/width (across eyes) = 0.35/1.50, angled downward at greater than 45° when viewed laterally; frons with coarse striations, these striations becoming somewhat finer and more numerous on clypeus, inner margins of eyes bordered by broad channels bearing numerous short, transverse striations ( Fig. 31 ); eyes large, protruding, projecting posterolaterally beyond vertex; antennae with segments I and II short, globose, segments III and IV slender, filiform, lengths of segments I–IV = 0.10, 0.12, 0.35, 0.30; rostrum long, length = 3.10, exceeding hind coxae and extending onto basal half of abdominal venter.

Pronotum length (midline)/width = 1.10/2.68, bearing numerous small 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 = 1.05/1.60, 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 set with scattered punctations, these punctations frequently pruinose; anterolateral embolar margin narrowly explanate; length of clavus along outside margin 1.80; membrane venation evident, defining 6 closed cells.

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 silvery 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 golden setae, these setae becoming more numerous distally; hind tibia with about 14 long, stout, semi-erect, spine-like golden 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 = 1.30/1.25/0.03/0.27; middle femur/tibia/tarsal 1/tarsal 2 = 1.40/1.30/0.03/0.27; hind femur/ tibia/tarsal 1/tarsal 2/tarsal 3 = 1.50/2.45/0.05/0.30/ 0.20.

Genital segment well retracted into abdomen; subgenital plate with V-shaped indentation medially on posterior margin. Pygophore with caudal tip quadrate, apex transverse, lateral lobes well removed from apex ( Fig. 12 ). Right paramere with head of moderate height, evenly domed and convex; appendices moderately long, nearly symmetrical, apices “boot-shaped”, indented to form two stout apical processes, one of these processes large, with tip rounded, the other smaller, with the tip serrate ( Fig. 11 ); paramere shaft stout, broadened distally ( Fig. 10 ).

Female. Similar to male in general structure and coloration, body length 5.50, maximum width (across hemelytra) 3.02. Head length (along midline as measured from directly above)/width (across eyes) = 0.55/1.50; lengths of antennal segments I–IV = 0.10, 0.08, 0.30, 0.30; rostrum length = 3.05, exceeding hind coxae and extending onto middle of abdominal venter. Pronotum length (midline)/width = 1.40/2.90. Scutellum length/width = 1.00/1.70. Hemelytra with length of clavus along outside margin 2.40. Lengths of leg segments as follows: fore femur/tibia/tarsal 1/tarsal 2 = 1.50/1.30/0.03/0.27; middle femur/tibia/tarsal 1/tarsal 2 = 1.70/1.30/0.04/0.36; hind femur/tibia/tarsal 1/tarsal 2/tarsal 3 = 1.90/2.70/0.01/0.30/0.20.

Diagnosis. — Similar to O. marginatus in having a yellow patch centrally on the posterior margin of the pronotum. Differs in having the alternating pale patches along the lateral hemelytral margins pruinose lavendar rather than dark yellow, in having more distinct and less diffuse lavender pruinose markings on the central hemelytra ( Fig. 3 ), and in the distinctive male genitalic structures ( Figs. 13–16 ).

Description. — Male. General form broadly ovate, body length 4.80, maximum width (across hemelytra) 2.60 ( Fig. 3 ). Colouration dark blackish-brown; anterolateral flanges of pronotum, extreme posterolateral margins of pronotum, and small, transverse, roughly rectangular patch on posteromedial Etymology. — The name “ signatus ” is derived from the Latin “ signum ”, meaning “mark”, and refers to the distinctive markings on the hemelytra of this species.

Distribution. — Peninsular Malaysia and Vietnam

Discussion. — The terminal section on the appendage of the male paramere in O. signatus most closely resembles the character state seen in O. stysi from Mauritius and O. seychellensis from Mahé (see Figs. 3, 4 in D. Polhemus & J. Polhemus, 2008), indicating that these insular Indian Ocean taxa are sister to a Southeast Asian stock.

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. 10–12. O. signatus, new species, male, structural details, specimen from Malaysia, Perak, CL 2081. 10, Male right paramere. 11, Superior appendage of right paramere. 12, Medial process of pygophore.

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. 13–16. O. pseudomarginatus, new species, male, structural details, specimen from Malaysia, Perak, CL 2078. 13, Male right paramere. 14, Superior appendage of right paramere. 15, Medial process of pygophore. 16, Endosoma.