Rhagovelia kiunga, Polhemus, 2024

Polhemus, Dan A., 2024, Two anomalous new species of Rhagovelia (Heteroptera: Veliidae) from southern New Guinea, Zootaxa 5474 (5), pp. 489-502 : 490-494

Rhagovelia kiunga n. sp.

( Figs. 1–7 , 9, 11 , 21 )

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Western Prov. , stream ~ 7 km. N. of Kiunga on Ok Tedi road, 30 m. [6°03'57"S, 141°18'28"E], 4 September 1983, CL 1775, D. A. Polhemus & J. T. Polhemus ( BPBM) . Paratypes: 14 wingless males (1 dissected), 12 wingless females, 22 immatures (not paratypes), same data as holotype, CL 1775, D. A. Polhemus ( USNM ex JTPC, BPBM) .

Description.

Wingless male:

Size: Length = 2.40–2.60 mm (x = 2.52, n = 5); width = 1.00– 1.20 mm (x = 1.10, n = 5).

Color: Dorsal ground dark blackish-grey overlain with a thin layer of pruinosity ( Fig. 1 ), with limited yellowish-orange on thorax and abdominal tergites; extreme antennal bases and bases of middle and hind legs white. Head uniformly black dorsally; jugae and rostrum medium brown except rostrum fuscous ventromedially, piceous distally; eyes silvery red. Pronotum black except for large, transversely rectangular yellowish-orange patch behind head vertex, this yellowish-orange coloration slightly exceeding width of vertex but not extending onto the propleura, posterior pronotal margin black. Mesonotum black, with prominent yellowish-orange patch centrally, extending along longitudinal midline but not reaching posterior margin, this patch roughly trapezoidal in shape, gradually tapering posteriorly. Metanotum and abdominal tergites I–VI black; shining areas visible in oblique light present as broadly transverse shining patch centrally on tergite I, transverse shining patches to either side of longitudinal midline on tergites II–V; paired, broad transverse shining patches present centrally on tergite VI; tergite VII black, shining, with roughly circular yellowish-orange patch centrally; abdominal tergites VIII and IX (= proctiger) black; connexiva matte black on inner sections, outer margins broadly dark brown, trending to orange-brown on posterior segments, shining when viewed in oblique light. Antennal segment I with basal one-third white, distal two-thirds plus all of segments II–IV dark brown. Legs generally dark brown to black, with fore coxae, inner base of middle coxae, hind coxae and trochanters, basal third of fore femur, and extreme base of hind femur pale whitish-brown. Venter predominantly matte black; proacetabula pale brown; mesosternum and adjacent mesopleural area plus broad posterior margins of hind acetabula pale yellow; abdominal ventrites VII and VIII orange-brown, shining.

Structural characters: Head moderately short, strongly declivant anteriorly when viewed laterally, with weakly impressed median line; length 0.35, width 0.75; length of eye along inner margin 0.35, eyes strongly convergent anteriorly ( Fig. 9 ), anterior/posterior interocular space, 0.05/0.40. Antennae with lengths of segments I: II: III: IV; 0.70: 0.35: 0.45: 0.50. Pronotum short, length along midline 0.15, less than dorsal length of head, leaving mesonotum broadly exposed, width 0.90; mesonotum smooth, lacking deep foveae, humeri depressed, length 0.50. Metanotum barely exposed, length 0.10. Lengths of abdominal tergites I–VIII, respectively: 0.12: 0.15: 0.15: 0.15: 0.14: 0.20: 0.25: 0.25. Connexiva with margins of even width throughout, bowed slightly outward, then gradually convergent posteriorly, posterolateral angles not modified, separated by entire width of tergite VIII, lacking setal tufts.

Entire dorsum and laterotergites thickly covered with fine, short, appressed pale pubescence, intermixed with scattered long, stiff, semi-erect black setae on lateral portions of metanotum; legs and antennae thickly clothed with short appressed pale setae, with scattered long, erect, bristly black setae on anterodorsal faces of antennal segments I and II, and anterior margins of all femora, long dark setae present on anterior margin of fore femur and posterior margins of fore and middle femora; a few evenly spaced, long pilose pale setae present along posterior margin of hind femur; all trochanters lacking pegs or teeth; fore and middle femora and middle tibia with margins straight, not flattened or otherwise modified; fore tibia slightly flattened ventrally on distal one-fourth, slightly channeled longitudinally adjacent to grasping comb; hind femur moderately incrassate, bearing two closely appressed parallel rows of teeth, ventral row lying in area covered by infolded hind tibia and consisting of a small spine and then a slightly longer spine near the base of the femur separated by a gap from approximately 10 small black teeth of relatively equal size originating about one-quarter distance from base of femur and running to distal apex, dorsal row commencing at about one-third distance from base of femur, with a very long slender, sharp black spine, then a shorter spine of similar form but half the length, followed by 10 progressively smaller black spines and teeth of similar shape running to femoral apex ( Fig. 3 ); hind tibia straight, inner surface bearing a row of about 16 small, dark, peg-like teeth running for entire length along longitudinal midline. Lengths of leg segments as follows: femur, tibia, tarsomere 1, tarsomere 2, tarsomere 3 of fore leg, 0.75: 0.80: 0.02: 0.02: 0.20; of middle leg, 1.25: 0.95: 0.02: 0.40: 0.65; of hind leg, 1.20: 1.05: 0.02: 0.02: 0.20.

Venter of head and thorax lacking small black denticles; mesosternum with a shallow, triangular depression centrally, margins of this depression bearing long, fine gold setae; metasternum not modified; abdominal ventrites bearing only a few scattered, short gold setae centrally along posterior margins, lateral portions of ventrite VII with numerous moderately long gold setae; abdominal ventrite very short, I lying in vertical orientation, ventrites II–IV slightly tumid centrally, remaining ventrites lacking carinae or depressions, ventrite VII bearing long gold setae laterally ( Fig. 11 ), such setae absent on ventrites VIII and IX, ventrite VIII not constricted basally.

Paramere shape tapering distally, basal section stout, bearing a dorsal shoulder, distal arm concave ventrally, gently curved dorsally, apex rounded ( Fig. 5 , 7 ); proctiger with basolateral lobes weakly developed, rounded, distolateral lobes also small, rounded ( Fig. 6 ).

Wingless female:

Size: Length = 2.90–3.00 mm (x = 2.92, n = 5); width = 1.10–1.25 mm, (x = 1.18, n = 5).

Similar to apterous male ( Fig. 2 ), with following exceptions: yellowish-orange markings more extensive with patches on pronotum and mesonotum similar to male, plus large, yellowish-orange patches on outer halves of all connexival segments, except basal segment narrowly margined with shining orange-brown; shining areas visible in oblique light present as broad patch centrally across most of tergite I, paired patches to either side of longitudinal midline on tergites II–IV, large transverse patches centrally on tergites V and VI, roughly quadrate patches centrally on tergites VII and VIII; connexival margins straight and of even width throughout, nearly parallel adjacent to tergites I–IV, then converging evenly to posterior apex of abdomen adjacent to tergites V–VII, all segments angling outward and not infolded, leaving all abdominal tergites visible in dorsal view, posterolateral angles not produced, lacking setal tufts; proctiger lying in horizontal orientation, gonocoxae angling upward at 45° when viewed laterally; hind femur with shape and armature similar to that of wingless male, hind tibia with very small, knob-like teeth along longitudinal midline; ventral coloration similar to that of wingless male except abdominal ventrite VII broadly yellowish-orange with basal third transversely medium brown; all abdominal ventrites lying in similar horizontal plane; gonocoxal commissure not carinate.

Winged male: Unknown.

Winged female: Unknown.

Etymology. The name “kiunga ” is a noun in apposition and refers to the town of Kiunga, Papua New Guinea, which lies near the type-locality.

Distribution. Southeastern New Guinea, Fly River basin ( Fig. 21 ). The species range as presently known occupies the Trans-Fly Coastal Lowland area of freshwater endemism (Area 27) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia kiunga can be quickly recognized within the New Guinea Rhagovelia biota by its small size, elongate-ovate body form, and the prominent orange patch centrally on the mesonotum in both sexes. It is similar in many respects to R. timikana , which occurs further to the west, but can be separated from that species by the following character states:

1) The male hind leg spine pattern is different from that of R. timikana , with two small spines usually present basally (compare Figs. 3 , 19 ), although this character can occasionally vary between individuals, and even between different legs on the same individual.

2) The male abdominal venter is less setiferous, with long gold setae present laterally only on ventrite VII, rather than on the lateral portions of ventrites VII–IX as in R. timikana (compare Figs. 11, 12 ).

3) The body ground coloration is dark pruinose-grey in R. kiunga , rather than black as seen in R. timikana , and the central orange patch on the male pronotum is larger and broader than in R. timikana (compare Figs. 1, 2 to 13, 14).

4) The orange patch on the central mesonotum is longitudinally rectangular in males of R. kiunga , versus triangular with a posteriorly-directed apex in R. timikana (compare Figs. 1 , 13 ).

5) The shapes of the male parameres easily separate the two species, with that R. kiunga bearing a dorsal shoulder basally, which is lacking in R. timikana (compare Figs. 7, 8 ).

For additional assessment of characters separating these two taxa see the discussion under R. timikana .

Ecological notes. The type-locality was a small, swiftly flowing rainforest stream, crossed by a newly improved road from Kiunga to Ningerum that was serving the Ok Tedi mine. A culvert had recently been constructed at this site, causing a small impoundment upstream of the road. The stream profile consisted of slow pools interspersed with swifter runs, with a benthic substrate of fine sediment. Rhagovelia kiunga was taken in a short, channelized, flowing section immediately upstream of the culvert. This recently disturbed habitat was probably not indicative of the true ecological preferences for this species, which are likely similar to those of R. timikana (see subsequent discussion under the latter species).

Figures

FIGURE 21. Distributions of species in the R. kiunga group in southern New Guinea.

FIGURES 1, 2. Rhagovelia kiunga n. sp. dorsal habitus; specimens from stream near Kiunga, Papua New Guinea, CL 1775. 1. Wingless male. 2. Wingless female.

FIGURES 3–6. Rhagovelia kiunga n. sp., structural details; specimens from stream near Kiunga, Papua New Guinea, CL 1775. 3. Male left hind leg, dorsal view. 4. Male left middle leg, dorsal view; 5. Male left paramere, outer lateral view. 6. Male proctiger, dorsal view.

FIGURES 7, 8. Rhagovelia species in the R. kiunga group, male right parameres, outer lateral views. 7. Rhagovelia kiunga n. sp. 8. Rhagovelia timikana n. sp.

FIGURES 9–12. Rhagovelia species in the R. kiunga group, structural details. Head in anterior view: 9. Rhagovelia kiunga n. sp. 10. Rhagovelia timikana n. sp. Male terminal abdomen, ventral view: 11. Rhagovelia kiunga n. sp. 12. Rhagovelia timikana n. sp.

FIGURES 15–19. Rhagovelia timikana n. sp., structural details; specimens from tributary to Iweka River, east of Timika, Indonesia, CL 7402. 15. Male left fore leg, ventral view. 16. Male left paramere, outer lateral view. 17. Male endosomal sclerites, left lateral view. 18. Male proctiger, dorsal view. 19. Male left hind leg, dorsal view.

FIGURES 13, 14. Rhagovelia timikana n. sp., dorsal habitus; specimens from tributary to Iweka River, east of Timika, Indonesia, CL 7402. 13. Wingless male. 14. Wingless female.