Rhagovelia tufi, Polhemus, 2024

Polhemus, Dan A., 2024, Thirty-four new species of Rhagovelia (Heteroptera: Veliidae) from the East Papua Composite Terrane, far eastern New Guinea, Zootaxa 5400 (1), pp. 1-214 : 22-26

Rhagovelia tufi new species

( Figs. 16 , 35–39 , 40 , 62 )

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Northern (Oro) Prov., New Guinea, Kofure River , W. of Tufi , 0–45 m., 9°04'58"S, 149°16'39"E, water temp. 28° C., 24–25 January 2004, 11:30–13:30 hrs. (24 January) and 09:30–14:00 hrs. (25 January), CL 7304b, at base of bedrock wall along main river channel, D. A. Polhemus and J. T. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Northern (Oro) Prov., New Guinea: 5 wingless males, 6 wingless females, same data as holotype, D. A. and J. T. Polhemus ( USNM, BPBM) ; 2 winged males, 2 winged females, 3 wingless females, New Guinea, same data as preceding except CL 7304a, in pockets of water amid stones along margins of main river channel, D. A. and J. T. Polhemus ( USNM, BPBM) ; 1 winged male, 1 wingless male, 4 wingless females, New Guinea, same data as preceding except CL 7304c, tributary with waterfall, D. A. and J. T. Polhemus ( USNM, BPBM) .

Description.

Wingless male: Size: Length = 3.50–3.90 mm (x = 3.12, n = 4); width 1.30–1.40 mm (x = 1.35, n = 4). Wingless female, length = 3.70–3.90 mm (x = 3.80, n = 2), width = 1.40–1.50 (x = 1.42, n = 2). Winged male, length = 3.80–4.10 mm (x = 4.06, n = 2); width = 1.50–1.70 mm (x = 1.60, n = 2). Winged female, length = 3.90 mm (n = 1); width = 1.60 mm (n = 1).

Coloration: Dorsal ground color black, sparingly marked with dark yellow to orange-brown on basal antennae, anterior pronotum, connexiva and basal femora ( Fig. 35 ). Head black, tylus and antennal tubercles brown, jugae and basal rostrum dark yellow, rostrum fuscous ventromedially, piceous distally; eyes dark red. Pronotum black, with a transversely ovate dark orange-brown spot anteromedially behind vertex, this orange-brown coloration bounded by black laterally and overlain with faint silvery pruinosity, separated from area of similar orange-brown color on propleurae. Mesonotum, metanotum and all abdominal tergites black except for dark orange-brown patch posteromedially on tergite VII, abdominal tergites I–VI uniformly dull and lacking glabrous areas, tergite VII and VIII semi-shining; connexiva black on inner halves, dark orange-brown on outer halves, ventral faces orange-brown. Antennal segment I with basal one-fourth dark yellow, distal three-fourths plus all of segments II–IV black. Legs generally black dorsally except bases of fore and hind femora orange-brown; ventrally with trochanters, basal half of fore femur, basal two-thirds of hind femur dull yellowish brown. Venter mostly black, proacetabula dark yellow, margins of middle and hind acetabula dark orange-brown, abdominal ventrites I–VI dull black, ventrites VII–IX semi-shining orange-brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.40, width 0.80; length of eye along inner margin 0.35, anterior/posterior interocular space, 0.20/0.50. Pronotum short, width 0.95, length along midline 0.30, less than dorsal length of head, leaving mesonotum broadly exposed; mesonotum smooth, lacking deep foveae, humeri depressed, length 0.65. Metanotum barely exposed, length 0.10. Lengths of tergites I–VIII, respectively: 0.15: 0.20: 0.20: 0.20: 0.20: 0.30: 0.40: 0.30. Connexiva with margins of even width throughout, subparallel adjacent to abdominal tergites I–IV, then gradually convergent posteriorly adjacent to tergites V–VII, posterolateral angles not modified, separated by entire width of tergite VIII, bearing a few long, curving, dark setae.

Entire dorsum thickly covered with fine, appressed pale pubescence, intermixed with scattered longer, semi-erect, bristle-like black setae on lateral pronotum and mesonotum, and numerous more slender, semi-erect black setae on abdominal tergites; 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, regularly spaced long, slender, straight dark setae along posterior margins of fore and middle femora, and long pilose brown setae along posterior margin of hind femur, length of these long setae equal to or exceeding the thickness of the respective femora on which they occur; fore and middle trochanters lacking pegs or teeth; fore and middle femora and middle tibia with margins straight, not flattened or otherwise modified; fore tibia broadly flattened ventrally, longitudinally concave near apex adjacent to grasping comb; hind trochanter with 7 very small dark pegs ventrally; hind femur moderately incrassate, bearing two rows of teeth and pegs lying in area covered by infolded hind tibia, consisting of 8 tiny black pegs running from femoral base to about one-third the distance to distal apex, then bifurcating into ventral row of 7 small teeth of subequal size running to the distal femoral apex, and a dorsal row consisting of a moderately large, bent brown spine with a black tip, separated by a wide gap from another spine of similar size and coloration, this second long spine followed by followed by 5 much smaller black spines of decreasing size running to distal femoral apex ( Fig. 37 ); hind tibia straight, inner surface bearing a single row of 16 small, stout, black pegs of equal size.

Venter of head lacking black denticles; prosternum and adjacent inner propleurae bearing small black denticles; mesosternum slightly depressed centrally, margins of this depression bearing long, fine gold setae; metasternum broadly and gently tumid, with fine, erect pale setae laterally; abdominal venter set with short appressed pale setae intermixed with longer, fine, semi-erect pale setae laterally and posteromedially; basal abdominal ventrites highly sculptured, ventrite I lying in vertical orientation and bearing a very small, rounded bump centrally, remaining ventrites horizontal and all in similar plane, ventrite II with a sharply raised longitudinal carina medially, this carina continuing incipiently onto ventrites III and IV, ventrite V slightly swollen, unmodified, ventrite VI slightly flattened centrally, ventrite VII depressed and concave centrally, lateral margins of this central depression slightly raised, lacking setal fringe or tufts; ventrite VIII constricted basally, with a pair (1+1) of shallow, concave depressions to either side of weakly carinate longitudinal midline.

Male paramere shape elongate, dorsal margin broadly concave, ventral margin bilobate, basal lobe bearing numerous stout setae, central portion of paramere slightly constricted, distal portion expanded, apex broadly rounded ( Fig. 38 ). Male proctiger with basolateral lobes well developed, prominent, angular; distolateral lobes not developed; distal cone dome-shaped, apex blunt ( Fig. 39 ).

Lengths of antennal segments I–IV: 0.80: 0.45: 0.60: 0.55.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.05: 1.05: 0.02: 0.02: 0.25; of middle leg, 1.65: 1.15: 0.05: 0.45: 0.75; of hind leg, 1.60: 1.50: 0.04: 0.12: 0.29.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: long, semi-erect dark setae absent on abdominal tergites except for a few such setae centrally on tergite II; abdominal tergites I and II slightly domed and upwardly convex, tergites III–V slightly raised along their longitudinal midlines, raised central section of tergite III bearing small patch of short gold setae, remaining sections of all these tergites dull grey and lacking setae; connexival margins convergent posteriorly, angled more strongly inward adjacent to abdominal tergites I and IV, then converging more gradually and subparallel adjacent to tergites V–VII ( Fig. 36 ), posterolateral angles forming right angles when viewed laterally, bearing small, angular tufts of short, posteriorly-directed black setae at apices, these tufts inwardly convergent over basal section of abdominal tergite VIII when viewed dorsally; abdominal tergite VIII and proctiger angled downward at 45°, proctiger elongate; ventral surface of middle tibia slightly flattened; hind trochanter lacking small black pegs; hind femur only weakly incrassate, area along ventral midline in area covered by infolded hind tibia bearing a single spine row consisting of a single moderately long, slender, sharp, backwardly-angling black spine, followed by 4 much smaller spines of progressively decreasing size to femoral apex; hind tibiae straight, inner surface lacking teeth; ventral coloration predominantly dull blackish-grey, abdominal sternites VII–IX semi-shining brown; prosternum, inner proacetabula and proepisternum bearing numerous tiny black denticles, these denticles absent on jugae of head; all abdominal ventrites lying in similar horizontal plane, posterior margin of abdominal sternite VII unmodified; commissure of first gonocoxae forming a sharply raised longitudinal ventral carina.

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.60, length 1.60, completely covering meso- and metanotum, humeri enlarged, posterior apex angular, anterior margin with brown area centrally flanked to either side by pruinose grey areas laterally, foveae not evident; entire pronotum and hemelytra covered with short recumbent gold setae, intermixed along posterior pronotal margin with scattered semi-erect, curling, dark setae; forewings uniformly dark blackish-brown, bearing 3 closed cells, consisting of 2 elongate cells in basal half of the wing followed by a single smaller distal cell near the middle of the wing, set centrally between the posterior apices of the two basal cells. Legs with hind femur less incrassate than in wingless form but bearing similar armature; middle coxae chestnut brown.

Winged female: Similar to macropterous male in general structure, coloration, and wing form; pronotum width 1.60, length 1.65.

Etymology. The name “tufi ” is a noun in apposition, and refers to the type-locality near Tufi, Papua New Guinea.

Distribution. Southeastern New Guinea; endemic to the Papuan Peninsula ( Fig. 62 ). The species range as presently known occupies the Cape Nelson Peninsula area of freshwater endemism (Area 33) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia tufi is most similar to R. bowutu , with the two species occupying adjacent ranges on the north side of the Papuan Peninsula ( Fig. 62 ), and having male abdominal ventrite VII with a broad, shallow, longitudinally ovate depression without strongly raised margins (compare Figs. 16, 17 ). The male genitalia show differences between the two species, with concavity on the ventral margin of the paramere in R. tufi being more tightly curving and strongly incised, and the apical head of the paramere bearing a small knob ventrally in R. bowutu (compare Figs. 38 , 45 ). The basolateral lobes of the proctiger are also broader in R. tufi (compare Figs. 39 , 46 ). The female dorsal abdomen of R. tufi has a slightly raised longitudinal carina on tergites III–V which is lacking in R. bowutu , and male abdominal tergite VII bears a shiny chestnut brown patch posteromedially, whereas in R. bowutu tergite VII is uniformly shiny black.

Ecological notes. The Kofure River at the type-locality was a clear stream flowing in a bed of boulders, rocks, cobbles and sand, and occupying a shaded, steep-sided canyon cut into the volcanic formations of the Cape Nelson Peninsula ( Fig. 40 ). The bed profile consisted of alternating riffles about 0.15 m deep and pools 0.3–1.0 m deep, with the water faintly turbid from recent rains. The river was sampled from the head of its estuary upstream for over a kilometer, with both the gradient and the size of the bed substrate increasing gradually but steadily as one worked upstream.A number of narrow side canyons fed into the main river, and many of these ended in tight gorges with tall waterfalls flanked by wet bedrock faces. Rhagovelia tufi was found on pools at the bases of such bedrock faces, and in gently flowing pools along the margin of the main river channel, where it was taken in company with R. priori , a species in the R. papuensis group.

Figures

FIGS. 16–19. Species of the Rhagovelia tufi subgroup, male terminal abdomen, ventral view, showing structural variation on ventrites VII and VIII. 16. R. tufi n. sp., specimen from New Guinea, Kofure River, CL 7304; 17. R. bowutu n. sp., specimen from New Guinea, Kamiali, CL 7243; 18. R. obscura n. sp., specimen from New Guinea, Dorobisoro, CL 7264; 19. R. upalai n. sp., specimen from New Guinea, Alotau, CL 7163.

FIGS. 35–39. Rhagovelia tufi n. sp., structural details; specimens from New Guinea, Tufi area, Kofure River, CL 7304. 35. Wingless male, dorsal habitus. 36. Wingless female, dorsal habitus. 37. Male hind leg, dorsal view. 38. Male left paramere, outer lateral view. 39. Male proctiger, dorsal view.

FIG. 40. The midreach of the Kofure River upstream of its estuary, northwest of Tufi, Oro Prov., Papua New Guinea, CL 7304, type-locality for R. tufi n. sp. and habitat for R. priori Lansbury.

FIG. 62. Distributions of species in the R. tufi subgroup and R. aviavi n. sp. in eastern New Guinea.

FIGS. 41–46. Rhagovelia bowutu n. sp., structural details; specimens from New Guinea, Kamiali, Aleater River tributary, CL 7243. 41. Wingless male, dorsal habitus. 42. Wingless female, dorsal habitus. 43. Wingless male left hind femur, ventral view. 44. Wingless female left hind femur, ventral view. 45. Male left paramere, outer lateral view. 46. Male proctiger, dorsal view.