Rhagovelia obscura, 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 : 31-35

Rhagovelia obscura new species

( Figs. 18 , 48 –54, 62, 200)

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Central Prov. , New Guinea, Owen Stanley Range, upper Mimani River, 1.7 km. NE of Dorobisoro, 535 m., 9°27'25"S, 147°56'15"E, water temp. 23.5 °C., 7 October 2003, 13:00–15:00 hrs., CL 7260b, small flowing spring adjacent to main river channel, D. A. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Central Prov., New Guinea: 5 winged males, 1 winged female, 7 wingless males, 11 wingless females, same data as holotype, CL 7260b, D. A. Polhemus ( USNM, BPBM) ; 2 wingless males, 2 wingless females, Owen Stanley Range, trib. to upper Mimani River , 0.95 km. NE of Dorobisoro, 520 m., 9°27'27"S, 147°55'50"E, water temp. 23 °C., 7 October 2003, 11:30–12:00 hrs., CL 7259, D. A. Polhemus ( BPBM) ; 3 winged females, 3 wingless males, 1 wingless female, Owen Stanley Range, trib. to upper Mimani River , 0.8 km. W of Dorobisoro, 500 m., water temp. 23.5 °C., 9 October 2003, 08:30–12:30 hrs., 9°27'39.1"S, 147°54'56.2"E, CL 7264, D. A. Polhemus ( USNM, BPBM) ; 1 winged female, Owen Stanley Range, trib. to upper Mimani River , 2.7 km. NE of Dorobisoro, 580– 685 m., water temp. 21.5 °C., 8 October 2003, 09:30–12:30 hrs., 9°27'23"S, 147°57'03"E, CL 7262, D. A. Polhemus ( USNM) ; 6 wingless males, 5 wingless females, Yaniwe River at Tekadu , 300 m., water temp. 24° C., 21 January 2001, 12:00–16:30 hrs., 07°40'36"S, 146°33'05"E, 7157b, D. A. Polhemus ( BPBM, USNM) .

Description

Wingless male. Size: Length = 3.40–3.80 mm (x = 3.66, n = 5); width = 1.35–1.40 mm (x = 1.38, n = 5). Wingless female, length = 3.90–4.10 mm (x = 4.03, n = 5); width = 1.50–1.60 mm, (x = 1.56, n = 5). Winged male, length = 3.80–3.90 mm (x = 3.85, n = 2); width = 1.50–1.60 mm (x = 1.55, n = 2). Winged female, length = 4.10 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. 48 ). Head black, anterior portions of 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 not extending downward onto the propleurae, overlain with faint silvery pruinosity. Mesonotum, metanotum and all abdominal tergites black, abdominal tergites I–VI uniformly dull and lacking glabrous areas, tergites VII and VIII semi-shining; connexiva black on inner halves, dark orange-brown on outer halves, ventral faces dark orange-brown. Antennal segment I with basal one-third dark yellow, distal two-thirds plus all of segments II–IV black. Legs generally black dorsally, with coxae, fore and hind trochanters, basal one-fourth of fore femur posterodorsally dark yellow. Venter black, proacetabula dark yellow, margins of middle and hind acetabula dark orange-brown, abdominal ventrites I–VII dull black, ventrites VIII and IX semi-shining dark brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.40, width 0.85; length of eye along inner margin 0.35, anterior/posterior interocular space, 0.20/0.45. Pronotum short, width 1.00, length along midline 0.30, less than dorsal length of head, leaving mesonotum broadly exposed; mesonotum smooth, lacking deep foveae, humeri depressed, length 0.70. Metanotum barely exposed, length 0.20. Lengths of tergites I–VIII, respectively: 0.20: 0.20: 0.20: 0.15: 0.15: 0.20: 0.35: 0.40. Connexiva with margins of even width throughout, subparallel adjacent to abdominal tergites I–IV, than 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 black setae on lateral pronotum and mesonotum, and along posterior margins of all 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 flattened ventrally, longitudinally channelled near apex adjacent to grasping comb; hind trochanter with a longitudinal row of 4 very small dark pegs ventrally; hind femur moderately incrassate, bearing two rows of teeth and pegs lying in area covered by infolded hind tibia, ventral row consisting of 5–6 very small, sharp black teeth of subequal size commencing at about two-thirds distance from the femoral base and running to the distal femoral apex, dorsal row consisting of 10–12 very small, black teeth running from base of femur to one-third distance from base, followed by a moderately large brown spine with a black tip, separated from another spine of similar size and coloration by a wide gap containing two very small black teeth, this second long spine followed by followed by 5 much smaller black spines of decreasing size running to distal femoral apex; hind tibia straight, inner surface bearing a single row of 20 small, stout black teeth ( Fig. 50, 51 ).

Venter of head with juga and adjacent propleura bearing numerous 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 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 base of ventrite III, remainder of ventrite III and ventrites IV and V slightly swollen, unmodified, ventrite VI slightly flattened centrally, ventrite VII deeply depressed and concave centrally, lateral margins of this central depression strongly raised, posterior terminus of each raised margin bearing a small tuft of short, posteriorly-directed pale setae ( Fig. 18 ); ventrite VIII constricted basally, with a pair (1+1) of shallow, concave depressions to either side of weakly carinate longitudinal midline.

Male genitalia with paramere elongate, ventrally bilobate, basal section with ventral margin broadly rounded, bearing stiff setae, middle portion slightly constricted, then distal section expanded, posterior margin broadly curving, apex forming acute angle ( Fig. 52 ). Proctiger with basolateral lobes well developed, apices rounded; distolateral lobes very weakly developed, broadly rounded; distal cone triangular, with small, acute process at apex ( Fig. 53 ).

Lengths of antennal segments I–IV: 0.90: 0.45: 0.60: 0.55.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.10: 1.15: 0.02: 0.02: 0.30; of middle leg, 1.65: 1.25: 0.05: 0.60: 0.75; of hind leg, 1.45: 1.50: 0.05: 0.15: 0.35.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: long, semi-erect dark setae absent on posterior margins of abdominal tergites III–VII; abdominal tergites III–VII slightly raised along their longitudinal midlines, these raised central sections bearing patches of short gold setae, lateral sections of all these tergites dull grey and lacking setae; connexival margins convergent posteriorly, angled more strongly inward adjacent to abdominal tergites I‒IV, then converging more gradually and subparallel adjacent to tergites V–VII ( Fig. 49 ), 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 2 small, triangular, black teeth basally arising near ventral femoral midpoint, followed by 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; jugum and proepisternum bearing numerous tiny black denticles; 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 1.55, length 1.60, completely covering meso- and metanotum; anterior lobe with transverse ovate orange-brown patch along anterior margin in area behind head vertex, this patch bounded laterally by silvery pruinose areas, separated by dark coloration behind eyes from paler coloration on propleurae; humeri enlarged, slightly protrusive laterally; posterior pronotal lobe black, broadly domed, posterior half with small, obscure foveae, posterior margin broadly angular, bearing scattered long, gently curving, semi-erect black setae; forewings uniformly dark matte black, wing apices extending past apex of abdomen when intact, bearing 4 closed cells consisting of two elongate cells in basal half of wing followed by two smaller cells of subequal size distally near center of wing. Hind femur less incrassate than in wingless male.

Winged female: Similar to winged female in general structure and coloration, with following exceptions: body size larger, pronotum width 1.60, length 1.70, with humeri prominent.

Fig. 54. Tributary to the Mimani River west of Dorobisoro, Central Prov., Papua New Guinea, CL 7264, habitat for R. obscura n. sp. and R. mimani n. sp., and type-locality for R. loriae n. sp.

Etymology. The name “obscura ” is derived from the Latin obscurus, meaning “dark,” and refers to the blackish coloration of this species.

Distribution. Southeastern New Guinea; endemic to the Papuan Peninsula ( Fig. 62 ). The species range as presently known occupies the South Papuan Peninsula Foreland area of freshwater endemism (Area 30) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia obscura may be recognized by the form of male abdominal ventrite VII, which is strongly depressed and concave centrally, with the lateral margins of this central depression being strongly raised, and the posterior terminus of each raised margin bearing a small tuft of short, posteriorly-directed pale setae ( Fig. 18 ). Females have the connexival margins angled slightly inward adjacent to abdominal tergites IV and V, and small, sharp tufts of black setae at the apices which are also angled inward, with their apices meeting over the base of abdominal tergite VIII ( Fig. 49 ). The propleurae are also dark in both sexes.

Among the set of species occurring syntopically at the Dorobisoro type-locality along the Mimani River, this species might possibly be confused at first glance with R. peggiae Kirkaldy , but that latter species does not have male abdominal ventrite VII depressed; has more extensive orange-brown coloration on the male basal legs; has the female with the connexiva infolded and touching over abdominal tergite VII (compare Figs. 49 , 141 ); lacks black denticles on the jugae and propleurae; has the propleurae pale in both sexes; and has distinctively different male paramere and proctiger shapes (compare Figs. 52, 53 and 143, 144 ).

The male paramere of R. obscura is similar in general shape to that of R. upalai from the Milne Bay area further to the east, but more angular and pointed apically (compare Figs. 52 , 59 ). The male proctiger shape is also similar in both species, but the apex of the proctiger in R. obscura is distinctly produced to a small point (compare Figs. 53 , 60 ).

Ecological notes. Rhagovelia obscura was a rather localized and uncommon component of the diverse Rhagovelia assemblage present along the Mimani River and its tributaries at Dorobisoro (Figs. 54, 200), near the point where the river exits its deep mountain valley and enters the more open premontane foreland. At any given sampling site in this area captures of R. obscura were usually greatly outnumbered by the far more common R. mimani and R. loriae . At the type-locality, lying upstream of the village beyond the limit of the gardens, the species was taken on first order tributaries feeding into the main river. These small creeks had clear water running amid moss-covered metamorphic rocks and boulders, and waterfalls cascading over bedrock faces at the upper ends of the reaches sampled. All of these sites lay at elevations between 500 and 600 m., and only a single winged female was taken on other higher gradient tributaries sampled above 600 m.

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. 48–53. Rhagovelia obscura n. sp., structural details; specimens from New Guinea, Dorobisoro, Mimani River tributary, CL 7264. 48. Wingless male, dorsal habitus. 49. Wingless female, dorsal habitus. 50. Male right hind leg, posterior view. 51. Male right hind leg, dorsal view. 52. Male left paramere, outer lateral view. 53. Male proctiger, dorsal view.

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

FIGS. 140–144. Rhagovelia peggiae Kirkaldy, structural details; specimens from Dorobisoro, Papua New Guinea. 140. Wingless male, dorsal habitus. 141. Wingless female, dorsal habitus 127. Male right hind leg, posterior view. 128. Male left hind leg, ventral view; 140–142 from tributary to Mimani River, CL 7262. 143. Male left paramere, outer lateral view. 144. Male proctiger, dorsal view; 143–144 from tributary to Mimani River, CL 7263.

FIGS. 55–60. Rhagovelia upalai n. sp., structural details; specimens from New Guinea, Alotau, Upalai River, CL 7163. 55. Wingless male, dorsal habitus. 56. Wingless female, dorsal habitus. 57. Male right hind leg, posterior view. 58. Male right hind leg, dorsal view. 59. Male left paramere, outer lateral view. 60. Male proctiger, dorsal view.