Rhagovelia bwagabwaga, 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 : 139-144

Rhagovelia bwagabwaga new species

( Figs. 207 , 234–240 )

Type Material examined. Holotype, wingless male: PAPUA NEW GUINEA, Milne Bay Prov., Louisiade Archipelago, Misima Island, south coast, Keyana Creek , above Bwagabwaga village , 305–335 m., 10°40'34"S, 152°40'45"E, water temp. 22.5 °C., 4 September 2002, 10:00–12:00 hrs., CL 7206, D. A. & J. T. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Milne Bay Prov., Louisiade Archipelago, Misima Island : 3 winged males, 1 winged female, 74 wingless males, 65 wingless females, 3 immatures, same data as holotype, CL 7206, D. A. & J. T. Polhemus ( USNM, BPBM) ; 3 winged males, 5 winged female, 19 wingless males, 17 wingless females, 12 immatures, south coast, Paek River at Bwagabwaga village , 0– 10 m., 10°41'11"S, 152°40'24"E, water temp. 24.6° C., 4 September 2002, 13:00–14:00 hrs., CL 7211, D. A. & J. T. Polhemus ( USNM, BPBM) ; 1 winged male, 14 wingless males, 9 wingless females, 3 immatures, south coast, Yaua Creek, above Bwagabwaga village , 230 m., 10°40'47"S, 152°40'26"E, water temp. 22.5° C., 4 September 2002, 09:00–09:30 hrs., CL 7205, D. A. & J. T. Polhemus ( USNM, BPBM) ; 2 winged males, 1 winged female, 3 wingless males, 3 wingless females, south coast, stream at Lowaga Bay, W. of Patnai village , 0 m., 10°41'41"S, 152°40'51"E, 4 September 2002, 12:00–12:30 hrs., CL 7209b, D. A. & J. T. Polhemus ( USNM, BPBM) ; 15 winged males, 20 winged females, 47 wingless males, 43 wingless females, north coast, Guwana Creek, near Nulia village , 15– 30 m., 10°39'23"S, 152°41'16"E, water temp. 22 °C., 3 September 2002, 10:00–12:00 hrs., CL 7201, D. A. & J. T. Polhemus ( USNM, BPBM) ; 9 winged males, 2 winged females, 16 wingless males, 7 wingless females, 6 immatures, north coast, Imaganina Creek, near Kakamwa village , 0– 5 m., 10°38'33"S, 152°43'30"E, water temp. 25.5° C., 3 September 2002, 12:30–13:30 hrs., CL 7202, D. A. & J. T. Polhemus ( USNM, BPBM) ; 1 winged male, 15 wingless males, 11 wingless females, 7 immatures, north coast, Ara Creek, near Ana village , 15– 30 m., 10°37'02"S, 152°47'34"E, water temp. 25° C., 3 September 2002, 15:00–16:00 hrs., CL 7204, D. A. & J. T. Polhemus ( USNM, BPBM) ;

Description

Wingless male: Size: Length = 3.00– 3.40 mm (x = 3.17, n = 5); width = 1.00– 1.20 mm (x = 1.10, n = 5). Wingless female, length = 3.00– 3.30 mm (x = 3.13, n = 5); width = 1.20–1.30 mm, (x = 1.26, n = 5). Winged male, length = 3.40–3.80 mm (x = xxx, n = 2); width = 1.40–1.50 mm (x = 1.45, n = 2). Winged female, length = 3.45–3.50 mm (x = 3.47, n = 2); width = 1.45–1.50 mm, (x = 1.47, n = 2).

Color: Dorsal ground color black, marked with pale orange on anterior pronotum and connexiva, pale yellow on basal antennae and legs ( Fig. 234 ). Head black; rostrum brown, piceous distally; eyes dark reddish black. Pronotum yellowish-orange on anterior one-third, black on posterior two-thirds, the pale anterior coloration overlain with silvery pruinosity and extending laterally and ventrally onto propleurae. Mesonotum, metanotum and abdominal tergites I–VI black, tergite VII dark brown, tergites I–VI uniformly dull and lacking shining areas, tergites VII and VIII shining, connexiva black on inner halves, dark orange on outer halves. Antennal segment I with basal one-third pale whitish yellow, distal half plus all of segments II–IV black. Legs generally black, with coxae, trochanters, basal half of fore femur, basal third of hind femur ventrally pale whitish yellow. Venter brown, with lower propleurae and all acetabula pale yellowish, abdominal ventrites VII–IX yellowish brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.30, width 0.75; length of eye along inner margin 0.30, anterior/posterior interocular space, 0.20/0.30. Pronotum lacking foveae, long, width 1.10, length along midline 0.90, greater than dorsal length of head, leaving mesonotum barely exposed as only a small, thin crescent behind posterior margin; mesonotum barely visible behind pronotum, metanotum moderately exposed, length at midline 0.15. Lengths of abdominal tergites I–VIII, respectively: 0.20: 0.25: 0.23: 0.20: 0.23: 0.25: 0.40: 0.30. Connexiva with margins of even width throughout, margins nearly straight and evenly convergent posteriorly, posterolateral angles not modified, separated by entire width of tergite VIII.

Entire dorsum and laterotergites covered with fine, appressed, pale pubescence, intermixed with scattered moderately short, semi-recumbent black setae on abdomen; legs and antennae thickly clothed with short, appressed, pale setae, with scattered long, erect black setae on anterodorsal faces of antennal segments I and II, anterior margins of all femora, and anterior margin of hind tibia; fore femur with 2 rows of slender, moderately long, evenly spaced black setae on along ventral margin; fore tibia with long, slender, slightly curving setae along anterior margin, intermixed with a thick fringe of moderately long, semi-recumbent pale setae; posterior and middle tibiae with scattered short, erect black setae; a few long, slender, pilose, pale brown setae present along posterior margin of hind femur; fore and middle trochanters lacking pegs or teeth; fore femur with dorsal margin broadly concave and depressed centrally; fore tibia slightly expanded and ventrally flattened on distal one-fourth; middle femora and tibiae with margins straight, not flattened or otherwise modified; hind trochanter bearing longitudinal row of 4 small dark pegs ventrally; hind femur moderately incrassate, bearing a single row of teeth in area covered by infolded hind tibia, consisting of approximately 15 tiny black pegs basally, followed by 12–14 longer brown teeth with a black apices, these teeth gradually increasing in size from mid-femur in an apical direction, with third tooth in series largest, then decreasing steadily in size toward apex of femur; hind tibia straight, inner surface bearing single row of about 15 small dark teeth, these teeth gradually increasing in size toward tibial apex ( Fig. 236 ).

Venter of head and thorax lacking small black denticles; mesosternum slightly depressed centrally, margins of this depression and adjacent lateral metasternum bearing long, fine gold setae; abdominal venter set with short appressed gold setae; basal abdominal ventrites highly sculptured, ventrite I lying in vertical orientation, remaining ventrites horizontal and all in similar plane, ventrite II with an acute longitudinal carina of V-shaped cross section medially, ventrites III–VI unmodified, ventrite VIII broadly and shallowly depressed centrally.

Male paramere moderately small, bean-shaped, bearing stout setae ventrally, apex rounded ( Fig. 237 ). Male proctiger with basolateral lobes only moderately developed, apices rounded; distolateral lobes well-developed, broadly rounded; distal cone dome-shaped, apex broadly rounded ( Fig. 238 ).

Lengths of antennal segments I–IV: 0.70: 0.45: 0.60: 0.45.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2 of fore leg, 1.10: 1:10: 0.01: 0.02: 0.22; of middle leg, 1.80: 1.40: 0.10: 0.60: 0.70; of hind leg, 1.65: 1.60: 0.05: 0.15: 0.3

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: abdominal tergites V–VII shining centrally;connexival margins strongly convergent posteriorly adjacent to abdominal tergites I–IV, then gradually convergent adjacent to tergites V–IX, margins infolded so as to cover lateral sections of tergites II–VII to progressively greater degrees in a posterior direction, connexival margins adjacent to tergites II–IV narrowed and glabrous, shining black in colour; posterolateral connexival angles acute, nearly touching over base of tergite VIII when viewed from above ( Fig. 235 ), bearing small, dense, acuminate tufts of moderately short black setae; abdominal tergite VIII and proctiger deflected downward approximately 30° from vertical, lacking tufts of black setae laterally; hind femur only weakly incrassate, posterior margin bearing a moderately large, acuminate black tooth at about two-thirds distance from the base, followed by 2–3 much smaller black teeth; hind tibia straight, inner surface lacking teeth or pegs; ventral coloration predominantly dark to medium brown, with lower propeurae and all acetabula pale yellowish; all abdominal ventrites lying in similar horizontal plane, ventrites I–IV with raised patches of fine, semi-recumbent gold setae in a band along longitudinal midline ( Fig. 207 ).

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.50, length 1.25, completely covering meso- and metanotum; anterior lobe dark yellow; humeri enlarged, slightly protrusive laterally; posterior pronotal lobe dark brown, surface behind transverse midline bearing numerous very small, deep foveae; wings long, reaching beyond tip of abdomen, coloration dark brown with inner basal margin narrowly yellowish brown, bearing 4 closed cells in basal two thirds of wing, consisting of two larger elongate basal cells followed by two smaller distal cells of with the outer distal cell slightly smaller, basal sections of anal, radial and subcostal veins bearing fine, raised black setae; hind femur not highly incrassate, spination similar to that of wingless male.

Winged female: Similar to winged male in general body form and coloration, pronotum width 1.45, length 1.25.

Etymology. The name “bwagabwaga ” is a noun in apposition, and refers to Bwagabwaga village on Misima Island, near which the type series was collected.

Distribution. Louisiade Archipelago; endemic to Misima Island ( Fig. 240 ). The species range as presently known occupies the Misima Island area of freshwater endemism (Area 37) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia bwagabwaga is an annectant taxon that possesses a mix of character states found in both the R. yela and R. loriae subgroups. It shares with R. yela and R. tagula the dense patches of thick black setae on the basal two female connexival segments, one of the the defining characters for the R. yela subgroup. However unlike these other two species it lacks a transverse fold centrally on the female connexiva ( Fig. 235 ), with the connexival margins adjacent to tergites II–IV instead being narrowed, glabrous, and shining black, a character state more typical of the R. loriae subgroup. In addition, female abdominal ventrites I–IV possess raised patches of fine, semi-recumbent gold along their longitudinal midlines ( Fig. 207 ), a character state also seen in the members of the R. loriae subgroup, which occur on the D'Entrecasteaux Islands to the west of Misima. The transverse depression of an abdominal ventrite posterior to these golden setal patches seen in certain members of the R. loriae subgroup is also present, but occurs on ventrite III, rather than ventrite IV.

At the species level, a distinctive character state in R. bwagabwaga is the broadly concave and centrally depressed ventral face of the male fore femur, which is not seen in other members of the R. yela or R. loriae subgroups. The female connexiva are also diagnostic, with acute posterolateral connexival angles that are closely convergent posteriorly, nearly meeting over base of tergite VIII when viewed from above ( Fig. 235 ), and bear small, dense, acuminate tufts of moderately short black setae.

Ecological notes. Rhagovelia bwagabwaga is the only Rhagovelia species so far collected on Misima, having been taken from rocky upland streams occupying eight separate catchments, at elevations ranging from sea level to 335 m, in a range of ecological settings. At Guwana Creek (CL 7201), Ara Creek (CL 7204), and the type-locality at Keyana Creek (CL 7206) the species occurred on swift, clear, rocky streams with relatively steep bed profiles ( Fig. 239 ). At the lower elevation sites of Imaganina Creek (CL 7202) and the Wala River (CL 7203) R. bwagabwaga occurred on riffles just above the heads of long, slow, deep terminal reach pools that formed behind cobble bars at the seaward termina of these streams, essentially at the limnetic to mixohaline interface. At Lowaga Bay the species was found on a stream emerging from a cave at the base of limestone cliffs (CL 7210), which formed a rocky creek flowing down to the bay.

Figures

FIGS. 203–208. Rhagovelia papuensis group, female ventral abdomen showing locations of depressions and patterns of setiferation. 203. Rhagovelia loriae n. sp.; specimen from New Guinea, Dorobisoro, CL 7260. 204. Rhagovelia guiagoila n. sp.; specimen from Basilaki Is., Kalawai River, CL 7294. 205. Rhagovelia basima n. sp.; specimen from Fergusson Is., Yaya River, CL 7178. 206. Rhagovelia elongata n. sp.; specimen from Goodenough Is., Matalamoia River, CL 7187. 207. Rhagovelia bwagabwaga n. sp.; specimen from Misima Is., Keyana Creek, CL 7206. 208. Rhagovelia priori n. sp.; specimen from New Guinea, Kofure River, CL 7304.

FIGS. 234–238. Rhagovelia bwagabwaga n. sp., structural details; specimens from Misima Is., Keyana Creek, CL 7206. 234. Wingless male, dorsal habitus. 235. Wingless female, dorsal habitus. 236. Male right hind leg, dorsal view. 237. Male left paramere, outer lateral view. 238. Male proctiger, dorsal view.

FIG. 239. Keyana Creek, Misima Is., Milne Bay Province, Papua New Guinea, CL 7206, type-locality for R. bwagabwaga n. sp.

FIG. 240. Distributions of species in the R. yela subgroup in the Louisiade Islands, and R. suloga on Woodlark Island.