Rhagovelia cheesmanae, 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 : 195-199

Rhagovelia cheesmanae new species

( Figs. 321–330 )

Type material examined. Holotype, wingless female: PAPUA NEW GUINEA, New Guinea, Central Prov. , Owen Stanley Range, Udabe River headwaters, 1.75 km. WNW of Woitape, 1615–1645 m., 8°32'02"S, 147°14'16"E, water temp. 16.5°C., 1 October 2003, 09:00–14:00 hrs., from margins of main river channel, CL 7247a, D. A. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, New Guinea, Central Prov.: 65 winged males, 46 winged females, 14 wingless males, 19 wingless females, same data as holotype, CL 7247a, D. A. Polhemus ( USNM, BPBM) ; 9 winged males, 5 winged females, 5 wingless males, 5 wingless females, same data as holotype except 8°32'03"S, 147°14'20"E, tributary creek entering main river channel, CL 7247b, D. A. Polhemus ( USNM, BPBM) ; 6 wingless males, 6 wingless females, Owen Stanley Range , Om Creek, trib. to upper Udabe River, 1.85 km. SSE of Woitape, 1585 m., 8°33'28"S, 147°15'22"E, water temp. 19 °C., 2 October 2003, 12:00–12:30 hrs., CL 7251, D. A. Polhemus ( USNM, BPBM) ; 35 winged males, 24 winged females, Owen Stanley Range , Mas River, 2.0 km. SW of Fane, 1235 m., 8°33'25"S, 147°04'04"E, water temp. 20 °C., 5 October 2003, 10:00–13:30 hrs., CL 7257, D. A. Polhemus ( USNM, BPBM) ; 2 winged males, 1 winged female, Owen Stanley Range , trib. to Mas River, 1.9 km. SW of Fane, 1220–1250 m., 8°33'33"S, 147°04'12"E, water temp. 20.5 °C., 5 October 2003, 10:45–12:30 hrs., CL 7258, D. A. Polhemus ( USNM, BPBM) ; 61 winged males, 45 winged females, 4 wingless males, 8 wingless females, Owen Stanley Range , Hane River, 1.8 km. SSE of Fane, 1310–1370 m., 8°34'00"S, 147°05'10"E, water temp. 19 °C., 3 October 2003, 10:30–13:30 hrs., CL 7253, D. A. Polhemus ( USNM, BPBM) ; 32 winged males, 48 winged females, 4 wingless males, 3 wingless females, 140 immatures, Owen Stanley Range , upper Mimani River, 1.70 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., from margins of main river channel, CL 7260a, D. A. Polhemus ( USNM, BPBM) .

Description

Wingless male: Size: Length = 2.30–2.50 mm (x = 2.43, n = 4); width = 1.30–1.40 mm (x = 1.33, n = 4). Wingless female, length = 3.30–3.70 mm (x = 3.66, n = 5); width = 1.70–1.90 mm, (x = 1.77, n = 5). Winged male (fully alate), length = 3.50–3.90 mm (x = 3.59, n = 4); width = 1.40–1.65 mm (x = 1.56, n = 4). Winged female (fully alate), length = 4.40–5.00 mm (x = 4.52, n = 5); width = 1.90–2.00 mm (x = 1.95, n = 5).

Color: Dorsal ground color dark blackish-grey, marked with pale yellow on basal antennae and acetabula, legs brown basally, predominantly shining black distally ( Fig. 321 ). Head dark blackish-grey; tylus, juga, rostrum and antennal tubercles dark brown; eyes dark red; frons and vertex set with scattered long erect black setae. Pronotum entirely dark blackish-grey, lacking small, transversely ovate, dark orange spot anteromedially behind head vertex, anterior lobe with faint silver pruinosity; surface bearing scattered long, erect black setae. Mesonotum, metanotum, and all abdominal tergites and connexival segments bearing scattered long, erect black setae, lacking shining, glabrous areas. Antennal segment I with basal one-fourth pale yellow, distal portion plus all of segments II–IV black. Legs predominantly shining black, except fore and hind coxae and trochanters yellowish-brown, middle coxae dark brown. Venter dark pruinose grey, all acetabula pale yellow, abdominal ventrites VII–IX with broad, shining brown areas centrally.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; head length 0.35, width 0.75; length of eye along inner margin 0.25, anterior/posterior interocular space, 0.25/0.45. Pronotum length along midline less than dorsal length of head, leaving mesonotum broadly exposed, length 0.25, width 1.15; mesonotum lacking foveae, length along midline 0.70; metanotum length along midline 0.05. Lengths of abdominal tergites I–VIII, respectively: 0.10: 0.10: 0.10: 0.10: 0.07: 0.10: 0.30: 0.10. Connexiva with margins of even width throughout, bowed outward, posterolateral angles not modified, separated by entire width of tergite VIII, posterolateral angles with a few scattered long, posteriorly-directed black setae but lacking setal tufts ( Fig. 321 ).

Entire dorsum and laterotergites covered with very short, fine, appressed pale pubescence, interspersed with scattered longer, erect black setae; 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; fore trochanter with a dense, tapering tuft of short black setae ventrally at apex, resembling a small spine; middle and hind trochanters lacking setal tufts, pegs or teeth; fore femur with ventral surface slightly flattened, bearing a single very long, slender black seta basally, and thick fringe of short, erect, pale setae along entire length; fore tibia bowed with distinct bend at two-thirds distance from base ( Fig. 325 ), dorsal face bearing long, erect, dark setae, lengths of these setae exceeding thickness of tibia, ventral face bearing very short erect pale setae and 7 long, black setae along interior curve of sharply bent section; middle femur slender and unmodified, with posterior margin bearing 8 erect, slender, straight black setae; middle tibia straight, cylindrical; hind femur very weakly incrassate, bearing a single small, sharp, slender black spine at one-third distance from base, followed distally by 2 much smaller sharp spines; hind tibia straight, unmodified, unarmed ( Fig. 326 ).

Venter lacking minute black denticles on ventral head or thorax; mesosternum weakly depressed centrally, bearing V-shaped line of erect gold setae with apex directed anterad, these setae set on a weak, posteriorly opening V-shaped carina that continues onto metasternum; metasternum very slightly tumescent; abdominal ventrite I angled into vertical orientation, ventrites II–VII horizontal, not carinate or otherwise sculptured; ventrites VIII–X slightly retracted into ventrite VII.

Paramere small, slender, crescent-shaped, posteroventral margin bearing a few short, stout setae, apex weakly notched ( Fig. 327 ). Proctiger small, compact; basolateral lobes not developed; distolateral lobes weakly developed, rounded; distal cone tapering, apex slightly angular ( Fig. 328 ).

Lengths of antennal segments I–IV: 0.55: 0.40: 0.45: 0.40.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 0.95: 0.90: 0.01: 0.02: 0.17; of middle leg, 1.30: 1.15: 0.10: 0.55: 0.70; of hind leg, 0.95: 1.35: 0.05: 0.10: 0.25.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: overall body size much larger; dorsum lacking long, erect, black setae; pronotum with small, transversely ovate, dark orange patch anteromedially behind head vertex, bounded laterally by pale silvery pruinose areas; mesonotum broadly tumescent and domed, posterior margin transversely truncate; metanotum and abdominal tergite I with a pair (1+1) of depressions to either side of the broadly tumescent longitudinal midline; abdominal tergites very broad in relation to lengths; proctiger shining black dorsally; connexiva broadly bowed outward ( Fig. 322 ); all trochanters lacking setal tufts or spines; fore tibia straight; hind femur unarmed; abdominal ventrite VII with a broad glabrous dark brown patch centrally; gonocoxae vertical, commissure not carinate; proctiger angled downward at less than 45° when viewed laterally.

Legs longer than in male, proportions as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.25: 1.25: 0.01: 0.04: 0.30; of middle leg, 1.15: 1.75: 0.10: 0.70: 0.85; of hind leg, 1.25: 1.75: 0.05: 0.40: 0.35.

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.50, length 1.30, completely covering meso- and metanotum, humeri enlarged, posterior apex angular, anterior margin bearing small, transversely ovate, dark orange patch anteromedially behind head vertex, bounded laterally by pale silvery pruinose areas; posterior pronotal lobe broadly domed, lacking obvious foveae, posterior margin broadly angular, bearing numerous long, semi-erect black setae; forewings uniformly dark brown, extending past apex of abdomen when intact, bearing 4 closed cells, consisting of two elongate cells in basal half of the wing followed by two much smaller distal cells of subequal size, all in basal half of the wing ( Fig. 323 ).

Winged female: Similar to wingless female in general structure and coloration, with following exceptions: body size larger, pronotum width 1.95, length 1.75, with humeri prominent ( Fig. 324 ).

Etymology. The name “cheesmanae ” honors G. Evelyn Cheesman for her pioneering entomological collections in New Guinea.

Distribution. Known only from eastern Papuan Peninsula of southeastern New Guinea ( Fig. 330 ). The species range as presently understood occupies the Owen Stanley Mountains area of freshwater endemism (Area 31) as delineated by D. Polhemus & Allen (2007).

Comparative notes. Rhagovelia cheesmanae is an upland species that can be separated from the other members of the R. grisea subgroup occurring in the EPCT region by its darker grey coloration ( Figs. 325, 326 ); the short and stout first antennal segment which is less than twice the length of the second ( Figs. 325, 326 ); the relatively short and broad body form in males, with the length less than twice the maximum width; and the strongly domed female mesoscutum. All of the coxae and trochanters are dark-colored in males, and the male hind tibia bears a group of closely spaced bristly black setae on the distal section of the anterior margin. The development of the cross veins defining the distal cells of the forewing is intraspecifically variable across long series, with either the inner or outer distal cell sometimes not fully defined.

Biological notes. Rhagovelia cheesmanae occurs at higher elevations than other R. caesius group species in the EPCT, with all collections having come from elevations between 500 and 1700 m. The type-locality along the Udabe River headwaters near Woitape (CL 7247) was a swift, clear, heavily shaded second-order river 4–6 m wide and 0.3–1.0 m deep, flowing in a bed of rocks and cobbles interspersed with a few large boulders, and bordered by slightly disturbed upland rain forest ( Figs. 329 ). Rhagovelia cheesmanae was abundant here, schooling along the channel margins.

On the Hane River near Fane (CL 7253), R. cheesmanae was again taken from a similar habitat, a swift, clear mountain creek 0.3–1.0 m wide and 0.3–1.3 m deep, flowing in a bed of boulders and cobbles. The stream was bordered by grasses near the small hydro intake that served the nearby mission station, changing over to undisturbed montane rain forest not far upstream.

Along the Mimani River near Dorobisoro (CL 7260), R. cheesmanae was collected from the margins of pools along this moderately large, swift, clear river, which flowed through a boulder-strewn bed with periodic runs over gravel and cobbles. Lying at 535 m, this is the lowest elevation at which the species has so far been found.

Figures

FIGS. 321–324. Rhagovelia cheesmanae n. sp., structural details; wingless and winged morphs; specimens from New Guinea, Udabe River, CL 7247. 321. Wingless male, dorsal habitus. 322. Wingless female, dorsal habitus. 323. Winged male, dorsal habitus. 324. Winged female, dorsal habitus.

FIGS. 325–328. Rhagovelia cheesmanae n. sp., structural details; specimens from New Guinea, Udabe River, CL 7247. 325. Male left foreleg, dorsal view, showing bowed shape to facilitate phoresy. 326. Male left hind leg, dorsal view. 327. Male left paramere, outer lateral view. 328. Male proctiger, dorsal view.

FIG. 329. The upper Udabe River near Woitape, Central Province, Papua New Guinea, CL 7247, type-locality for R. cheesmanae n. sp.

FIG. 330. Distributions of species in the R. grisea subgroup on eastern New Guinea and adjacent islands.