Rhagovelia grisea, 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 : 189-192

Rhagovelia grisea new species

( Figs. 310–315 , 330 )

Type material examined. Holotype, wingless female: PAPUA NEW GUINEA, New Guinea, Milne Bay Prov., Watuti River at Mila village , Sagarai River basin, 90 m., 10°29'57"S, 150°17'27"E, water temp. 30° C., 7 April 2002, 13:30–16:00 hrs., CL 7166, D. A. Polhemus and J. T. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, New Guinea, Milne Bay Prov.: 332 wingless males, 332 wingless females, 9 immatures, same data as holotype, CL 7166, D.A. Polhemus and J. T. Polhemus ( USNM, BPBM) ; 203 wingless males, 190 wingless females, 2 immatures, Gumini River at road bridge, SW of Alotau, 15 m., 10°19'08"S, 150°14'07"E, water temp. 30° C. (main channel), 28° C. (shaded side pools), 21 January 2004, 10:30–14:00 hrs., CL 7174, D. A. Polhemus and J. T. Polhemus ( USNM, BPBM) ; 15 winged males, 22 winged females, 29 wingless males, 26 wingless females, Muguwe Creek , W. of Naura, 16 mi. W. of Alotau, 70 m., 10°17'20"S, 150°12'10"E, water temp. 25.5° C., 9 April 2002, 10:00–11:30 hrs., CL 7169, D. A. Polhemus and J. T. Polhemus ( USNM, BPBM) .

Description

Wingless male: Size: Length = 2.40–2.60 mm (x = 2.51, n = 5); width = 1.10–1.30 mm (x = 1.18, n = 5). Wingless female, length = 3.10–3.40 mm (x = 3.22, n = 5); width = 1.50–1.80 mm (x = 1.66, n = 5). Winged male (fully alate), length = 3.00 mm (n = 1); width = 1.40 mm (n = 1). Winged female (fully alate), length = 3.60 mm (n = 1); width = 1.60 mm (n = 1).

Color: Dorsal ground color dark pruinose grey, marked with dull yellow on basal antennae and legs, and dark orange centrally on anterior pronotum; legs predominantly shining black ( Fig. 316 ). Head dark pruinose grey; tylus, juga, rostrum and antennal sockets dark brown; eyes silver; frons and vertex set with scattered long erect black setae. Pronotum dark pruinose grey, with small, transversely ovate, dark orange spot anteromedially behind head vertex, this orange coloration not extending onto the propleura; surface bearing scattered long, erect black setae. Mesonotum, metanotum, and all abdominal tergites and connexiva dark pruinose grey, surfaces bearing scattered long, erect black setae, lacking shining, glabrous areas.Antennal segment I with basal one-fourth dark yellow, distal portion plus all of segments II–IV black. Legs predominantly black, except fore and hind coxae and trochanters yellowish-brown. Venter pruinose grey, all acetabula dark yellow on ventral margins, abdominal ventrites VII–IX shining brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; head length 0.35, width 0.80; 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 0.90; mesonotum lacking foveae, length along midline 0.75; metanotum length along midline 0.05. Lengths of abdominal tergites I–VIII, respectively: 0.10: 0.13: 0.12: 0.12: 0.10: 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 lacking setal tufts ( Fig. 316 ).

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 tuft of short black setae ventrally at apex; middle and hind trochanters lacking setal tufts, pegs or teeth; fore femur with ventral surface flattened, bearing a single very long, slender black seta basally, and thick fringe of short, erect, pale setae along entire length; fore tibia bowed, dorsal face bearing long, erect, dark setae, lengths of these setae exceeding thickness of tibia, ventral face bearing very short erect pale setae; middle femur slender and unmodified, with posterior margin bearing 10–12 erect, bristly black setae; middle tibia straight, cylindrical; hind femur very weakly incrassate, lacking spines; hind tibia straight, unmodified, unarmed ( Fig. 318 ).

Venter lacking minute black denticles on ventral head or thorax; mesosternum weakly depressed centrally, bearing erect gold setae in a V-shaped pattern with apex directed anterad; metasternum very slightly tumescent; abdominal ventrites I–VII horizontal, not carinate or otherwise sculptured; ventrites VIII–X strongly narrowed.

Male paramere slender, gently curving, bearing short, stout setae ventrally on apical half, overall form crescent-shaped, apex broadly rounded ( Fig. 320 ). Male proctiger small, compact, heavily sclerotized, overall form subtrapezoidal, lateral margins gradually convergent posteriorly; basolateral lobes lobes small, broadly angular; distolateral lobes not developed; distal cone with posterior margin broadly angular ( Fig. 319 ).

Lengths of antennal segments I–IV: 0.90: 0.50: 0.45: 0.40.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 0.75: 1.00: 0.01: 0.02: 0.15; of middle leg, 1.80: 1.35: 0.10: 0.70: 0.80; of hind leg, 1.30: 1.90: 0.05: 0.20: 0.30.

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; mesonotum broadly tumescent and domed, posteriorly bilobate; metanotum and abdominal tergite I with a pair (1+1) of depressions to either side of broadly tumescent longitudinal midline; abdominal tergites very broad in relation to lengths; proctiger shining black dorsally; connexiva broadly bowed outward ( Fig. 317 ); all trochanters lacking setal tufts or spines; abdominal ventrite VII with a broad glabrous dark brown patch centrally, a small pale mark present in center of posterior margin at longitudinal midline; gonocoxae vertical, commissure not carinate; proctiger angled downward at 45° when viewed laterally. Legs longer than in male, proportions as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.00: 1.20: 0.01: 0.02: 0.30; of middle leg, 1.65: 1.15: 0.10: 0.75: 0.55; of hind leg, 1.25: 1.15: 0.05: 0.15: 0.25.

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.40, length 1.25, completely covering meso- and metanotum, humeri enlarged, anterior lobe 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 scattered 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.

Winged female: Similar to wingless female in general structure and coloration, with following exceptions: body size larger, pronotum width 1.60, length 1.50, with humeri prominent.

Etymology. The name “grisea ” is derived from the Latin griseus, meaning “grey,” and refers to the coloration of this species.

Distribution. Southeastern New Guinea ( Fig. 330 ). The species range as presently known occupies the Cloudy Mountains area of freshwater endemism (Area 34) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia grisea is a typical member of the R. caesius group, with flattened, ovate females, and smaller, more elongate males. It may be distinguished from other members of this group in the EPCT by the form of the male fore trochanter, which bears a dense tuft of short black setae ventrally at the apex; the weakly and broadly bowed male fore tibia ( Fig. 316 ); and the structure of the female metanotum and abdominal tergite I, which bears a pair (1+1) of depressions to either side of a broadly tumescent longitudinal midline ( Fig. 317 ).

Ecological notes. The Watuti River type-locality at Mila (CL 7166), lying in the Sagarai River basin between the Cloudy Mountains and the Pini Range, was a broad, clear, moderately swift river spreading in a fairly shallow flow 0.3–0.6 m deep over an unshaded bed of sand, gravel and cobbles, with a few faster chutes just downstream of the road ford. Rhagovelia grisea was abundant here, forming schools in the lee of large, widely scattered, emergent rocks. The species was also common at the Gumini River north of the Pini Range near Alotau, a moderately broad, unshaded lowland stream flowing smoothly through a bed of cobbles and sand, with alternating shallow riffles and deep pools ( Fig. 315 ). Throughout the Alotau area R. grisea is a species of open rivers, rather than the shaded, rocky hill streams favored by many other Rhagovelia species.

Figures

FIGS. 310–314. Rhagovelia grisea n. sp., structural details; specimens from New Guinea, Muguwe Creek, CL 7169. 310. Wingless male, dorsal habitus. 311. Wingless female, dorsal habitus. 312. Male right hind leg, dorsal view. 313. Male left paramere, outer lateral view. 314. Male proctiger, dorsal view.

FIG. 315. Gumini River, west of Alotau, Milne Bay Province, Papua New Guinea, CL 7174, habitat for R. grisea n. sp.

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

FIGS. 316–320. Rhagovelia caesius Lansbury, structural details; specimens from New Guinea, Aleater River, CL 7241. 316. Wingless male, dorsal habitus. 317. Wingless female, dorsal habitus. 318. Male right hind leg, dorsal view. 319. Male left paramere, outer lateral view. 320. Male proctiger, dorsal view.