Rhagovelia hirsuta Lansbury

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 : 93-97

Rhagovelia hirsuta Lansbury

( Figs. 146–151 )

Rhagovelia hirsuta Lansbury, 1993: 39 . Type-locality: Kokoda, Northern Prov., Papua New Guinea.

Material Examined. PAPUA NEW GUINEA, Oro Prov.: 1 wingless male, 1 wingless female, Kokoda, Mambare River, Mambe Estate , 12 September 1988, sheltered pools at side of river, R. N. B. Prior (paratypes, OXUM) .

Morobe Prov.: 17 winged males, 2 winged females, 28 wingless males, 12 wingless females, 2 immatures, Lower Aleater [Alewiri] River, nr. Kamiali , 5 m., 7°19'15"S, 147°07'35"E, 27 °C., 3 May 2003, 13:00–15:00 hrs., CL 7241, D. A. Polhemus ( USNM); 1 wingless female, “Kerosine Creek” and rocky trib., middle Aleater [Alewiri] River basin, W. of Lababia village , 30 m., 7°18'46"S, 147°06'30"E, water temp. 25 °C., 5 May 2003, 10:30–12:30 hrs., CL 7245, D. A. Polhemus ( USNM) .

Redescription.

Wingless male: Size: Length = 3.55–3.80 mm (x = 3.65, n = 5); width = 1.30–1.40 mm (x = 1.32, n = 5). Wingless female, length = 3.80–3.90 mm (x = 3.84, n = 5); width = 1.40–1.55 mm, (x = 1.45, n = 5). Winged male, length = 3.70– 3.90 mm (x = 3.83, n = 3); width = 1.50–1.60 mm (x = 1.55, n = 3). Winged female, length = 4.00– 4.10 mm (x = 4.05, n = 2); width = 1.60 mm (x = 1.60, n = 2).

Color: Dorsal ground color black, marked with pale yellow on basal antennae and anterior pronotum. Head black, juga brown, rostrum dark brown ventromedially, piceous distally; eyes dark red ( Fig. 146 ). Pronotum black, with a transversely ovate pale yellow spot anteromedially behind vertex, this yellowish coloration bounded by pruinose grey laterally, not extending downward onto the propleurae. Mesonotum, metanotum, all abdominal tergites and connexiva black; abdominal tergites uniformly dull, lacking glabrous areas. Antennal segment I with basal one-third pale yellowish-white, distal two-thirds plus all of segments II–IV black. Legs generally black, with coxae, fore and hind trochanters, basal one-fifth of fore femur dark yellow. Venter black, ventral margins of acetabula embrowned, abdominal ventrites VIII–X dark brown.

Structural characters: head moderately short, declivant anteriorly, with weakly impressed median line; length 0.35, width 0.80; length of eye along inner margin 0.30, anterior/posterior interocular space, 0.20/0.50. Pronotum short, length along midline 0.30, less than dorsal length of head, leaving mesonotum broadly exposed, width 1.05; mesonotum smooth, lacking deep foveae, length 0.75, humeri slightly depressed. Metanotum barely exposed, length 0.10. Lengths of tergites I–VIII, respectively: 0.20: 0.25: 0.20: 0.20: 0.20: 0.22: 0.40: 0.45. Connexiva with margins of even width throughout, very weakly sinuate, convergent posteriorly, posterolateral angles not modified, separated by entire width of tergite VIII, bearing a few long dark setae.

Entire dorsum thickly covered with fine, appressed pale pubescence, intermixed with numerous longer, semi-erect black setae except on central pronotum and mesonotum; legs and antennae thickly clothed with short appressed golden setae, with scattered long, erect, bristly black setae on anterodorsal faces of antennal segments I and II, and anterior margins of all femora, plus long pilose brown setae along posterior margin of hind femur, length of these latter setae equal to three-fourths the maximum thickness of the hind femur; 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 slightly flattened ventrally on distal one-third, with small concavity near apex adjacent to grasping comb; hind trochanter bearing 5–6 small dark pegs ventrally; hind femur highly incrassate, bearing two rows of teeth and pegs lying in area covered by infolded hind tibia, ventral row consisting of approximately 8 small, similarly sized black pegs running from base of femur to one-third distance from base, followed by a moderate sized dark yellow tooth with a black apex, then 2 medium-sized dark yellow teeth with black apices, then 8–10 much smaller dark brown teeth of subequal size running to apex of femur, dorsal row consisting of a 3 moderately large dark yellow teeth with a black apices arising near middle of femur, followed 4–5 smaller dark brown teeth of progressively declining size; hind tibia broadly and gently sinuate, inner surface bearing a row of about 16 small black teeth, plus one large, conical, acute, brown spine with a black apex approximately three-fourths distance from base ( Fig. 148, 149 ).

Venter of head and and adjacent inner prosternum bearing small black denticles on and around jugum; mesosternum slightly depressed centrally, margins of this depression bearing long, fine pale setae; metasternum slightly tumid, with fine, erect pale setae laterally; abdominal venter set with short appressed pale setae intermixed with longer, fine, semi-erect pale setae laterally; 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 VII broadly flattened centrally, posterior margin straight, central section quadrate, flattened, bordered to either side by patches of very short, thick, dense black setae, ventrite VIII constricted basally, lacking a pronounced longitudinal medial carina.

Male paramere shape elongate, basal section ventrally produced into a broad, rounded lobe bearing stout setae, distal section expanded apically to form a broadly curving flange ( Fig. 150 ). Male proctiger with basolateral lobes well-developed, apices angular; distolateral lobes not produced; distal cone dome-shaped, apex slightly produced, acute ( Fig. 151 ).

Lengths of antennal segments I–IV: 0.75: 0.50: 0.65: 0.55.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.00: 1.10: 0.02: 0.02: 0.30; of middle leg, 1.75: 1.30: 0.05: 0.60: 0.80; of hind leg, 1.70: 1.70: 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 thoracic and abdominal dorsum except in propleural region and sparsely on abdominal tergite I; abdomen with connexival margins straight and of even width throughout, converging relatively evenly to posterior apex of abdomen with slight inflection adjacent to suture between tergites IV and V, tufts of erect black setae present adjacent to abdominal tergite VI ( Fig. 147 ); posterolateral connexival angles forming right angles when viewed laterally, bearing thick tufts of posteriorly-directed, stiff, gently curving black setae; abdominal tergite I transversely swollen, bearing short gold setae centrally intermixed with a few longer black setae; abdominal tergites II and III angled slightly upward in anterior direction to accommodate swollen tergite I; abdominal tergites IV–VI horizontal, bearing a faintly indicated longitudinal median carina set with scattered short black setae; posterior portion of abdominal tergite VII and basal section of tergite VIII covered by convergent posterolateral angles of connexiva; proctiger angled downward at ~45°; hind trochanter lacking small black pegs; hind femora only weakly incrassate, ventral midline in area covered by infolded hind tibia bearing a single spine row consisting of a moderately long, slender, sharp, spine arising at about two-thirds distance to apex, followed by 2 smaller spines of progressively decreasing size to apex; hind tibiae straight, inner surface lacking teeth or spines; ventral coloration predominantly dark pruinose grey, lower propleural region with numerous tiny black denticles adjacent to rostrum; all abdominal ventrites lying in similar horizontal plane, abdominal sternite I incipiently carinate medially, with a small, posteriorly-directed triangular process centrally; gonocoxal commissure carinate.

Winged male: Similar to wingless male in general structure and coloration, but with following exceptions: pronotum greatly enlarged, completely covering meso- and metanotum, width 1.55, length 1.50; humeri prominent, anterior lobe with obscure transverse dark yellow patch centrally, overlain with silvery pruinosity, areas lateral to this patch silvery pruinose, remainder of pronotum black, posterior pronotal lobe angular, central portion domed, posterior portion set with numerous tiny foveae, entire pronotum covered with short recumbent gold setae, propleurae and posterior margin bearing scattered long, erect black setae; abdomen not reflexed, lying in a uniformly horizontal plane when viewed laterally; forewings uniformly dark blackish-brown, 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 apterous male.

Winged female: Similar to wingless male in general body form and coloration, with following exceptions: body size slightly larger, pronotum width 1.60, length 1.45.

Distribution. Southeastern New Guinea; from the Kokoda area northeastward through the Bowutu Mountains ( Fig. 153 ). The species range as presently known occupies the Morobe Highands area of freshwater endemism (Area 22) as delineated by D. Polhemus & Allen (2007).

Discussion. Lansbury (1993) combined under the concept of this species multiple populations from Oro, Central and Eastern Highlands provinces in Papua New Guinea, occupying drainage basins both north and south of the island’s central divide. Although not all of these specimens have been examined, it is likely that these various populations may eventually prove to represent separate species.As far as can be determined here, R. hirsuta occurs only in drainage basins on the northern side of the Papuan Peninsula from the Kokoda area northeastward to Kamiali.

The author has examined wingless male and female paratypes from the type-locality at Kokoda, held in the Oxford University Museum. They conform to the re-description presented above, which is based on more recently collected specimens from Kamiali. The female of R. hirsuta can be distinguished from R. peggiae by the setiferation of the connexiva and the abdominal tergites (compare Figs. 141 , 147 ), as discussed under that species. Males of the two species may be easily separated by the shape of the paramere and proctiger (compare Figs. 143, 144 to Figs. 150, 151 ).

The morphology of male abdominal ventrite VII is similar in both species, being quadrately flattened centrally, with this area bordered laterally by a pair (1+1) of raised ridges bearing dense patches of very short black setae. This similarity may have confused Lansbury and caused him to include specimens of R. peggiae from Mafulu, in the Auga River basin, under this species concept. It is suspected that his Mafulu paratype specimens may instead represent R. peggiae , which Lansbury knew only from the brief description presented by Kirkaldy (1901), since a series of R. peggiae , confirmed by examination of the male paramere shape, was taken by the author at the Mas River, only 4 km east of Mafulu. It is not clear which species is represented in his records of paratypes from the Eastern Highlands Province, but it is suspected that these also represent a different species.

Ecological notes. A long series of R. hirsuta was taken along the margins of the terminal reach of the Aleater River, near Kamiali village. The river here was broad and clear, flowing smoothly over a bed of cobbles, gravel and sand, with some runs in the central channel up to 2 m deep, and bordered by broad areas of shallower water ( Fig. 152 ). The channel was almost entirely unshaded, with the margins consisting of broad cobble and sand bars. In the midreach section further upstream the river occupied a deep trench carved into alluvial valley fill, with vertical walls up to 10 m high of consolidated gravel and cobbles. It appeared that the river had carved its way downward into alluvium carried into its valley by landslides from the rather unstable ophiolite terrain that enclosed the drainage basin. The collection of R. hirsuta at this site occurred after several days of heavy rain, and likely consisted of individuals that had been washed down to the river mouth from further upstream, since the debris stranding line indicated that the river's water level had been at least 1 m higher over previous days. As such, this record from near sea level at Kamiali should be considered potentially anomalous, since based on other material examined this seems to be a species more typical of shaded, middle elevation streams.

Figures

FIGS. 146–151. Rhagovelia hirsuta Lansbury, structural details; specimens from New Guinea, Morobe Prov., Kamiali, CL 7241. 146. Wingless male, dorsal habitus. 147. Wingless female, dorsal habitus. 148. Male right hind leg, posterior view. 149. Male right hind leg, dorsal view. 150. Male left paramere, outer lateral view. 151. Male proctiger, dorsal view.

FIG. 153. Distributions of species in the R. auga and R. peggiae subgroups 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.

FIG. 152. Lower Aleater River, near Kamiali, Morobe Province, Papua New Guinea, CL 7241, habitat for R. caesius Lansbury and R. hirsuta Lansbury.