Rhagovelia torrenticola, 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 : 79-82

Rhagovelia torrenticola new species

( Figs. 125–132 )

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Milne Bay Prov., D'Entrecasteaux Islands, Goodenough Island, Tuabeda River at Kalauna village , 335 m., 9°23'01"S, 150°19'32"E, water temp. 22.5° C., 26 August 2002, 10:00–12:00 hrs., CL 7184, D. A. & J. T. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Milne Bay Prov., D'Entrecasteaux Islands, Goodenough Island : 1 winged female, 4 wingless males, 1 wingless female, same data as holotype, CL 7184, D. A. & J. T. Polhemus ( USNM, BPBM) ; 3 wingless males, 1 wingless female, Kuliana Creek at Ewaoiana, near Kalauna village , 290 m., 9°22'54"S, 150°19'30"E, water temp. 24.5° C., 26 August 2002, 10:00–12:00 hrs., CL 7185, D. A. & J. T. Polhemus ( USNM, BPBM) ; 1 wingless male, Yalaauau River , NW of Kalauna village, 320 m., 9°22'51"S, 150°19'22"E, water temp. 22.5° C., 26 August 2002, 12:30–13:15 hrs., CL 7186, D. A. & J. T. Polhemus ( BPBM) .

Description.

Wingless male: Size: Length = 4.00– 4.30 mm (x = 4.10, n = 5); width = 1.35–1.60 mm (x = 1.47, n = 5). Wingless female, length = 4.05–4.20 mm (x = 4.12, n = 2); width = 1.55–1.60 mm, (x = 1.57, n = 2). Winged female, length = 4.35 mm (n = 1); width = 1.60 mm (n = 1).

Color: Dorsal ground color dull black, marked with pale yellow on anterior pronotum and outer connexiva, dark yellow on basal antennae and legs ( Fig. 125 ). Head dull back, tylus brown, jugae dark yellow; rostrum pale yellowish-brown, fuscous medially, piceous distally; eyes dark red. Pronotum dull black, overlain with silvery pruinose laterally, transversely rectangular pale yellow patch present anteriorly behind head vertex, this pale anterior coloration not extending laterally onto propleurae. Mesonotum, metanotum and all abdominal tergites dull black except posteromedial portion of tergite VII and all of tergite VIII slightly shining, connexiva dull black on inner halves, pale yellow on outer halves. Antennal segment I with basal one-third pale yellow, distal half plus all of segments II–IV black. Legs generally black, with coxae, trochanters, basal half of fore femur dorsally and ventrally, basal one-fifth of hind femur dorsally dark yellow, entire ventral surface of hind femur pale brown. Venter dull dark grey, with ventral sections of propelurae and all acetabula pale yellow, abdominal ventrites VII and VIII brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.41, width 0.98; length of eye along inner margin 0.35, anterior/posterior interocular space, 0.20/0.55. Pronotum short, width 1.30, length along midline 0.30, shorter than dorsal length of head, leaving mesonotum broadly exposed; mesonotum smooth, tumescent, lacking foveae, with a weakly raised longitudinal midline, length at midline 0.85; metanotum moderately exposed, roughly crescent-shaped, length at midline 0.10. Lengths of abdominal tergites I–VIII, respectively: 0.25: 0.30: 0.25: 0.25: 0.25: 0.25: 0.50: 0.45. Connexiva with margins of even width throughout, margins very weakly sinuate, 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 numerous long, erect black setae, these black setae absent on central section of mesonotum; legs and antennae thickly clothed with short appressed gold setae, with scattered long, erect, bristly black setae on anterodorsal faces of antennal segments I and II, anterior margins of all femora; fore and middle trochanters lacking pegs or teeth, hind trochanter bearing 12 small black denticles ventrally; fore femur with ventral margin bearing a thick fringe of pale, semi-erect, moderately long setae plus a comb of 7–8 long, slender, erect, evenly spaced black setae; fore tibia with anterior margin bearing numerous semi-erect, pale, moderately long setae intermixed with long, slender, erect black setae, slightly widened distally, ventral surface flattened, forming a concave channel adjacent and parallel to grasping comb; middle femur simple, slightly tapering distally, bearing scattered long, slender, erect black setae along posterior margin; hind femur highly incrassate, with scattered very long, slender, pilose brown setae posterodorsally, posterior margin bearing two parallel rows of teeth, ventral row lying in area covered by infolded hind tibia and consisting of 15 small, dot-like teeth basally, followed by a moderate sized spine, followed by 18 additional small, subequally sized black teeth distally, dorsal row of teeth commencing at middle of femur with a stout, acute orange-brown spine with a black apex, followed by broad gap distally, then by 5 smaller black teeth of progressively declining size toward femoral apex, all orange-brown with black apices; hind tibia broadly and gently sinuate, inner surface bearing a single row of 15 small, stout, peg-like black teeth on basal two-thirds, then a large, acute black tooth, then 4 more moderate sized stout black teeth distally ( Figs. 127, 128 ).

Venter of head and thorax with black denticles only at the extreme anterior margins of the propleura adjacent to antennal tubercles and jugum; mesosternum slightly depressed centrally, margins of this depression and adjacent lateral metasternum bearing long, fine gold setae arranged in a V-shaped pattern with apex directed anteriorly; metasternum raised centrally, with a pair (1+1) of small, concave depressions on lateral sections; abdominal venter set with short appressed gold setae, these setae denser on abdominal tergite VII; 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 with a pair (1+1) of shallow depressions on posterior half to either side of longitudinal midline, ventrite VIII strongly depressed on basal half.

Male paramere shape elongate, distal section expanded, posterior margin nearly straight, apex angled upward and broadly rounded ( Fig. 129 ). Male proctiger with basolateral lobes prominent, broadly expanded, apices rounded; distolateral lobes not developed; distal cone roughly triangular, tapering to an angular apex ( Fig. 130 ).

Lengths of antennal segments I–IV: 1.25: 0.60: 0.75: 0.70.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2 of fore leg, 1.30: 1:45: 0.04: 0.02: 0.35; of middle leg, 2.30: 1.70: 0.10: 0.70: 0.95; of hind leg, 2.30: 2.15: 0.05: 0.15: 0.35.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: long, erect black setae on dorsum largely absent except on pro- and mesopleurae, posterior margins of mesonotum, metanotum, and abdominal tergite I, and very sparingly on posteromedial margins of abdominal tergites II and III; connexiva open and angled outward from abdominal tergites, connexival margins straight, narrow, unmodified, converging evenly to posterior apex of abdomen, posterior apices separated by full width of abdominal tergite VII ( Fig. 126 ), posterolateral apices forming approximately 100° angles, bearing a few short, posteriorly-directed black setae; abdominal tergites II–V dull and nearly hair-free, with narrow patches of slightly raised, very short gold setae along longitudinal midlines, tergites VI–VII with small, longtitudinally elongate, shining black patches centrally, tergite VIII entirely shining black; abdominal tergites IV-VII lacking long, erect black setae; abdominal tergite VIII lying in horizontal orientation, proctiger angled downward at 45° from horizontal; hind femur only weakly incrassate, bearing a single row of teeth below infolded tibia, beginning with a small, sharp black tooth near midpoint, followed by 3 more very small black teeth distally; hind tibia straight, inner surface lacking teeth; ventral coloration predominantly dark grey, with ventral section of propleura, prosternum, and all acetabula dark yellow, abdominal ventrites V–VIII and gonocoxae brown; gonocoxae raised at commissure along ventral midline, forming a small, acute carina.

Winged female: Similar to wingless female in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.60, length 1.50, 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 dark blackish-brown, broadly domed, posterior half with small, obscure foveae, posterior margin broadly angular, bearing scattered long, gently curving, semi-erect black setae; forewings dark blackish-brown, becoming slightly paler brown basally, veins darker, 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.

Winged male: Unknown.

Etymology. The name “torrenticola ” is derived from the Latin torrens, referring to a swift stream, and cola, Latin for “dweller,” and refers to the preference of this species for swift mountain streams on Goodenough Island.

Distribution. D’Entrecasteaux Islands; endemic to Goodenough Island ( Fig. 132 ). The species range as presently known falls within the D’Entrecasteaux Islands area of freshwater endemism (Area 35) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia torrenticola is a large, robust species occurring on swift, rocky streams in the uplands of Goodenough Island. The male paramere is similar to that of R. awaetowa from nearby Fergusson Island (compare Figs. 122 , 129 ), but the central section is broader, and the distal section possesses an area of thinned integument centrally that creates a pale yellow “window” ( Fig. 129 ), which is not present in R. awaetowa . The shape of the male proctiger is also distinctively different, with laterally expanded basolateral lobes far larger and more laterally expanded in R. torrenticola (compare Figs. 123 , 130 ). Rhagovelia torrenticola is also similar to R. dibuwa from Normanby Island in exhibiting intraspecific color polymorphism, with both dark and orange-brown morphs present. Such color polymorphism has not yet been observed in R. awaetowa or R. kalawai , the other two insular endemics in the R. dibuwa subgroup. For additional comparisons of this species to others in this subgroup see the discussions under R. awaetowa and R. dibuwa .

Ecological notes. Rhagovelia torrenticola is an upland species, being found in the swift rivers of Goodenough Island above 300 m elevation. The Tuabeda River at the type-locality (CL 7184) was a cold, clear, high volume stream crashing down through a steeply-dropping, nearly unshaded bed of granitic boulders ( Fig. 131 ). Rhagovelia torrenticola was uncommon here, being found only on the shallow outflows from a small spring on the channel margin.A few additional specimens were taken at Kuliana Creek (CL 7185) and the Yalaauau River (CL 7186), both of these being high gradient streamlets flowing amid beds of boulders. All of these sites were near villages, in areas where the forest had been cleared, leaving the stream channels open to full sunlight.

Figures

FIGS. 125–130. Rhagovelia torrenticola n. sp., structural details; specimens from Goodenough Island. 125. Wingless male, dorsal habitus, specimen from Yalaauau, CL 7186. 126. Wingless female, dorsal habitus, specimen from Tuabeda River at Kalauna, CL 7184. 127. Male right hind leg, posterior view. 128. Male right hind leg, dorsal view; 127 and 128 from Yalaauau, CL 7186. 129. Male left paramere, outer lateral view. 130. Male proctiger, dorsal view; 129 and 130 from Tuabeda River at Kalauna, CL 7184.

FIG. 131. Tuabeda River above Kalauna village, Goodenough Is., Milne Bay Province, Papua New Guinea, CL 7184, typelocality for R. torrenticola n. sp.

FIG. 132. Distributions of species in the R. dibuwa subgroup in eastern New Guinea and adjacent islands.

FIGS. 118–123. Rhagovelia awaetowa n. sp., structural details; specimens from Fergusson Island. 118. Wingless male, dorsal habitus. 119. Wingless female, dorsal habitus. 120. Male right hind leg, posterior view. 121. Male right hind leg, dorsal view; 118–121 from upper Awaetowa River, CL 7225. 122. Male left paramere, outer lateral view. 123. Male proctiger, dorsal view; 122 and 123 from lower Awaetowa River, CL 7183.