Rhagovelia awaetowa, 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 : 74-79

Rhagovelia awaetowa new species

( Figs. 24 , 30 , 118–124 , 132 )

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Milne Bay Prov., D'Entrecasteaux Islands, Fergusson Island, east coast, upper Awaetowa [Basuenoia] River and rocky tribs., W. of Basima , 575–650 m., water temp. 22° C., 27 January 2003, 10:00–14:00 hrs., 9°30'34"S, 150°48'17"E, first tributary, CL 7225b, D. A. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Milne Bay Prov., D'Entrecasteaux Islands, Fergusson Island : 21 wingless males, 34 wingless females, 3 immatures, same data as holotype, CL 7225b, D. A. Polhemus ( USNM, BPBM) ; 1 winged male, 11 wingless males, 13 wingless females, east coast, upper Awaetowa River and rocky tribs., W. of Basima , 575– 650 m., water temp. 22° C., 27 January 2003, 10:00–14:00 hrs., 9°30'34"S, 150°48'17"E, along margins of main channel, CL 7225a, D. A. Polhemus ( USNM, BPBM) ; 4 winged males, 6 winged females, 49 wingless males, 43 wingless females, 2 immatures, east coast, Awaetowa River, midreach, E. of Basima , 45 m., 9°27'41"S, 150°49'38"E, water temp. 27° C., 26 January 2003, 13:00–16:30 hrs., CL 7183a, D. A. Polhemus ( USNM, BPBM) ; 6 wingless males, 5 wingless females, east coast, Awaetowa River, lower midreach, E. of Basima , 15 m., 9°27'34"S, 150°49'37"E, water temp. 23° C., 25 August 2002, 09:45–11:15 hrs., CL 7183b, D. A. & J. T. Polhemus ( USNM) ; 1 winged female, 1 wingless male, east coast, Mebulibuli Creek and rocky tributary, 1.3 km. upstream of mouth, S. of Basima , 15– 75 m., 9°30'54"S, 150°52'04"E, water temp. 24° C., 24 August 2002, 09:00–13:00 hrs., CL 7180b, rocky tributary, D. A. & J. T. Polhemus ( USNM) .

Description.

Wingless male: Size: Length = 4.30–4.80 mm (x = 4.48, n = 5); width = 1.30–1.70 mm (x = 1.50, n = 5). Wingless female, length = 4.10–4.50 mm (x = 4.30, n = 5); width = 1.40–1.60 mm, (x = 1.54, n = 5). Winged male, length = 4.60 mm (n = 1); width = 1.70 mm (n = 1). Winged female, length = 4.20–4.30 mm (x = 4.25, n = 2); width = 1.60 mm (x = 1.60, n = 2).

Color: Dorsal ground color dark grey, marked with orange on anterior pronotum and outer connexiva, dark yellow on basal antennae and legs ( Fig. 118 ). Head dark grey; rostrum pale yellowish-brown, fuscous medially, piceous distally; eyes dark red. Pronotum dark grey, with transverse yellowish-orange patch anteriorly behind head vertex, this pale anterior coloration not extending laterally onto propleurae. Mesonotum, metanotum and abdominal tergites dark grey, all tergites uniformly dull and lacking shining areas except for tergite VII slightly shining, connexiva dark grey on inner halves, pale orange 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, basal 1/5 of hind femur dorsally, basal sections of fore and hind femora ventrally, extreme base of middle femur ventrally dark orange-yellow. Venter dark grey, with ventral sections of propelurae, prosternum, pro- and mesoacetabulae, central sections of abdominal ventrites V–X dark orange.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.50, width 1.00; length of eye along inner margin 0.40, anterior/posterior interocular space, 0.25/0.55. Pronotum short, width 1.30, length along midline 0.40, shorter than dorsal length of head, leaving mesonotum broadly exposed; mesonotum smooth, tumescent, lacking foveae, with a weakly raised longitudinal midline, length at midline 0.95; metanotum moderately exposed, roughly crescent-shaped, length at midline 0.10. Lengths of abdominal tergites I–VIII, respectively: 0.25: 0.35: 0.25: 0.30: 0.30: 0.35: 0.55: 0.50. Connexiva with margins of even width throughout, margins nearly straight and evenly convergent posteriorly, posterolateral angles not modified, bearing only small tufts of short setae ( Fig. 24 ), separated by entire width of tergite VIII.

Entire dorsum and laterotergites covered with fine, appressed pale pubescence, intermixed with scattered 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 10 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 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 6 small, subequal sized black teeth basally, followed by a moderate sized spine, followed by 8 additional subequal sized black teeth distally, dorsal row of teeth commencing on distal third of femur with a large, acute orange-brown spine with a black apex, followed by 5 smaller black teeth of progressively declining size toward femoral apex, all teeth orange-brown with black apices; hind tibia broadly and gently sinuate, inner surface bearing a single row of 10 small black teeth on basal half, then a large, acute tooth, then 2 more moderate sized teeth, then a gap to three moderate sized teeth at tibial apex, these latter 6 teeth all orange-brown with black apices ( Figs. 120–121 ).

Venter of head and thorax lacking black denticles; meso- and metasterna 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; 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 weakly angular centrally ( Fig. 30 ).

Male paramere shape elongate, with scattered short, stiff setae present centrally along ventral margin, distal portion expanded, apex angled upward, broadly rounded ( Fig. 122 ). Male proctiger with basolateral lobes prominent, angular; distolateral lobes not developed; apical cone tapering evenly to an angular apex ( Fig. 123 ).

Lengths of antennal segments I–IV: 1.25: 0.70: 0.90: 0.75.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2 of fore leg, 1.65: 1:65: 0.05: 0.02: 0.30; of middle leg, 2.50: 1.75: 0.10: 0.75: 1.00; of hind leg, 2.50: 2.30: 0.05: 0.20: 0.50.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: connexival margins straight, unmodified, converging evenly to posterior apex of abdomen, apices separated by full width of abdominal tergite VII ( Fig. 119 ), posterolateral angles slightly rounded, bearing small, posteriorly-directed, angular tufts of black setae; abdominal tergites II–V with narrow patches of slightly raised, moderate length pale setae along longitudinal midlines, tergites VI–VII with small, longtitudinally elongate, shining black patches centrally; 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 4 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 III–VIII and gonocoxae brown.

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.70, length 1.60, 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 uniformly dark blackish-brown, 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. Hind femur less incrassate than in wingless male, with armature reduced.

Winged female: Similar to winged male in general body form and coloration, pronotum width 1.60, length 1.60.

Etymology. The name “awaetowa ” is a noun in apposition, and refers to the Awaetowa River type-locality, near Basima on Fergusson Island.

Distribution. D’Entrecasteaux Islands; endemic to Fergusson 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 awaetowa is endemic to Fergusson Island, and is the largest member of the R. dibuwa subgroup occurring in the D'Entrecasteaux Islands, with some males attaining body lengths of 4.80 mm. It is similar to R. torrenticola from adjacent Goodenough Island in having a low, rounded carinae dorsally at the base of the proctiger, and only a weakly produced medial process on the posterior margin of female abdominal ventrite VII ( Fig. 30 ), but can be separated from that species by the less expansively developed basolateral lobes on the male proctiger (compare Figs. 123 and 130 ), and the absence of a translucent patch subapically on the male paramere (see discussion under R. torrenticola ). In addition, the various samples of R. awaetowa taken on Fergusson Island at elevations ranging from 15–650 m show no indication of intraspecific color variation, displaying a uniformly dark grey ground color, with orange-brown morphs lacking, even in higher elevation samples. By contrast, R. torrenticola from Goodenough Island and R. dibuwa from Normanby Island, which lie immediately to the west and east of Fergusson respectively, both exhibit such color polymorphism.

Ecological notes. This species has been collected across a wide elevational range on Fergusson Island, from the lower reaches of the Awaetowa River near Basima to the river headwaters at 650 m, but was more abundant in the latter area. It seems likely that the species prefers higher elevation habitats, but that individuals are occasionally washed downriver during floods.The name of this river is shown as the Basuenoia on Papua New Guinea Topographic Survey map sheet 9079 (Koitabu), but over the course of several visits to Basima in 2002 and 2003 it was always referred to by the local people there as the Awaetowa.

Along the headwater reach of the Awaetowa River this species was taken from sheltered areas along the margins of this swift, rocky stream, which had a bed profile of alternating small cascades and pools up to 3 m in depth, amid very large metamorphic boulders ( Fig. 124 ). Additional specimens were taken on a smaller tributary that entered from the south bank, consisting of alternating small cascades and flowing pools, heavily shaded by moss-covered montane forest.

Figures

FIGS. 20–25. Species of the Rhagovelia dibuwa subgroup, female terminal abdomen, lateral view, showing structural variation on ventrites VII and VIII. 20. R. watuti n. sp., specimen from New Guinea, Cloudy Mtns., CL 7175; 21. R. peninsularis n. sp., specimen from New Guinea, Alotau, CL 7163; 22. R. kalawai n. sp., specimen from Sideia Is., Kwabunamoa River, CL 7287; 23. R. dibuwa n. sp., specimen from Normanby Is., Dibuwa River, CL 7230; 24. R. awaetowa n. sp., specimen from Fergusson Is., Awaetowa River, CL 7225; 25. R. torrenticola n. sp., specimen from Goodenough Is., Tuabeda River, CL 7184.

FIGS. 26–31. Species of the Rhagovelia dibuwa subgroup, female terminal abdomen, ventral view, showing structural variation on posterior margin of ventrite VII. 26. R. watuti n. sp., specimen from New Guinea, Cloudy Mtns., CL 7175; 27. R. peninsularis n. sp., specimen from New Guinea, Alotau, CL 7163; 28. R. kalawai n. sp., specimen from Sideia Is., Kwabunamoa River, CL 7287; 29. R. dibuwa n. sp., specimen from Normanby Is., Dibuwa River, CL 7230; 30. R. awaetowa n. sp., specimen from Fergusson Is., Awaetowa River, CL 7225; 31. R. torrenticola n. sp., specimen from Goodenough Is., Tuabeda River, CL 7184.

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.

FIG. 124. Awaetowa River headwaters, Fergusson Is., Milne Bay Province, Papua New Guinea, CL 7225, type-locality for R. awaetowa n. sp.

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

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.