Rhagovelia sapoi, 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 : 116-119

Rhagovelia sapoi n. sp.

( Figs. 32 , 34, 188–193, 201)

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Gulf Prov., New Guinea, Sapoi River and rocky tributary upstream of Ivimka Research Station , 120–150 m., 7°43'36"S, 146°29'59"E, water temp. 27° C. (river), 24.5° C. (rocky trib.), 16 January 2001, 07:00–13:00 hrs., from rocky trib., CL 7148c, D. A. Polhemus ( USNM) . Paratypes: PAPUA NEW GUINEA, Gulf Prov., New Guinea: 3 wingless males, 4 wingless females, same data as holotype, 7148c, D. A. Polhemus ( USNM, BPBM) ; 1 wingless male, New Guinea, same data as preceding except from margins of pools on main Sapoi River channel, next to logs and vertical banks, CL 7148b, D. A. Polhemus ( USNM) ; 1 wingless female, same data as preceding except from small rocky hill streamlet entering rocky trib. to Sapoi River , CL 7148d, D. A. Polhemus ( USNM) .

Description

Wingless male: Size: Length = 4.10– 4.60 mm (x = 4.43, n = 5); width = 1.40–1.60 mm (x = 1.51, n = 5). Wingless female, length = 4.10–4.70 mm (x = 4.42, n = 5); width = 1.40–1.90 mm, (x = 1.62, n = 5).

Color: Dorsal ground color black, marked with dark yellow on basal antennae, anterior pronotum, connexiva and legs ( Fig. 188 ). Head black, juga and rostrum dark yellow, rostrum fuscous ventromedially, piceous distally; eyes silver. Pronotum dark yellow on anterior half, this yellowish coloration continuing laterally as a continuous band onto the propleurae, posterior half black. Mesonotum, metanotum and abdominal tergites I–VI black, posteromedial section of abdominal tergite VII and all of tergites VIII and IX dark brown; all abdominal tergites uniformly dull and lacking glabrous areas, tergite VII slightly shining posteromedially; connexiva dark blackish-brown on inner halves, dark yellow on outer halves, ventral faces also dark yellow. Antennal segment I with basal one-third dark yellow, distal two-thirds plus all of segments II–IV black. Legs generally black dorsally, with coxae, trochanters, basal half of fore femur, and hind femur ventrally yellowish-white. Venter dark brown, with all acetabula and prosternum yellowish-white, abdominal ventrites VII–IX orange-brown.

Structural characters: Head moderately short, declivant anteriorly, with weakly impressed median line; length 0.35, width 0.85; length of eye along inner margin 0.40, anterior/posterior interocular space, 0.20/0.40. Pronotum short, length along midline 0.25, less than dorsal length of head, leaving mesonotum broadly exposed, width 1.05; mesonotum smooth, lacking deep foveae, humeri depressed, length 0.65. Metanotum barely exposed, length 0.10. Lengths of tergites I–VIII, respectively: 0.20: 0.25: 0.20: 0.20: 0.20: 0.25: 0.45: 0.50. Connexiva with margins of even width throughout, 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; 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, plus long pilose brown setae along posterior margins of all femora, particularly dense on hind femur, length of these setae equal to the thickness of the respective femora on which they occur; 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-fourth, longitudinally channeled adjacent to grasping comb; hind trochanter bearing 16–18 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 10 tiny, closely appressed black pegs running from base of femur to one-third distance from base, followed by a moderate sized dark yellow spine with a black apex, then 12–14 smaller spines with black apices running to apex of femur, dorsal row consisting of a single large yellow spine with a black apex dorsally offset near midpoint from main grouping, followed by another large spine with a black apex at two thirds distance to apex followed by 5–6 teeth of progressively declining size, all these teeth orange-brown basally with black apices; hind tibia broadly and gently sinuate, inner surface bearing a row of about 18 small dark teeth, plus one large, acute, orange-brown spine with a black apex approximately two-thirds distance from base ( Figs. 190, 191 ).

Venter of head and thorax bearing numerous small black denticles on jugum and adjacent inner prosternum ( Fig. 32 ), a few of these denticles extending upward onto propleural region; mesosternum slightly depressed centrally, margins of this depression bearing long, fine gold setae; metasternum tumid, with fine, erect pale setae laterally; abdominal venter set with short appressed pale setae intermixed with longer, fine, semi-erect pale setae laterally and along longitudinal midline; 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, this carina continuing in less pronounced form onto ventrites III–V; ventrite VI unmodified, ventrite VII broadly concave centrally, ventrite VIII constricted basally.

Male paramere shape elongate, slender, basal section slightly expanded, ventrally angular, bearing numerous stout golden setae, distal section paddle-like, apex truncate ( Fig. 192 ). Male proctiger with basolateral lobes well developed, angular, anterior margins straight, orthogonal to longitudinal midline; distolateral lobes not developed; distal cone broadly triangular, apex slightly angular ( Fig. 193 ).

Lengths of antennal segments I–IV: 0.90: 0.50: 0.62: 0.60.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 1.10: 1.15: 0.02: 0.02: 0.30; of middle leg, 1.85: 1.35: 0.05: 0.55: 0.85; of hind leg, 1.85: 1.85: 0.05: 0.15: 0.27.

Wingless female: Similar to wingless male in general structure and coloration, with following exceptions: pronotum predominantly dark yellow to orange-brown, with only extreme posterior margin black; mesonotum dark reddish brown; metanotum and abdominal tergites I–VIII predominantly black, weakly dark reddish brown along longitudinal midline, posterior section of abdominal tergite VIII and all of tergite IX orange-brown; long, semi-erect dark setae absent on thoracic and abdominal dorsum except in propleural region; connexival margins straight and of even width throughout, converging evenly to posterior apex of abdomen ( Fig. 189 ), posterolateral angles forming right angles when viewed laterally, bearing short, angular tufts of posteriorly-directed stiff black setae; abdominal tergite VIII and proctiger angled downward at 45°; hind trochanter bearing 4 small black pegs; hind femora only weakly incrassate, area covered by infolded hind tibia bearing a single spine row consisting of 4 small black pegs basally, then 5 small, sharp, orange-brown spines with black tips, then a single large orange-brown spine with a black tip, then a double row of small black pegs with 8 pegs ventrally and 4 pegs dorsally; hind tibiae straight, inner surface lacking teeth; ventral coloration predominantly orange-brown, with metasternum black; venter with prosternum bearing tiny black denticles, these less extensive than in male; all abdominal ventrites lying in similar horizontal plane, ventrite VII medially notched on posterior margin to accommodate keel-like commisure of gonocoxae (Fig. 34).

Winged male: Unknown.

Winged female: Unknown.

Etymology. The name “sapoi ” is a noun in apposition, and refers to the Sapoi River type-locality.

Distribution. Southeastern New Guinea; currently known only from the Lakekamu River basin ( Fig. 201 ). The species range as presently understood occupies the Papuan Gulf Foreland area of freshwater endemism (Area 25) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia sapoi is a relatively large, robust species currently known from the Lakekamu River basin of the southern Papua New Guinea. In general body form it is similar in some respects to R. mimani from the Kemp Welch River system to the east, with the females having straight, evenly convergent connexival margins, but the males of R. sapoi are more robust and have their connexival margins weakly sinuate (compare Figs. 188 , 194 ). The male hind leg has three spines much larger than the others, arranged in a triangular pattern when viewed ventrally ( Figs. 191, 192 ).

The two species are easily separated by the presence of black denticles on the prosternum and proacetabula of R. sapoi ( Fig. 32 ), which are lacking in R. mimani , and by the shape of the male paramere, which is apically truncate in both species, but with the distal arm straight-sided in R. mimani , versus angled vertically upward in a shape reminiscent of a hockey stick in R. sapoi (compare Figs. 192 , 198 ). The male proctiger morphology is also very different in the two species, with R. mimani having raised, anteriorly convergent ridges adjacent to the central membranous basal section, which are absent in R. sapoi (compare Figs. 193 , 199 ). The form of male abdominal ventrite VII also differs between the two species, with R. sapoi having raised setiferous ridges laterally flanking a central sulcus, with both the ridges and sulcus being absent in R. mimani . Finally, in females of R. sapoi the posterior margin of abdominal ventrite VII bears a deep, narrow, longitudinal notch to accommodate the raised, carinate commissure of the gonocoxae, with this notch flanked to either side by small, reddish-brown glabrous lips (Fig. 34); such a notch on ventrite VII is absent in R. mimani .

Ecological notes. The type-locality was a secondary tributary to the Sapoi River, upstream of the Lakekamu research station. This tributary was a swift, rocky, high gradient stream, which entered the main Sapoi River at the downstream end of a long pool along the river channel. The gradient of the tributary moderated as one progressed upstream, with small, stair-stepping streamlets entering it from the hilly banks on either side. The author’s field notes indicate: “A very pretty orange and black Rhagovelia was taken on a streamlet feeding the tributary, a classic stair-step profile with small cascades and shallow pools, well shaded.” A preference for such first order stream habitats is typical for many species in the R. novacaledonica group.

Figures

FIG. 32. Rhagovelia sapoi n. sp., ventral view of head and prosternum showing presence and distribution of black denticles; specimen from New Guinea, Sapoi River, CL 7148. FIGS. 33, 34. Rhagovelia species, comparative ventral views of female terminal abdomen. 33. R. mimani n. sp., specimen from New Guinea, Dorobisoro, CL 7261. 34. R. sapoi n. sp., specimen from New Guinea, Sapoi River, CL 7148.

FIGS. 188–193. Rhagovelia sapoi n. sp., structural details; specimens from New Guinea, Sapoi River tributary, CL 7148. 188. Wingless male, dorsal habitus. 189. Wingless female, dorsal habitus. 190. Male right hind leg, posterior view. 191. Male right hind leg, dorsal view. 192. Male left paramere, outer lateral view. 193. Male proctiger, dorsal view.

FIG. 201. Distributions in eastern New Guinea of species held as Incertae Sedis within the R. novacaledonica group in regard to subgroup assignments.

FIGS. 194–199. Rhagovelia mimani n. sp., structural details; specimensfrom New Guinea, Mimani River basin, nearDorobisoro. 194. Wingless male, dorsal habitus; specimen from Mimani River tributary, CL 7262. 195. Wingless female, dorsal habitus. 196. Male right hind leg, posterior view. 197. Male right hind leg, dorsal view; 195–197 from Mimani River tributary, CL 7263. 198. Male left paramere, outer lateral view. 199. Male proctiger, dorsal view; 198 and 199 from Mimani River tributary, CL 7259.