Rhagovelia yela, 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 : 133-135

Rhagovelia yela new species

( Figs. 167 , 202 , 220–226 , 240 , 302 )

Type material examined. Holotype, wingless male: PAPUA NEW GUINEA, Milne Bay Prov., Louisiade Archipelago, Rossel [Yela] Island, Woa River and rocky tributaries, approx. 4 km. upstream from estuary, 0–150 m., 11°20'37"S, 154°07'06"E, water temp. 23 °C., 31 August–1 September 2002, CL 7196a, D. A. & J. T. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Milne Bay Prov., Louisiade Archipelago, Rossel [Yela] Island: 3 winged males, 2 winged females, 79 wingless males, 62 wingless females, same data as holotype, CL 7196a, D. A. & J. T. Polhemus ( USNM, BPBM) ; 3 winged males, 2 wingless males, 3 wingless females, rocky tributary to Woa River , approx. 4 km. upstream from estuary, 15– 30 m., 11°20'45"S, 154°07'30"E, 31 August 2002, CL 7196b, D. A. & J. T. Polhemus ( USNM) ; 1 winged female, 7 wingless males, 3 wingless females, small cascading tributary to Woa River , approx. 4 km. upstream from estuary, 30– 60 m., 11°20'54"S, 154°07'55"E, 1 September 2002, CL 7196c, D. A. Polhemus ( USNM) ; 2 winged males, 6 wingless males, 1 wingless female, Woa River and rocky tributaries, approx. 4 km. upstream from estuary, 15– 30 m., 11°20'42"S, 154°07'18"E, water temp. 23 °C., 31 August 2002, tributary with waterfall, CL 7196d, D. A. & J. T. Polhemus ( USNM) .

Description

Wingless male: Size: Length = 2.35–2.70 mm (x= 2.54, n = 5); width = 1.00– 1.15 mm (x = 1.09, n = 5). Wingless female, length = 2.10–2.20 mm (x = 2.16, n = 5); width = 1.20–1.25 mm, (x = 1.23, n = 5). Winged male, length = 2.80 mm (n = 1); width = 1.10 mm (n = 1). Winged female, length = 3.20–3.30 mm (x = 3.25, n = 2); width = 1.20–1.35 mm (x = 1.27, n = 2).

Color: Ground color black, with limited pale orange to yellowish markings on anterior pronotum, acetabula, basal legs and antennae ( Fig. 220 ). Head black; rostrum dark whitish yellow, fuscous medially, piceous distally. Pronotum black, bearing an elongate transverse pale orange patch centrally behind anterior margin, this patch narrowly bisected along longitudinal midline by a darker orange line. Mesonotum, metanotum and abdomen black, connexival margins narrowly dark brown. Antennae black, with basal one-third of segment I pale yellowish white. Legs black to dark brown, with coxae, fore and hind trochanters, basal half of fore femur, extreme base of hind femur pale yellowish white, middle trochanter and adjacent apex of middle coxa brown. Venter black, with ventrites VIII and IX brown.

Structural characters: Head of moderate length, declivant anteriorly, with weakly impressed median line; length 0.32, width 0.75; length of eye along inner margin 0.35, anterior/posterior interocular space, 0.15/0.43. Pronotum long, greater than dorsal length of head, leaving mesonotum barely exposed, width 1.00, length 0.60; mesonotum lacking foveae, length along midline 0.10; metanotum length along midline 0.13. Abdominal tergites I–VI dull, without shining areas, abdominal tergites VII and VIII shining; lengths of tergites I–VIII, respectively: 0.15: 0.15: 0.15: 0.10: 0.10: 0.12: 0.20: 0.25.

Entire dorsum and laterotergites covered with fine, appressed pale pubescence, intermixed with scattered long, erect black setae on head, lateral thorax, and dorsal abdomen; legs and antennae thickly clothed with very short gold setae, scattered long, stout, erect black setae present on anterodorsal faces of antennal segments I and II, anterior margins of fore, middle and hind femora and tibiae, posterior margins of fore and middle femora; fore and middle trochanters lacking pegs or teeth; fore femur with dorsal margin very weakly sinuate, ventral margin straight; fore tibia slightly expanded and ventrally flattened on distal one-fourth; middle femur and tibia with margins straight, not flattened or otherwise modified; hind trochanter bearing 2–4 small dark pegs ventrally; hind femur moderately incrassate, bearing two parallel rows of teeth, ventral row lying in area covered by infolded hind tibia and consisting of approximately 10 tiny, closely appressed black pegs basally, followed by 3 larger black teeth of gradually increasing size near mid-femur, then by 8 very tiny black teeth extending to femoral apex, dorsal row of teeth commencing near middle of femur with a moderately large, acute black tooth, followed by 8 smaller black teeth of progressively declining size toward femoral apex, these two parallel rows of teeth flanked by rows of scattered long, slender, erect pale setae; hind tibia straight, inner surface bearing an irregular row of 15–18 very small dark teeth ( Figs. 222, 223 ).

Venter of head with jugum bearing 8–10 very small black denticles; prothorax lacking denticles; meso- and metasternum flat, not sculptured, mesoternum with V-shaped patch of long gold setae centrally, the apex of this patch directed anteriorly; abdominal ventrite I lying in vertical orientation, ventrite II broadly carinate along longitudinal midline, ventrites III–VI broadly domed, ventrally convex, ventrite VII with a pair (1 + 1) of weak depressions to either side of midline, ventrites II–VI bearing numerous long, very fine pale setae in broad patch along longitudinal midline.

Male paramere small, bean-shaped, distal section broadly curving upward, bearing scattered short, stout setae along ventral margin ( Fig. 224 ). Male proctiger short, broad, with basolateral lobes weakly developed; distolateral lobes barely expressed; distal cone well developed, width appoximately half that of basal portion of proctiger, apex blunt, broadly rounded ( Fig. 225 ).

Lengths of antennal segments I–IV: 0.70: 0.45: 0.55: 0.50.

Lengths of leg segments as follows: femur, tibia, tarsal 1, tarsal 2, tarsal 3 of fore leg, 0.80: 0.95: 0.02: 0.01: 0.20; of middle leg, 1.30: 0.57: 0.05: 0.42: 0.60; of hind leg, 1.17: 1.30: 0.02: 0.05: 0.25.

Wingless female: Similar to wingless male in general structure and colour, with following exceptions: central section of pronotum depressed, with small, sharp carina along longitudinal midline; mesonotum barely exposed, angled downward at 20° angle; metanotum broadly exposed, horizontal; abdomen highly folded and foreshortened, tergite I horizontal, tergites II and III angled sharply downward, tergites IV–VIII angled sharply upwards and greatly shortened; first and second visible connexival segments vertical, dorsal margins parallel and thickly set with short, black setae, connexival segments IV–VII folded inward and forward, highly foreshortened ( Figs. 202 , 221 ); abdominal ventrite VII, gonocoxae and proctiger folded upward into a nearly vertical orientation. Hind femur weakly incrassate, bearing row of 5 medium to small black teeth of progressively decreasing size starting a point two-thirds removed from base and extending to posterior apex.

Winged male: Similar to wingless male in general structure and coloration, with following exceptions: pronotum greatly enlarged, width 1.15, length 1.10, completely covering meso- and metanotum, anterior margin bearing transverse dark orange patch anteromedially behind head vertex, bounded laterally by pale silvery pruinose areas; humeri enlarged, slightly protrusive laterally; posterior pronotal lobe broadly domed, lacking obvious foveae, posterior margin broadly angular, bearing scattered long, semi-erect black setae; forewings uniformly medium brown with veins darker brown, extending past apex of abdomen when intact, bearing 3 closed cells, consisting of two elongate cells in basal half of the wing followed by a single much smaller distal cell near the middle of the wing, set laterally behind the outer basal cell. Hind femur less swollen and incrassate than in wingless male.

Winged female: Similar to winged male in general body form and coloration; pronotum width 1.35, length 1.15.

Etymology. The name “yela ” is a noun in apposition, and refers to the traditional Melanesian name for Rossel Island, the type-locality.

Distribution. Louisiade Archipelago; endemic to Rossel Island ( Fig. 240 ). The species range as presently known occupies the Rossel Island area of freshwater endemism (Area 39) as delineated by D. Polhemus & Allen (2007).

Discussion. Rhagovelia yela is the most anomalous member of the R. papuenis group so far known, with a strikingly modified female abdominal morphology that cannot be confused with any other Rhagovelia species occurring in the greater New Guinea region. The terminal segments of the female abdomen are transversely folded and angled upward, so that the proctiger occupies a dorsal position ( Figs. 202 , 221 ), and due to this foreshortening the body length is less than twice the body width when measured from above (1.76/1.00). This morphology is very similar to that seen in members of the Rhagovelia diabolica group from Madagascar ( Polhemus & Andersen 2010, and in R. abbreviata Zettel , a Philippine species in the R. sumatrensis group ( Zettel et al. 2020), although these morphologies are apparently convergently evolved, since species in those groups have other diagnostic character state assemblages, that clearly separate them from R. yela and the R. papuensis group as a whole.

In contrast to the female, the male of R. yela has a general morphology rather typical of the R. papuensis group in general ( Fig. 220 ), and lacks any particularly divergent body or leg modifications. The male paramere is bean-shaped ( Fig. 224 ), again typical of the R. papuensis group, although the basolateral lobes of the proctiger are rather weakly developed in comparison to other species included here ( Fig. 225 ).

Ecological notes. For a general discussion of the Woa River type-locality, see the preceeding discussion under R. mbo . The type series of R. yela was taken skating on pools along small tributaries to the main stream ( Fig. 167 ) and in sheltered areas along the main channel margin ( Figs. 226 , 302 ).

Figures

FIG 202. Rhagovelia yela, wingless female, dorsal habitus; specimen from Rossel Is., Woa River, CL 7196. Young Sohn illustration.

FIG. 167. Woa River tributary, Rossel Is., Milne Bay Province, Papua New Guinea, CL 7196, habitat for R. mbo n. sp.

FIGS. 220–225. Rhagovelia yela n. sp., structural details; specimens from Rossel Is., Woa River, CL 7196. 220. Wingless male, dorsal habitus. 221. Wingless female, dorsal habitus. 222. Male right hind leg, posterior view. 223. Male right hind leg, dorsal view. 224. Male left paramere, outer lateral view. 225. Male proctiger, dorsal view.

FIG. 226. Woa River, Rossel Is., Milne Bay Province, Papua New Guinea, CL 7196, type-locality for R. yela n. sp., and habitat for R. woa n. sp. and R. mbo n. sp.

FIG. 240. Distributions of species in the R. yela subgroup in the Louisiade Islands, and R. suloga on Woodlark Island.

FIG. 302. Woa River, Rossel Is., Milne Bay Province, Papua New Guinea, CL 7196, type-locality for R. woa n. sp.