Enithares papua, Polhemus, 2020

Polhemus, Dan A., 2020, Nine new species of Enithares (Heteroptera: Notonectidae) from New Guinea, with distributional notes on other species and an updated world checklist, Zootaxa 4772 (1), pp. 132-182 : 139-144

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Enithares papua

new species

Enithares papua new species

( Figs. 7 View FIGURES 2–7 , 20 View FIGURES 16–21 , 22 View FIGURE 22 , 25, 26 View FIGURES 23–29 )

Type material examined. Holotype, male (dissected), PAPUA NEW GUINEA, Central Prov. , Yaniwe River and small tributary streamlets at Tekadu, 300 m., water temp. 24° C., 21 January 2001, 12:00–16:30 hrs., 07°40′36′′S, 146°33′05′′E, CL 7157, D. A. Polhemus ( BPBM). GoogleMaps

Paratypes: PAPUA NEW GUINEA, Central Prov.: 9 males, 9 females, 1 immature, same data as holotype, CL 7157, D. A GoogleMaps . Polhemus ( USNM, BPBM) ; 2 males, 6 females, Owen Stanley Range, Hane River , 1.8 km. SSE of Fane, 1310–1370 m., 8°34′00′′S, 147°05′10′′E, water temp. 19 °C., 3 October 2003, 10:30–13:30 hrs., CL 7253 GoogleMaps ,

D. A. Polhemus ( USNM); 1 male, Owen Stanley Range, Mas River , 2.0 km. SW of Fane, 1235 m., 8°33′25′′S, 147°04′04′′E, water temp. 20 °C., 5 October 2003, 10:00–13:30 hrs., CL 7257, D GoogleMaps . A. Polhemus ( USNM). Southern Highlands Prov.: 2 males (dissected), 3 females, small rocky creek in disturbed forest, approx. 1.0 km. N. of Tubage , NE of Moro, 1000 m., 06°19′43′′S, 143°17′30′′E, water temp. 21° C., 14 March 1995, 14:30–15:00 hrs.; 22 March 1995, 13:00–13:30 hrs., CL 7022, D GoogleMaps . A. Polhemus ( USNM, BPBM); 1 male (dissected), small forest tributary to upper Mubi River at Swinging Bridge, nr. Tubage , NE of Moro, 900 m., 06°19′31′′S, 143°17′57′′E, water temp. 20° C., 14 March 1995, 11:00–13:00 hrs., CL 7020, D GoogleMaps . A. Polhemus ( USNM); 1 female, seeping rock face and roadside streamlets, approx. 2 km. S. of Moro oil camp on road to Iagifu Ridge , 950 m., 06°22′10′′S, 143°13′21′′E, 21 March 1995, 13:30–16:00 hrs., CL 7031, D GoogleMaps . A. Polhemus ( USNM) .

Description. Male: Length 10.40 mm, width across pronotum 3.90 mm.

Coloration: Ground color dark greyish-brown ( Fig. 25 View FIGURES 23–29 ). Vertex and frons varying from uniform medium brown to uniform creamy white. Pronotum medium brown, sometimes paler brown along anterior margin. Scutellum black to dark brown, sometimes becoming creamy white on posterior half. Hemelytra dark grey, often with with anterior margins of clavus bordering scutellum broadly pale, forming a chevron-shaped fascia; wing membrane dark fumate brown. Legs brown, anterior edges of fore and hind femora margined with black. Venter brown.

Structural characters: Head broadly rounded anteriorly when viewed dorsally. Head length 1.15; greatest width 3.10, equal to 0.79 pronotal width; anterior width of vertex 1.00, equal to 0.87× head length. Synthlipsis 0.60, about 0.60 anterior width of vertex and clearly shorter than pronotum. Pronotal length along midline 1.20, humeral width 3.90, lateral margins convex, posterior margin weakly sinuate. Dorsal margin of pronotal fovea directed caudad behind eyes. Nodal furrow nearly straight, removed by 2.0× its length from membranal suture, length 0.70, distance to membranal suture 1.40.

Front and hind legs typical for genus, lacking unusual modifications. Middle trochanter rounded. Middle femur with single large, elongate, sharp subapical tooth, bordered basally by about 13 small black pegs, distally by about 4 similar pegs. Lengths of leg segments as follows: fore femur–tibia–tarsal 1–tarsal 2 = 1.50/1.80/0.70/0.30; middle femur–tibia–tarsal 1–tarsal 2 = 2.60/2.30/0.70/0.40; hind femur–tibia–tarsal 1–tarsal 2 = 4.20/3.50/1.50/0.70.

Ventral abdomen with metaxyphus triangular, slightly concave, tip acuminate ( Fig. 7 View FIGURES 2–7 ).

Male genitalia when viewed laterally ( Fig. 20 View FIGURES 16–21 ) with proctiger dorsal apex weakly sinuate, apex truncate; posterior lobe of pygophore with posteroventral angle obtuse, bearing a prominent tapering setal tuft, posterior lobe of pygophore erect, apex broad and blunt, posteriorly setiferous, slightly notched anteriorly on dorsal margin; paramere elongate, slightly tapering, apex rounded, reaching to dorsal margin of posterior lobe; lateral arm of basal plate stout, elongate, apex weakly angular, ventral margin slightly keeled near apex; aedeagus semicircular, with numerous transverse folds.

Female: Length 10.00, width across pronotum 3.95 mm. Similar to male in general structure and coloration, with following exceptions: coloration generally paler, with all or part of vertex, frons, pronotum and scutellum creamy white ( Fig. 26 View FIGURES 23–29 ).

Etymology. The name “papua” is a noun in apposition, and refers to the geographic range of this species, which occurs in river basins draining to the Gulf of Papua.

Discussion. Among the New Guinea Enithares assemblage, E. papua appears allied to E. atra , E stylata , and E. elongata , as well as E. bosavi and E. peninsularis newly described herein, on the basis of the large, blunt PL with a notch anterodorsally, and the well-developed paramere that reaches to or slightly exceeds the dorsal margin of the PL ( Figs. 17, 19, 20, 21 View FIGURES 16–21 , 35, 37 View FIGURES 35–40 ). Among this group of species, E. papua can be readily distinguished by its prominent LABP, which is elongate, weakly sinuate, and keeled apicoventrally ( Fig. 20 View FIGURES 16–21 ). The paramere shape is also slightly different from these other species, being slightly expanded basally, then gradually tapering distally to a rounded apex ( Fig. 20 View FIGURES 16–21 ).

Enithares papua is similar in many respects to E. insularis , differing primarily in the structure of its male genitalia. The shapes of the PL and parameres are close, but the posterior paramere margin in E. papua is gently bowed, whereas in E. insularis it is straight, and the apex of the paramere in E. insularis is more rounded. The male proctiger has a curved ventral margin in both species in lateral view, but in E. papua the apex comes to an acute angle, rather than being bluntly rounded as in E. insularis (compare Figs. 18, 20 View FIGURES 16–21 ). The structure of the LABP differs between the two species and is the most diagnostic gentalic character, with the distal portion of the LABP narrowed in E. insularis and then apically expanded to form a small bulb, whereas in E. papua the LABP is of nearly the same thickness throughout its length, terminating in a truncate apex with a small, angular point posteroventrally (compare Figs. 18, 20 View FIGURES 16–21 ). In addition to these genitalic differences, the male fore femur of E. insularis has a very thick and extensive pad of short, dense black setae which runs the length of the anteroventral margin ( Fig. 20 View FIGURES 16–21 ); this setal pad is less prominently developed in E. papua , and is composed of pale brown to silvery setae.

Ecological Notes. At the Tekadu type locality (CL 7157) E. papua was taken from a seepage-fed side channel in gravel and cobbles adjacent to the main Yaniwe River, which was swift and rocky. These shallow, shaded pools were devoid of fish, and also supported Hydrometra eioana J. Polhemus & Lansbury and an undescribed Microvelia species. At the Swinging Bridge locality (CL 7020), E. papua was taken from a small, steeply descending rainforest streamlet on the south bank of the Mupi River. Individuals occupied small pools connected by tiny riffles and cascades. At a nearby stream south of Tubage (CL 7022) this species was found in a small, heavily shaded forest stream with small pools connected by riffles (D. Polhemus 1995).

Enithares papua is currently known from intermediate elevations in south-flowing drainages of the Owen Stanley Range and southern central highlands of Papua New Guinea ( Fig. 22 View FIGURE 22 ). Collection records span the Auga, Lakekamu, and Kikori river basins, indicating that this species will also be shown to occur in the intervening Purari River basin as well. By contrast, this species was not encountered in the south-flowing Ajkwa River basin of Indonesian New Guinea, to the west of the Digul River, despite comprehensive surveys in that drainage (D. Polhemus & J. Polhemus 2000). Based on these records, E. papua occupies the South Papuan Peninsula Foreland and Papuan Gulf Foreland areas of freshwater endemism (Areas 25 and 30) as defined by D. Polhemus & Allen (2007).


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