Enithares peninsularis, 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 : 144-145

Enithares peninsularis new species

( Figs. 21 , 30–32 )

Type material examined. Holotype, male (dissected): PAPUA NEW GUINEA, Central Prov. , Owen Stanley Range, Udabe River headwaters, 1.75 km. WNW of Woitape, 1615–1645 m., 8°32′02′′S, 147°14′16′′E, water temp. 16.5–18.5 °C., 1 October 2003, 09:00–14:00 hrs., CL 7247, D. A. Polhemus ( BPBM) . Paratypes: PAPUA NEW GUINEA, Central Prov., 2 males, 7 females, same data as holotype, CL 7247, D. A. Polhemus ( USNM, BPBM) ; 3 males, 2 females, 1 immature, Owen Stanley Range, small hill streamlet, 1.3 km. SSE of Woitape , 1600

m., 8°33′00′′S, 147°15′34′′E, water temp. 17.5 °C., 2 October 2003, 08:30–09:15 hrs., CL 7248, D. A . Polhemus ( USNM, BPBM).

Description. Male: Length 12.20 mm, width across pronotum 4.60 mm.

Coloration: Ground color dark brown ( Fig. 31 ). Vertex and frons yellowish-orange; frons bearing a pair (1+1) of small irregular brown patches near anterior apex to either side of midline, and another roughly triangular brown patch along midline above base of labrum. Pronotum with anterior third lying between lateral foveae brown, bordered posteriorly by a creamy white transverse fascia, posterior half of pronotum dark brown. Scutellum dark brownish-black, posterior apex dark yellow. Hemelytra medium brown hyaline, certain areas appearing darker due to dorsal color showing through; wing membrane dark fumate brown. Legs yellowish brown, central portions of trochanters and femora, and anterior faces of fore tibia suffused with darker reddish-brown, hind femur narrowly margined with dark brown, a second similar narrow longitudinal stripe running parallel to this on ventral face. Venter brown, coxal plates margined with tan.

Structural characters: Head broadly rounded anteriorly when viewed dorsally. Head length 1.00; greatest width 3.60, equal to 0.78 pronotal width; anterior width of vertex 1.40, equal to 1.4× head length. Synthlipsis 0.98, about 0.70 anterior width of vertex and clearly shorter than pronotum. Pronotal length along midline 1.40, humeral width 4.60, lateral margins convex, posterior margin weakly sinuate. Dorsal margin of pronotal fovea directed caudad behind eyes. Nodal furrow curved weakly cephalad, removed by over 2.0× its length from membranal suture, length 0.60, distance to membranal suture 1.40.

Front and hind legs typical for genus, lacking unusual modifications. Middle trochanter rounded. Middle femur with single large subapical tooth, bordered basally by about 8 small black pegs, distally by about 4 similar pegs. Lengths of leg segments as follows: fore femur–tibia–tarsal 1–tarsal 2 = 2.00/2.00/0.80/0.40; middle femur–tibia–tarsal 1–tarsal 2 = 2.30/2.10/0.90/0.60; hind femur–tibia–tarsal 1–tarsal 2 = 4.80/4.00/1.80/1.10.

Ventral abdomen with metaxyphus elongate triangular, slightly concave, apex acuminate.

Male genitalia when viewed laterally ( Fig. 21 ) with proctiger roughly rectangular, apex angular; pygophore with posteroventral angle forming an obtuse angle bearing a prominent setal tuft, posterior lobe of pygophore well produced, dorsal margin truncate, slightly notched anterodorsally; paramere large, tapering, apex blunt, reaching to apex of posterior lobe; lateral arm of basal plate large, basal section gently curving, bearing an anteroventral process, distal section gradually tapering, apex blunt, rounded; aedeagus semicircular, with numerous transverse folds.

Female: Length 12.70 mm, width across pronotum 4.90 mm. Similar to male in general structure and coloration, but with pronotum and scutellum entirely yellowish-orange ( Fig. 32 ).

Etymology. The name “peninsularis” refers to the geographic range of this species, which is confined to the Papuan Peninsula.

Discussion. In terms of size, E. peninsularis is one of the largest Enithares species occurring on New Guinea, with body lengths in both sexes exceeding 12 mm. The genitalic morphology of E. peninsularis shares similarities to that of E. stylata , another high altitude species, particularly in regard to the blunt, dorsally notched posterior lobe on the pygophore (PL), and the elongate paramere with a rounded apex. However, the shape of the proctiger when viewed laterally is roughly rectangular in E. peninsularis , versus roughly triangular in E. stylata (compare Figs. 21 , 37 ). In addition, the shape of the LABP will immediately separate the two species, with that of E. peninsularis being stout and gently curving, with a blunt apex and a prominent ventral process, whereas that of E. stylata is more strongly curved and tapering, coming to an acute, slightly hooked apex, and lacks a ventral process (compare Figs. 21 , 37 ).

Ecological notes. At the type locality near Woitape (CL 7247), E. peninsularis was taken from the still waters of a deep, algae-filled side pool formed behind large boulders.

Enithares peninsularis appears to be restricted to the higher elevations in the Owen Stanley Range of the Papuan Peninsula ( Fig. 30 ). The only other Enithares species on New Guinea of similar large size is E. stylata , which is widespread through the central highlands of Papua New Guinea west of the Aure Scarp ( Fig. 30 ). Based on known records, E. peninsularis occupies the Owen Stanley Mountains area of freshwater endemism (Area 31) as defined by D. Polhemus & Allen (2007).

Figures

FIGURE 30. Distribution of species in the E. atra group on New Guinea. Square = E. ziwa n. sp.; triangles = E. stylata Lansbury; pentagon = E. peninsularis n. sp.

FIGURES 31–34. Enithares species in the E. atra group, dorsal habitus photographs. 31–32. Enithares peninsularis n. sp., male and female; specimens from Papua New Guinea, Central Prov., CL 7248. 33–34. Enithares tagula n. sp., male and female; specimens from Papua New Guinea, Milne Bay Prov., CL 7190.

FIGURES 16–21. Enithares species in the E. atra group, male genitalic complex, left lateral view. 16. Enithares orsaki n. sp.; specimen from Papua New Guinea, Madang Prov., Baitabag, CL 7034. 17. Enithares atra Brooks; specimen from Papua New Guinea, Central Prov., Dorobisoro, CL 7264. 18. Enithares insularis n. sp.; specimen from Papua New Guinea, Milne Bay Prov., Fergusson Island, CL 7181. 19. Enithares bosavi n. sp., holotype; specimen from Papua New Guinea, Southern Highlands Prov., Mt. Bosavi, CL 7206. 20. Enithares papua n. sp.; specimen from Papua New Guinea, Central Prov., Tekadu, CL 7157. 21. Enithares peninsularis n. sp.; specimen from Papua New Guinea, Central Prov., Woitape, CL 7248.

FIGURES 35–40. Enithares species in the E. atra and E. bakeri groups, male genitalic complex, left lateral view. 35. Enithares elongata Lansbury; specimen from Papua New Guinea, Morobe Prov., Wareo. 36. Enithares ziwa n. sp.; specimen from Indonesia, Papua Prov., Ziwa River, CL 7100. 37. Enithares stylata Lansbury; specimen from Papua New Guinea, Morobe Prov., Wau, CL 1817. 38. Enithares tagula n. sp.; specimen from Papua New Guinea, Milne Bay Prov. Tagula Is., CL 7190. 39. Enithares bakeri Brooks, specimen from Indonesia, West Papua Prov., Aimasi River, CL 2651. 40. Enithares loria Brooks; specimen from Indonesia, Papua Prov., Siewa, CL 7085.