Enithares bosavi, 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 : 154-156

Enithares bosavi new species

( Figs. 3 , 15 , 19 , 63 )

Type material examined. Holotype, male (dissected): PAPUA NEW GUINEA, Southern Highlands Prov., small rocky stream in primary rainforest on N. slope of Mt. Bosavi , 1250 m., 06°32′43′′S, 142°50′23′′E, water temp. 19° C., 17 March 1995, 11:00–15:00 hrs., CL 7026, D. A. Polhemus ( BPBM).

Description. Male: Length 11.20 mm, width across pronotum 4.40 mm.

Coloration: Ground color dark brown ( Fig. 15 ). Vertex creamy white; frons light brown with a pale blue patch immediately above labrum and extending upward along inner margins of eyes. Pronotum with anterior third dark brown; central section with creamy white transverse fascia traversing area between pronotal foveae; posterior half black. Scutellum dark brownish-black, somewhat more embrowned on lateral angles. Hemelytra with clavus and corium greyish hyaline appearing darker due to dorsal color showing through; wing membrane dark fumate brown. Legs yellowish brown, anterior edges of fore tibia, middle femur and hind femur narrowly margined with dark brown. Venter brown, with coxal plates tan.

Structural characters: Head broadly rounded anteriorly when viewed dorsally. Head length 1.00; greatest width 3.50, equal to 0.79 pronotal width; anterior width of vertex 1.30, equal to 1.3× head length. Synthlipsis 0.85, about 0.65 anterior width of vertex and clearly shorter than pronotum. Pronotal length along midline 1.30, humeral width 4.40, lateral margins convex, posterior margin weakly sinuate. Dorsal margin of pronotal fovea directed caudad behind eyes ( Fig. 15 ). Nodal furrow curved weakly cephalad, removed by 2.0× its length from membranal suture, length 0.60, distance to membranal suture 1.20.

Front and hind legs typical for genus, lacking unusual modifications. Middle trochanter rounded. Middle femur with single large subapical tooth, bordered basally by about 12 small black pegs, distally by about six similar pegs. Hind femur strongly dorsoventrally flattened when viewed laterally. Lengths of leg segments as follows: fore fe-mur–tibia–tarsal 1–tarsal 2 = 2.00/2.10/0.70/0.40; middle femur–tibia–tarsal 1–tarsal 2 = 2.80/2.20/0.90/0.50; hind femur–tibia–tarsal 1–tarsal 2 = 4.50/3.60/1.80/0.80.

Ventral abdomen with metaxyphus elongate triangular, slightly concave, tip acuminate ( Fig. 3 ).

Male genitalia when viewed laterally ( Fig. 19 ) with proctiger angular; pygophore with posteroventral angle forming nearly a right angle bearing a prominent setal tuft, posterior lobe broad and blunt, notched on dorsal margin, posteriorly setiferous; paramere elongate, apex rounded, exceeding dorsal margin of posterior process on pygophore; lateral arm of basal plate with distal section broadly curving, apex acute; aedeagus semicircular, with numerous transverse folds.

Female: Unknown.

Etymology. The name “bosavi” represents a noun in apposition, and refers to Mt. Bosavi, an isolated volcano lying south of the central mountain ranges in a remote area of Papua New Guinea.

Discussion. The genitalic morphology of E. bosavi is similar to that of E. stylata , which has a blunt, dorsally notched posterior lobe on the pygophore (PL), an elongate paramere with a rounded apex, and tapered, curving lateral arms on the basal plate (LABP). However, the paramere in E. stylata is basically straight, versus gently curving anterad as in E. bosavi , and the LABP is far more elongate, and slightly hooked at the apex (compare Figs. 19 , 37 ). Enithares stylata is also a larger species, with body lengths ranging from 11.75–13.00 mm, whereas the only known male of E. bosavi is 11.20 mm in length. Enithares bosavi is also similar to E. atra Brooks , which also possesses a blunt, dorsally notched (PL) and an elongate paramere with a rounded apex. The major difference between the two species lies in the shape of the LABP which is upwardly curving, tapering, and apically acute in E. bosavi , versus backwardly curving, distally expanded and apically truncate in E. atra (compare Figs. 17, 19 ).

Ecological notes: Enithares bosavi has to date been taken only from first order, upper elevation streams on Mt. Bosavi , an isolated volcano south of the New Guinea central ranges ( Fig. 63 ), lying in the Papuan Gulf Foreland area of freshwater endemism (Area 25) as defined by D. Polhemus & Allen (2007). The type locality was a small, rocky, heavily shaded headwater stream with cold, clear water, dropping along a moderate but steady gradient through undisturbed montane rain forest. The bed substate consisted of large, mossy rocks, with cobbles and gravel in the intervening runs. The single type specimen of E. bosavi was taken from a flowing pool near the stream’s headwaters .

Figures

FIGURE 63. Distribution of species in the E. atra and E. bakeri groups on New Guinea and nearby islands. Circles = E. bakeri Brooks, square = E. bosavi, triangles = E. loria Brooks.

FIGURES 2–7. Enithares species, metaxiphus. 2. E. arfak n. sp.; specimen from Indonesia, West Papua Prov., Mupi River, CL 2646. 3. E. bosavi n. sp.; holotype specimen from Papua New Guinea, Southern Highlands Prov., Mt. Bosavi, CL 7206. 4. E. insularis n. sp.; specimen from Papua New Guinea, Milne Bay Prov., Fergusson Island, CL 7181. 5. E. kasim n. sp.; specimen from Indonesia, West Papua Prov., Kasim, CL 2630. 6. E. orsaki n. sp.; specimen from Papua New Guinea, Madang Prov., Reinduk, CL 7036. 7. E. papua n. sp.; specimen from Papua New Guinea, Central Prov., Tekadu, CL 7157.

FIGURES 9–15. Enithares species in the E. atra group, dorsal habitus photographs. 9–10. Enithares orsaki n. sp., male and female; specimens from Papua New Guinea, Madang Prov., Reinduk, CL 7036. 11–12. Enithares atra Brooks, male and female; specimens from Papua New Guinea, Central Prov., Dorobisoro, CL 7260. 13–14. Enithares insularis n. sp., male and female; specimens from Papua New Guinea, Milne Bay Prov., Fergusson Island, CL 7181. 15. Enithares bosavi n. sp., holotype male; specimen from Papua New Guinea, Southern Highlands Prov., Mt. Bosavi, CL 7206.

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.