Enithares arfak, 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 : 157-158

Enithares arfak new species

( Figs. 2 , 47, 48 , 51 , 66 )

Type material examined. Holotype, male (dissected): INDONESIA, Irian Jaya Prov. [Papua Prov.], New Guin- ea, Mupi River above Warkomi , Arfak Mountains , 38 km. S. of Manokwari , 150 m., 18 October 1991, 01°06′42′′S, 134°05′04′′E, CL 2646, D. A. Polhemus and J. T. Polhemus ( BPBM) . Paratypes: INDONESIA, Irian Jaya Prov. [Papua Prov.], New Guinea: 9 males (1 dissected), 7 females, same data as holotype ( USNM); 2 males (1 dis- sected), 5 females, small rocky stream at Aimasi Hulu, Arfak Mountains , 65 km. SW of Manokwari, 140 m., 0°54′41′′S, 133°47′39′′E, water temp. 25° C., 19 October 1991, CL 2649, D. A . Polhemus and J. T. Polhemus ( BPBM, USNM, LIPI) . Other material examined (not paratypes): 5 females, Prafi River at Warmari, 48 km SW of Manokwari, Arfak Mtns., 215 m, 0°57′31′′S, 133°53′16′′E, water temp. 26.5° C., CL 2652, 19 October 1991, J. T. & D. A . Polhemus ( BPBM) .

Description. Male: Length 8.50 mm, width across pronotum 3.10 mm.

Coloration: Ground color brown to blackish, with varying extent of pale marking on scutellum and hemelytra ( Fig. 47 ). Vertex and frons creamy white to yellowish; frons bearing a pair (1+1) of small roughly circular brown patches near anterior apex, and another roughly triangular brown patch above base of labrum; lower section of frons adjacent to labrum sometimes suffused with pale blue; labrum dark brown, sometimes dark yellow centrally. Pronotum with anterior half between pronotal foveae creamy white to tan; posterior half brown to black; propleura creamy white. Scutellum creamy yellowish-white, suffused to varying degrees with dark brown to black at anterolateral angles and centrally. Hemelytra brown to black, with outer half of clavus, outer half of corium, and sometimes inner margin of clavus bordering scutellum white; wing membrane uniform fumate brown, translucent. Legs yellowish brown, anterior edges of all femora margined with dark brown to black. Venter brown, with coxal plates greyish.

Structural characters: Head broadly rounded anteriorly when viewed dorsally. Head length 1.10; greatest width 2.50, equal to 0.80 pronotal width; anterior width of vertex 0.70, equal to 0.63× head length. Synthlipsis 0.50, about 0.71 anterior width of vertex and clearly shorter than pronotum. Pronotal length along midline 0.95, humeral width 3.10, lateral margins convex, posterior margin weakly sinuate. Dorsal margin of pronotal fovea directed caudad behind eyes ( Fig. 47 ). Nodal furrow curved weakly cephalad, removed about 2.0× its length from membranal suture, length 0.50, distance to membranal suture 0.90.

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 4 similar pegs. Lengths of leg segments as follows: fore femur–tibia–tarsal 1–tarsal 2 = 1.60/1.50/0.50/0.25; middle fe-mur–tibia–tarsal 1–tarsal 2 = 1.90/1.65/0.55/0.50; hind femur–tibia–tarsal 1–tarsal 2 = 3.00/2.50/1.10/0.80.

Ventral abdomen with metaxyphus triangular, slightly concave, tip acute ( Fig. 2 ).

Male genitalia when viewed laterally ( Fig. 51 ) with proctiger truncate; posterior lobe of pygophore with posteroventral angle obtuse, bearing a prominent setal tuft, lobe of proctiger erect, posteriorly setiferous, apex broadly rounded, not notched on dorsal margin; paramere small, subovate, not even reaching half distance to apex of posterior lobe; lateral arm of basal plate strongly bent, roughly L-shaped, dorsal margin broadly curving, apex turned slightly upward; aedeagus semicircular, with numerous transverse folds, bearing serrate row of dark teeth along ventral margin.

Female: Length 8.20 mm.; width across pronotum 3.00 mm. Similar to male in general structure and coloration, but with pale coloration on pronotum, scutellum and hemelytra more extensive ( Fig. 48 ).

Etymology. The name “arfak” is a noun in apposition, and refers to the Arfak Mountains type locality in far northwestern New Guinea.

Discussion. Enithares arfak n. sp., E. kasim n. sp., E. megalops Lansbury and E. paramegalops Lansbury appear to be a closely knit group of sister species, all of which share certain common male genitalic character states, including a highly reduced paramere; a rounded or angular apex on the PL, without a dorsal notch; and a relatively simple morphology of the LABP, with the apex not expanded or acuminate ( Figs. 49–51 ). The genitalic morphology of E. arfak is similar to that of E. megalops , but differs in the somewhat more broadly rounded apex of the PL, the slightly larger paramere, and the different shape of the LABP, which is more strongly bent and L-shaped in E. arfak and has the apex slightly upturned in lateral view (compare Figs. 49, 51 ). Enithares arfak is also a somewhat larger and stouter species, with body lengths ranging from 8.5–8.9 mm, versus 7.0– 7.7 mm in E. megalops .

Ecological notes. Enithares arfak belongs to a set of four putatively related species that have partially segregated but also partially overlapping ranges in the Vogelkop Peninsula of western New Guinea. Within this grouping, E. paramegalops as currently interpreted has an extensive range, occurring from the Celebes eastward through the Moluccas to the Papuan Gulf lowlands of Papua New Guinea ( Fig. 66 ). By contrast, E. arfak n. sp., E. kasim n. sp., and E. megalops Lansbury have more limited ranges in western New Guinea and the Moluccas. Enithares megalops occurs from Ambon to the Lengguru Fold Belt of the New Guinea “bird’s neck” ( Fig. 66 ); E. kasim ( Fig. 67 ) has been taken only at the western end of the Vogelkop; and E. arfak has so far been collected only in the Arfak Mountains of the eastern Vogelkop ( Fig. 66 ). These patterns of putative endemism, though intriguing, should be considered provisional, however, since too little collecting has been done to establish the precise geographic ranges of these species with any confidence. Based on current records, however, E. arfak appears confined to the Vogelkop Highlands areas of freshwater endemism (Area 5) as defined by D. Polhemus & Allen (2007).

The Mupi River at the type locality was a fast, clear, powerful river coming out of the Arfak Mountains through a bed of boulders, rocks and gravel. The stream is known to the local people for its cold waters. The heavily scoured main channel was relatively poor habitat for aquatic Heteroptera, but quiet, spring-fed side channels harbored a variety of species, including Enithares arfak . This species was also taken deeper into the Arfak Mountains from a small, clear stream issuing from primary rain forest adjacent to oil palm plantations at Aimasi Hulu. The habitat at this latter site consisted of shaded pools and small riffles in a bed of rocks and sand, with water depth of 18–45 cm.

Figures

FIGURE 66. Distribution of species in the E. megalops group on New Guinea. Triangles = E. megalops; circles = E. paramegalops Lansbury; pentagons = E. arfak.

FIGURE 67. Distribution of species in the E. megalops group on New Guinea. Square = E. kasim n. sp.; circles = E. nigra Lansbury; triangles = E. alexis Lansbury; pentagons = E. vulgaris Lansbury.

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 41–48. Enithares species in the E. megalops group, dorsal habitus photographs. 41–42. Enithares megalops Lansbury, male and female; male specimen from Indonesia, West Papua Province, Kasim, CL 2620, female paratype specimen from Indonesia, West Papua Prov., Bomberai Peninsula. 43–44. Enithares paramegalops Lansbury, male and female; male specimen from Papua New Guinea, Gulf Province, Kopi, CL 7000, female paratype specimen from Indonesia, Papua Prov., Enarotali. 45–46. Enithares kasim n. sp., male and female; specimens from Indonesia, West Papua Province, Kasim, CL 2630. 47–48. Enithares arfak n. sp., male and female; specimens from Indonesia, West Papua Province, Mupi River, CL 2646.

FIGURES 49–54. Enithares species in the E. megalops group, male genitalic complex, left lateral view. 49. Enithares megalops Lansbury; specimen from Indonesia, West Papua Prov., Kasim, CL 2620. 50. Enithares paramegalops Lansbury; specimen from Papua New Guinea, Gulf Prov., Kopi, CL 7000, 51. Enithares arfak n. sp.; specimen from Indonesia, West Papua Prov., Mupi River, CL 2646. 52. Enithares kasim n. sp.; specimen from Indonesia, West Papua Prov., Kasim, CL 2630. 53. Enithares nigra Lansbury, specimen from Papua New Guinea, Southern Highlands Prov., Moro, CL 7024. 54. Enithares vulgaris Lansbury n. sp.; specimen from Indonesia, Papua Prov., Biak Island, CL 2643.