Enithares nigra Lansbury, 1968

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 : 161

Enithares nigra Lansbury

( Figs. 53 , 60, 61 , 67 )

Enithares nigra Lansbury 1968: 395 .

Material examined. INDONESIA, Irian Jaya Prov. [Papua Prov.], New Guinea: 1 male, NW New Guinea, Wis- selmeren, Itouda [Itodah Lake, upper Elegeoboe River, 3°57′28′′S, 135°56′39′′E], Kamo Valley, 13 August 1955, J. L. Gressitt (holotype, BPBM); 6 males, 5 females, small rocky forest stream below PTFI Etna Bravo drill camp, 580 m, 3°58′09′′S, 134°59′45′′E, water temp. 23° C., 30 March 1997, 10:00–12:00 hrs., CL 7081, D. A . Polhemus and J. T. Polhemus ( USNM); 9 males (1 dissected), 23 females, 7 immatures, upper Kali Mati River, 10 km. N. of Fak Fak , 275 m., 2°52′50′′S, 132°18′00′′E, water temp. 23° C., 10 October 1991, CL 2633, D. A . Polhemus & J. T. Polhemus ( USNM, BPBM); 1 male (teneral), 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) . PAPUA NEW GUINEA, Southern Highlands Prov.: 7 females, imponded roadside stream in forest at Moro oil camp, 840 m., 06°21′54′′S, 143°13′56′′E, water temp. 25° C., 14 March 1995, 16:00–17:00 hrs.; 24 March 1995, 14:00–15:00 hrs., CL 7024, D. A . Polhemus ( BPBM); 1 female, rocky stream at Ludesa Mission, N. of Mt. Bosavi , 700 m., 06°27′57′′S, 142°50′31′′E, water temp. 23° C., 20 March 1995, 12:30–14:30 hrs., CL 7029, D. A . Polhemus ( BPBM) .

Discussion. The author has examined the holotype of this species, which is housed in the Bishop Museum. The dorsally bidentate PL of the pygophore ( Fig. 53 ) and the set of fine transverse ridges across the ventral surfaces of the two most anterior connexival segments in both sexes are diagnostic. The latter structures are suggestive of a component of a stridulatory mechanism, but this function has not been demonstrated. Although currently placed for taxonomic utility in the megalops group, this species may eventually prove to have different phylogenetic affinities when a more rigorous analysis is undertaken.

Ecological notes. Enithares nigra has a relatively broad geographic range within New Guinea, but is encountered only sporadically, in both lotic and lentic habitats. At the Ludesa Mission (CL 7029) near Mt. Bosavi in southwestern Papua New Guinea, E. nigra was taken from a fairly fast stream immediately west of the mission, flowing through a rocky, open channel with approximately 20–40 percent shading, and pools 1–2 m deep. The water was slightly turbid due to recent rains, although the local people indicated that the stream often ran clear.

The range of E. nigra is now known to extend eastward from the Vogelkop Peninsula along the southern side of New Guinea through the Bomberai Peninsula and Lengguru Fold Belt to at least the Kikori River basin of Papua New Guinea ( Fig. 67 ), occupying the Vogelkop Lowlands, Vogelkop Highlands, Vogelkop Anticlines and Papuan Gulf Foreland areas of freshwater endemism (Areas 4, 5, 6 and 25) as defined by D. Polhemus & Allen (2007). Surprisingly, it has not yet been taken in the Ajkwa River basin in the vicinity of Timika, in intervening southern Indonesian New Guinea, despite a set of intensive aquatic surveys in that area (D. Polhemus & J. Polhemus 2000).

The notation “Itouda′′ on the holotype locality label refers to Itodah Lake , lying at 3°57′28′′S, 135°56′39′′E, along the upper Elegeoboe River approximately 48 km west of Enarotali, at an elevation of 1550 m .

Figures

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 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.

FIGURES 56–62. Enithares species in the megalops and bakeri groups, dorsal habitus photographs. 56–57. Enithares bakeri Brooks; male specimen from Indonesia, Nusa Tenggara Timur Prov., Timor, Niki Niki, CL 2595, male specimen from Indonesia, West Papua Province, Kasim, Is., CL 2620. 58–59. Enithares vulgaris Lansbury, male and female; specimens from Indonesia, West Papua Province, Biak Is., CL 7039. 60–61. Enithares nigra n. sp., male and female; specimens from Indonesia, West Papua Province, Etna Bay, CL 7081. 62. Enithares loria Brooks, male; specimens from Indonesia, Papua Province, Siewa, CL 7085.