Bioacoustics of Enithares nigra

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 .