Enithares vulgaris Lansbury in Nieser & Chen 1991

Enithares vulgaris Lansbury

(Figs. 54, 58, 59, 67)

Enithares vulgaris Lansbury 1968: 403.

Material examined. INDONESIA, Irian Jaya Prov. [Papua Prov.], Biak Is.: 3 males, 3 females, Biak Is., Aiyin- dor River (trib. to Wari), 135 m., 0°52′49′′S, 135°58′59′E, water temp. 25° C., 12 January 1997, 15:45–16:30 hrs., CL 7039, D. A. Polhemus (USNM, BPBM); 43 males, 22 females, 9 immatures, Wafor River, N. of Biak, 30 m., 0°57′57′′S, 136°03′07′′E, water temp. 25° C., 16 October 1991, CL 2643, D. A. Polhemus & J. T. Polhemus (USNM, BPBM).

Discussion. Enithares vulgaris may be recognized by its small, almost triangular paramere (Fig. 54), the apically rounded PL (Fig. 54), the numerous small black spinules on the posterior margin of the proctiger (Fig. 54), and the shape of the LABP, which is broadly crescentic with a slightly produced and truncate apex (Fig. 54). The species is also strongly bichromatic, with predominantly pale and predominantly dark individuals intermixed in the same populations (Figs. 58, 59).

Ecological notes. This species is apparently endemic to the limestone island of Biak, lying off the northwestern coast of New Guinea (Fig. 67), and was previously known only from the type series collected there by J. L. Gressitt and T. C. Maa in 1959. Further surveys on Biak in the 1990s by the author and J. T. Polhemus determined that this species is locally abundant where encountered, as demonstrated by the series of 74 specimens taken at the Wafor River. Enithares vulgaris was also recorded from Celebes by Nieser & Chen (1991), but these authors subsequently conceded that this identification was in error (Nieser & Chen 1996), thus the species still appears to be a Biak endemic, although it probably also occurs on the closely adjacent island of Supiori as well. Based on our current understanding, this species is thus confined to the Biak-Supiori area of freshwater endemism (Area 8) as defined by D. Polhemus & Allen (2007).