HOLOTYPE: OUMNH, ♂: MALAYSIA, Sabah, Lahad Datu, Ulu Segama For Res, Coupe 81 logging area, 04º58.660’N 117º53.410’E, iii.2005, FIT 2º Forest.
PARATYPES: 1♂ & 2 ♀♀, MALAYSIA: Sabah, Lahad Datu, Ulu Segama For Res, Danum Valley Forest Centre, 04º57.9’N 117 º48.1’E, 200 m alt, xi.2005 FIT, coll Mann, Slade & Villanueva, Slade & Villanueva OUMNH-2005-051 (in OUMNH). – 2 ♀♀, MALAYSIA, Borneo, Sabah, Ulu Segama Forest Reserve, Danum Valley Conservation area ca. 10 km from Danum Valley F.C., Borneo Raingorest (sic.) Lodge area Plot 3, 12.III.2004, F.I.Trap, ca. N 05º02 E 117º45.55’, Leg. E. Slade & J. Villanueva, OUMNH-2005-062, E. Slade colln. Oxford University Museum of Natural History (OUMNH) (in OUMNH). – 1 ♂ & 2 ♀♀, MALAYSIA, Borneo, Sabah, Ulu Segama Forest Reserve, Danum Valley Conservation area, ca. 10 km from Danum Valley F.C., Borneo Rainforest Lodge area, 8.IV.2004, F.I. Trap, Plot 3, ca. 05º02' N 117º45.55’E, Leg. E. Slade & J. Villanueva OUMNH-2005-062, E. Slade colln. Oxford University Museum of natural History (OUMNH) 9N (in OUMNH, 1 paratype in RCL, 1 paratype in MHNG). – 2 ♂♂, SABAH, Danum Valley, B. R.L. f.i.t., 14-16.II.2007, G. de Rougemont (in RCL).
ADDITIONAL MATERIAL SEEN: 1 ex.: Malaysia, Sabah, Tawau, 11-17.x.2012, 4.66N 117.6E, 100 m Alt, Coll. C.L. Gray, SAFE project area, F.I.T Riparian forest, strip in oil palm, OUMNH -213-056 (in OUMNH).
TAXONOMY: This new species belongs to the nigerrima group sensu Assing 2012 according to its colour, puncturation and conformation of the aedoeagus.
DESCRIPTION
Length of body: 8-9 mm; length of fore-body: 4.2 mm.
Head, pronotum and abdomen black, the posterior margins of abdominal tergites narrowly and obscurely reddish; elytra light or dark brown, the posterior third to half more or less strongly infuscate.
Habitus (fore-body): Fig. 1. Labrum and antennae dark brown; legs dark testaceous.
Head transverse, 4/5ths wider than long, the vertex shiny, with several large setiferous punctures near eyes, a continuous transverse row of smaller punctures along base, and irregularly scattered micro-punctures on entire disc, sparser in the middle. Eyes large and salient, twice as long as temples measured to posterior angle of head. Antennae about 2.9 mm long, antennomeres 5-9 with very narrow bases, club-shaped.
Pronotum only slightly transverse, very slightly broader than head, with an inner discal series of about 5 punctures, an outer series of 4 larger punctures, and 3-4 marginal punctures; sparse scattered micro-punctures exceedingly small, scarcely visible.
Elytra much longer and broader than pronotum, with an entire sub-marginal carina and two rows of about 10 discal punctures each, those of outer row coarser than inner row, in addition to a juxta-sutural row of small punctures and a row of about 10 punctures on declivous lateral surfaces. Pro-tarsi broadly dilated in both sexes.
Abdomen a little narrower than elytra, finely and not very densely punctuate.
Male: abdominal sternite VII (Fig. 1b) with a small, shallow apical emargination; sternite VIII (Fig. 1c) with a deep narrow emargination. Aedoeagus (Fig. 1a) characteristic, the dorsal blade very broad, apically sub-truncate, about as long as ventral blade, the latter with a conspicuous inwardly curving apical process on either side, and a sub-apical process bearing two ventral and two lateral spines.
REMARKS: P. borneensis n. sp. most closely resembles P. transversicollis Assing from Thailand and P. separanda Assing from north India, especially in the colour of the elytra, but is a smaller insect than either of those and with a characteristic aedoeagus.