Philonthus muluensis, Rougemont, 2016

Rougemont, G. de, 2016, New Bornean Staphylinidae (Coleoptera), Linzer biologische Beiträge 48 (1), pp. 559-572 : 562-563

Philonthus muluensis nov.sp. (Fig. 2)

Philonthus sp. C . HANSKI & HAMMOND, 1986: 18.

3 Holotype: Borneo : Gunung Mulu, I. Hanski Camp 4, 1700-2300 m, ‘237’ [ NHML] ; 90 paratypes; some bear the same label as the holotype but camp number variously 3 or 4, and with different last number (tube number); others are labelled "BORNEO, Gunung Mulu N.P., Camp 4 [or 3], tube [no.], I. Hanski 2011 [Holotype and 72 paratypes in NHML; 5 paratypes in OUMNH; 10 paratypes in CRO, 3 paratypes in LML] .

As is the case with P. hanskii nov. sp., other specimens, plus incomplete bodies and fragments of many others were found in Hanski’s 2011 samples from high altitude sites on Gunung Mulu; 499 specimens were collected in 1978 and about 360 in 2011.

D e s c r i p t i o n: length: 6.2-7.4 mm. Head, pronotum and and scutellum black; anterior 1/3 rd of elytra red, posterior 2/3 rds black, the posterior margins narrowly yellow; abdominal urites III-VI black, the posterior margins of tergites narrowly reddish, urites VII-IX entirely pale red; labrum and mouthparts brown; antennomeres I-IX black, the base of II yellowish, X-XI yellowish brown to yellowish white; legs testaceous, the distal 1/3-1/2 slightly infuscate; all pubescence and setae black. All dorsal surfaces glossy, devoid of microsculpture. Head a sub-orbicular, a little transverse, the sides slightly retracted before broadly rounded postero-lateral angles; eyes large, longer than temples, not prominent; puncturation consisting of 2 punctures on the inner lateral margins of eyes, a pair of anterior discal punctures between the anterior ocular punctures, a pair of posterior discal punctures spaced like the anterior pair, and 5-6 punctures in post-ocular area. Antennae moderately long (1.9 mm), antennomeres I-IV elongate, III slightly longer than II, V-VI subquadrate, VII-X transverse. Pronotum slightly elongate, widest at middle, the sides rounded; puncturation consisting of a pair of discal series of 4+1 small punctures snf 3-4 irregular punctures between the discal series and the anterior lateral setiferous puncture. Scutellum wuth 8-9 large deep punctures. Elytra about a long as wide, broadest posteriorly; puncturation fine and sparse; lateral and posterior margins each with about six long setae in addition to pubescence. Abdominal tergites glossy, the puncturation consisting only of a row of closely set larger punctures along centre of basal line of tergites IV and V, a transverse irregular row of very small punctures on middle of tergites, and a row of small, slightly asperate punctures along posterior margins. First metatarsomere longer than II and III together, slightly longer than V.

M a l e: protarsi dilated; abdominal sternite VIII with a broad shallow emargination extending little more than 1/8 th the length of tergite; aedoeagus (Figs 2al, 2av), 1.1 mm long, the median lobe slightly widened distally before narrowing to a long blunt point; paramere (Fig. 2p) abruptly narrowed at mid-length, the apex pointed and bearing two short lateral rows each of about 8 small sensory peg setae.

Philonthus muluensis nov.sp. is easily distinguished from several other species on Gunung Mulu and elsewhere in Borneo and southeast Asia with similar colour pattern of the fore-body by the entirely clear red abdominal segments VII-IX.

Like P. hanski nov.sp., this species is a common specialist predator in dung and carrion confined to high altitudes on Gunung Mulu.

Plate 1: (1) Philonthus hanskii ; (2) Philonthus muluensis ; (3) Hesperus margaretae ; h: habitus, al: aedoeagus in lateral view; av: aedoeagus in ventral view; p: paramere.