Naddia barclayi, Rougemont, 2016

Rougemont, G. de, 2016, New Bornean Staphylinidae (Coleoptera), Linzer biologische Beiträge 48 (1), pp. 559-572 : 564-566

Naddia barclayi nov.sp. (Fig. 4)

♀ Holotype: BORNEO, Sabah, 1240 m, Crocker Range , IV.2013, Kota Kinabalu → Tambunan, N5º51’33.7" E116º17’24.1" General collecting / BMNH{E} 2013-58, M.V.L. Barclay, B.H. Garner, H. Mendel & A. Giusti / BMNH(E) 1222076 [ NHML].

D e s c r i p t i o n: Length: 14.7 mm; length of fore-body: 8.6; length of head along central axis: 2.7; total length of head: 3.2; diameter of eye: 9; length of pronotum: 2.8; breadth of pronotum: 2.7; length of elytron: 3.2; breadth of elytra: 3.5. Body, mandibles and legs entirely black, labrum and palpi brown. Fore-body with some exceedingly sparse and short scattered pale pubescence and black setae of varying length; labrum and antennae with longer pale pubescence. Head transverse, the temples dilated; eyes small, prominent although displaced towards dorsal surface of head, much shorter than temples; sculpture moderately coarse, forming parallel rugae on middle of disc and frons, confused and vermiculate on sides; sides of head with rather dense dark setae directed sideways or slightly anteriad. Antennae short, antennomere III longer than II, IV and V sub-globose, V larger than IV, VI-X increasingly transverse, X slightly asymmetrical. Pronotum as long as broad, widest in anterior half, the sides strongly retracted in posterior half; sculpture coarse, the umbilicate punctures enclosed singly or in groups by mostly longitudinal confluent rugae, the centre with an interrupted narrow impunctate mid-longitudinal line; anterior margins between neck and anterior angles with fairly dense short, fine setae and 5-6 long setae on anterior angles. Scutellum densely punctured, with a velvety mat of black pubescence. Elytra quadrate, the sculpture confused, the large umbilicate punctures only clearly visible here and there among vermiculate rugae and pubescence; pubescence and setae black, but antero-lateral parts of elytra with some very sparse scattered short brassy setae. Abdominal tergites very coarsely punctured, the punctures largely obscured by dense black pubescence and setae; punctures on first tergites round, becoming increasingly elongate posteriad. Sides of tergites III-V with short erect brassy setae, the following tergites without such setae. Tergite III with an antero-median triangular patch of black pubescence; tergites IV-V with such black pubescence on entire middle half of tergites. Tergite VIII with numerous longer black setae in addition to pubescence.

M a l e: unknown.

Because of its colour, coarse puncturation and medium size this new species runs to N. borneensis from eastern Sabah in the key to the Bornean species ( Rougemont 2014), but differs in its larger size, proportionately smaller and more prominent eyes, and the sculpture of the head and pronotum which is coarser, with more confluent rugae; N. barclayi also lacks the patch of coppery pubescence on the humeral areas of the elytra which is characteristic of N. borneensis . Its sculpture and pubescence more closely resemble those of the much larger (22 mm) N. aureomontis Rougemont , also from the Crocker Range. Apart from its smaller size, N. barclayi nov.sp. differs from N. aureomontis by the more confused pattern of rugae on the head (rugae coarser and more regularly parallel in aureomontis) and the much coarser and deeper puncturation of the abdominal tergites.

Naddia barclayi ’s eponymous collector, Max Barclay, Curator and Collection Manager at the Natural History Museum in London, provided the circumstantial information that he "stole the beetle from some ants that were carrying it back to their nest" (kleptoparasitism as a collecting technique!). A 90 second video clip of the abduction shows about ten ants attached to the still living or freshly killed beetle’s legs, antennae and pygidium and manoeuvring it rapidly over rough terrain. In these pictures the colour patterns of the beetle, which are created by the coloured pubescence, are strikingly brighter than they appear in the dead mounted specimen, whatever the kind or angle of lighting projected on the latter. The sparse short pale pubescence on the lateral half of the elytra makes these appear grey, in contrast to the deep, almost bluish-black head and pronotum; in the video the 3 rd, 7 th and 8 th tergites appear to bear brilliant white markings, yet the specimen has no fasciae of silvery pubescence, such as exist in some other species, that might produce such an effect. These differences, which have been observed in other species, are not due to any physical post-mortem alteration, but probably to rapidly changing angles of illumination created by motion on microsculpture or pubescence that accentuate the contrasts of colours through effects of reflection and refraction.

E r r a t u m: in the key to the Naddia of Borneo in ROUGEMONT 2014 the line at the bottom of page 1740 ("Elytra black or fuscous, sometimes slightly rufescent…") should lead to dichotomy 7, not 11 as printed.

Plate 2: (4) Naddia barclayi ; (5) Ontholestes lowi ; (6) Ontholestes superbus ; h: habitus, al: aedoeagus in lateral view; av: aedoeagus in ventral view.