Camponotus concurrens

Identification
Minor worker: Trunk chiefly yellowish or pale orange; distal segments of antenna and parts of gaster brownish infuscated. Vertex highly domed. Clypeus at base broadly and shallowly emarginated and with a short, deep median impression; anterior margin straight. Flagellum slender. Mesosoma with reduced sculpture, shiny. Pronotum with short standing setae. Dorsal outline of pronotum strongly convex, of mesonotum and propodeum almost straight. – Major worker: Colour similar as in minor, head slightly darker. Head squared, shiny, with coarse puncturation; microsculpture evanescent except for area between high frontal carinae and eye. Eyes small. Clypeus with concave basal margin, a pair of large setiferous punctures near base, and a large shallowly depressed area apically. Reticulated sculpture of mesosoma more distinct than in minor, reduced only on pronotum. Petiole and gaster reticulated as in minor. Petiolar node more slender than in minor.

The minor of C. concurrens can be easily recognized by colour and the shiny, strongly convex pronotum. The major has a similar colour, but appears very different by a very shiny head (matt in minor), a reticulated microstructure of the mesosoma (except pronotum) and a moderately convex pronotum. Both castes can be distinguished from most other species (except Camponotus syaukanii) by short pronotal setae. These two species are very similar in structures and sculpture, although very different in colour, with C. syaukanii having a strongly infuscated mesosoma and petiole, and black gaster. Two clear differences are found in minor workers: Firstly, in C. concurrens, the anterior clypeal margin is straight, whereas in C. syaukanii it is distinctly protruded in the middle. Secondly, the strongly convex, “humped” pronotum of C. concurrens is evenly and moderately convex in C. syaukanii.

Specimens of C. concurrens from the Asian mainland differ from the type series from Borneo by a ground colour that is rather orange than yellowish, darker and slightly stouter funicular segments of antenna, and by a slightly lower, more stocky petiolar node. We consider these variations as intraspecific.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Malaysia. Oriental Region: Thailand.

Nomenclature

 *  concurrens. Camponotus (Myrmamblys) concurrens Zettel & Laciny, 2018: 141, figs. 22-31 (w.q.) BRUNEI.

Type Material

 * Holotype (minor worker #1787; NHMW) from Brunei, Temburong, Kuala Belalong Field Studies Centre, N 04°33', E 115°09', 60 m a.s.l., 6.IV.1994, leg. D.W. Davidson, #KB05-36.
 * Paratypes (NHMW, THNMH, CDF): 3 major workers (#1788–1790) and 2 alate gynes (#1791, 1792), same nest series as holotype; 2 minor workers (#1656, 1657), 2 major workers (#1654, 1655), Thailand, Chanthaburi Province, Pheao N.P., Troknong Waterfall, tropical rainforest, 24.XI.2003, leg. W. Jaitrong, #TH03-WJT502; 1 minor worker (#1658), Thailand, Loei Province, Phu Luang W.S., 13.V.2007, leg. S. Hasin, #SH07-TH; 1 minor worker, Thailand, Khao Yai N.P., 900–1000 m a.s.l., 20.V.2000, leg. Sk. Yamane; 1 minor worker (#1160), 1 major worker (#1161), Malaysia, Selangor, Kuala Lumpur, Ulu Gombak FSC, N 3.32466°, E 101.752717°, 240–270 m a.s.l., 21.I.1987, leg. W. H. O. Dorow, #SEA-0742.