Camponotus inquilinus

Currently, no records of C. inquilinus exist outside of Brunei. All examined specimens were found in artificial nests (#27 and #29) placed in the vicinity of the Kuala Belalong Field Studies Centre (KBFSC) in May 2014. The nests were constructed out of wooden stakes with holes drilled into them to create an internal cavity (for illustrations and details of construction, see Laciny et al. 2017, 2018). Nest #29 contained a colony consisting only of C. inquilinus, which allowed the sampling of minor workers, major workers, gynes and brood. The pupae exhibited cocoons, which is consistent with the current definition of the genus Camponotus (Ward et al. 2016). Nest #27 was occupied by a colony of the undescribed Colobopsis cylindrica group species Colobopsis sp. “nrSA” of the Colobopsis saundersi clade. Within this nest sample, a single minor worker specimen of C. inquilinus was found among minor workers of C. sp. “nrSA” (Laciny et al. 2017). It was presumably mistaken for a conspecific Colobopsis cylindrica group worker during sampling, due to its close resemblance in size and coloration. This finding further strengthens the hypothesis of an inquiline lifestyle closely connected to the exploding ants of the Colobopsis cylindrica group.

Identification
Minor worker: Bicoloured species; head and mesosoma reddish brown, the latter in some specimens with infuscated areas; gaster black. Entire dorsum with long standing setae. Vertex hardly domed. Clypeus basally slightly emarginated, with median carina in basal half. Flagellum of normal length. Pronotum reticulated, on shiny sides sculpture slightly reduced but still visible; with long standing setae. Dorsal outline of pronotum moderately convex, of mesonotum and anterior propodeum straight.

Major worker: Colour similar as in minor, but head rather yellowish clay-coloured. Setae on head very short, on mesosoma, petiole and gaster moderately long. Head squared, sculpture consisting of large punctures and very fine reticulation on frons, vertex and sides where the punctures are spaced. Eyes small. Frontal carinae high. Clypeus and genae with confluent punctures, giving the head a rugose appearance. Sculpture of mesosoma, petiole, and gaster as in minor.

The minor worker of C. inquilinus can be recognized by colour (Figs. 1, 2) in combination with a normally shaped vertex (Fig. 3) and long white standing setae on entire dorsum. The major is similarly coloured, except for the yellow head. Its head (Fig. 7) is very stout, dorsally with short setae and very dense, confluent puncturation, very similar to some species of Colobopsis. In gynes, the head resembles that of the major worker, but with less pronounced features.

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

Nomenclature

 *  inquilinus. Camponotus (Myrmamblys) inquilinus Zettel & Laciny, 2018: 130, figs. 1-10 (w.q.) BRUNEI.

Type Material
(BRM, NHMW): 8 minor workers (#1114–1121), 3 major workers (#1111–1113), and 1 dealate gyne (#1110), same nest series; 1 minor worker (#1173), same locality, artificial nest 27, 16.IV.2015, leg. A. Kopchinskiy, #362.
 * Holotype (minor worker #1122; BRM) from Brunei, Temburong, Kuala Belalong Field Studies Centre, artificial nest 29, 5.IV.2015, leg. A. Kopchinskiy, #346/347.
 * Paratypes