Camponotus syaukanii

Only known from the type locality in Kalimantan, Indonesia.

Identification
Minor worker: Head and dorsal parts of mesosoma reddish brown; ventral parts of mesosoma, petiole, and gaster black; antenna orange, distally infuscated. Vertex highly domed. Basal margin of clypeus triangularly emarginated; anterior margin medially convex and shiny. Flagellum of normal length. Mesosoma with reduced sculpture, shiny. Pronotum with short standing setae. Dorsal outline of pronotum moderately 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 on 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.

This species is rather dark in colouration compared with Camponotus weiserti and Camponotus concurrens. The most closely related species is C. weiserti, but in the latter the mandible with a smaller striate area, in addition to colour difference. The minor worker of C. concurrens is easily separable from C. syaukanii by the strongly convex pronotum (see further notes under C. concurrens).

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

Nomenclature

 * . Camponotus (Myrmamblys) syaukanii Zettel & Yamane, in Zettel, Balàka, et al. 2018: 152, figs. 40-46 (s.w.) BORNEO (Indonesia: Kalimantan).

Worker
Minor

Holotype: HW 1.50; HL 1.76; SL 1.50; SW 0.16; EL 0.46; ML 2.22; HaL 0.16; FeL 1.86; CI 85; SI 100; EI 31; FeI 124. Ward’s Indices: ASM/HWex 0.32; ASM/CLW 0.73; CLW/CLL 1.15. Note that the holotype is extraordinarily large compared to other minor workers. Paratypes (n = 5): HW 1.24–1.36; HL 1.52–1.58; SL 1.49–1.58; SW 0.13–0.16; EL 0.38–0.40; ML 1.96–2.04; HaL 0.13–0.21; FeL 1.90–1.98; CI 82–90; SI 113–120; EI 29–31; FeI 142–153. Ward’s Indices: ASM/HWex 0.30–0.32; ASM/CLW 0.65–0.70; CLW/CLL 1.16–1.24.

Structures: Head in full-face view longer than wide, with strongly convex vertex. Clypeus distinctly wider than long; posterior margin triangularly incised at middle; anteriorly produced, with extreme anterior margin truncate. Eye large, weakly convex, not breaking lateral outline of head. Mandible with five teeth, which decrease in size toward base. Dorsum of head extensively and densely micropunctate; temple and gena covered with dense longitudinal microstriae; ventral face of head superficially microsculptured; occiput almost smooth, shiny. Clypeus densely micropunctured but its anterior narrow strip more weakly sculptured with a few pits from which setae arise. Mandible with microstriate area close to inner basal portion. Antennal scape long, with head in full-face view surpassing posterior margin of head by more than two fifths of its length; first funicular segment (pedicel) longer than second, as long as apical segment. Mesosoma in dorsal view widest at pronotum; mesonotum as wide as propodeum. Suture between pronotum and mesonotum distinct; suture between mesonotum and propodeum less pronounced. Posterior half of mesonotum and propodeum together dorsally forming rather sharp longitudinal ridge. Mesosoma in profile weakly convex dorsally; posterior portion of pronotum and mesonotum forming almost flat dorsal outline; propodeum sloping posteriad with only weak differentiation of dorsal from posterior face; posterior face (declivity) of propodeum sometimes margined laterally by blunt carinae near base. Propodeal spiracle very small, almost of the size of the mesothoracic spiracle. Mesosoma extensively with dense micro sculpture that is slightly larger than on head; lateral and posterior portions of pronotum and propodeal declivity more weakly sculptured and shiny. Petiole in frontal view apically shallowly but distinctly convex (in smaller minors) or almost flat (larger minors), in dorsal view short, its node shorter than wide, with transversely ridged summit; in profile node narrowed apically, as long as high, with short anterior face, anteriorly sloping dorsal face and rather steep posterior face. Gaster in dorsal view oviform, widest at second and third segments; first tergite with anterior margin evenly rounded; each tergite with very short (narrow) apical lamellate area. Gastral tergites 1–3 dorsally densely and finely sculptured,  scattered with slightly larger pits from which setae arise. Dorsa of tergites 4–5, ventral sides of all tergites and entire sternites weakly sculptured and shiny.

Pilosity: Almost entire body covered with short, white, appressed pubescence. All standing setae on body straight and whitish. Dorsum of head between frontal carinae and on vertex with many standing setae, longer on vertex than on frons. Gena without standing setae; clypeus with sparse standing setae over disk; in frontal view its anterior margin bearing long median seta and several pairs of shorter ones. Mandible in frontal view with many standing setae along masticatory, anterior and lateral margins. Antennal scape with dense suberect to appressed short hairs mixed with very sparse longer setae (the latter more easily visible in lateral view). Mesosoma in profile with sparse standing setae that are roughly paired; those on propodeum much longer than others; lateral side of mesosoma without such setae. Petiole with two (rarely three) pairs of long standing setae and unpaired much shorter ones. Gastral tergites and sternites with many standing setae that are sometimes slanting or weakly curved. Legs covered with short suberect to appressed hairs; dorsal and ventral faces of forecoxa, and ventral face of forefemur (occasionally) with a few long standing setae.

Colour: Head and mesosoma reddish brown to orange, but mesosoma with dark areas. Petiole and gastral dorsum generally much darker than head and mesosoma. Area with lighter colour variable among individuals of the same colony. Gaster often with red tinge (fourth and fifth tergites always dark brown to black). Antenna reddish brown. Legs dark reddish brown to blackish brown.

Major

Paratypes (n = 4): HW 1.91–1.96; HL 2.11–2.35; SL 1.30–1.37; SW 0.17–0.19; EL 0.47–0.50; ML 2.46–2.53; HaL 0.09–0.16; FeL 1.74–1.90; CI 82–91; SI 67–70; EI 25–26; FeI 90–98.

Structure: Head in full-face view almost rectangular, longer than wide, with weakly sinuated posterior margin and weakly roundly produced posterolateral corners. Frontal carina curved outwardly at midlength to form distinct frontal lobe; shallow median furrow present between frontal carinae. Clypeus much longer than wide; basal margin medially incised, laterally roundly convex; anterior two-thirds of clypeus with parallel lateral margins; anterior portion of clypeal disc lowered with short (narrow) apical strip that slightly extends forward; extreme anterior margin of the strip shallowly convex. Eye elongate, very shallowly convex, not reaching lateral margin of head. Antennal scape short, barely reaching posterolateral corner of head; first funicular segment as long as apical segment. Mesosoma similar to that of minor worker except in the following aspects: seen from above mesonotum not longitudinally ridged dorsally and ridge on propodeum more rounded than in minor worker; metanotum transversely rhombic, delimited from mesonotum and propodeum by distinct sutures. With petiole in frontal view dorsal outline of node almost flat. Gaster as in minor worker.

Pilosity: Similar to minor worker. Standing setae on frons and vertex relatively shorter than in the latter. Clypeus with one pair of stiff short standing setae near posterior margin; other parts of disc only occasionally with a few very short standing setae; anterior margin with median seta that is rather short but longer than lateral pairs. Mandible with several standing setae around bases of teeth and along anterior margin. Antennal scape covered with very short decumbent pubescence and several standing setae on anterior face. Standing setae on pronotum and mesonotum very sparse and short; those on propodeum much longer. Petiole with two to three pairs of standing setae and some shorter softer hairs; venter of petiole with dense short soft hairs. Standing setae on gastral tergites 1–3 short; those on tergites 4–5 and posterior margins of sternites much longer.

Colour: Head and anterior half of mesosoma reddish brown; rest of mesosoma, petiole, gaster and legs much darker (often blackish) but occasionally with reddish tinge to varying extent. Antennal scape reddish brown.

Type Material

 * Holotype (minor worker #1785; MZB) from Indonesia, Kalimantan, Tanah Tidung, Gunung Rian, hard dead branch, 26.III.2016, leg. Sk. Yamane & Syaukani, KM16-SKY-134.
 * Paratypes (MZB, SKYC, CZW, NHMW): 5 minor workers, 4 major workers, same nest series as holotype.

Etymology
The specific epithet, syaukanii, is dedicated to our Indonesian friend, Dr. Syaukani of Syiah Kuala University, Aceh, Indonesia.

References based on Global Ant Biodiversity Informatics

 * Zettel H., P. Balaka, S. Yamane, A. Laciny, L. Lim, and I. S. Druzhinina. 2018. New mimetic ants from Southeast Asia – the Camponotus (Myrmamblys) inquilinus group (Hymenoptera: Formicidae: Camponotini). Zeitschrift der Arbeitsgemeinschaft Osterreichischer Entomologen 70: 125-174.