Crematogaster chhangi

This species is only known from the type locality. Specimen labels state "arboreal" but otherwise nothing is known about the biology of this species.

Identification
Hosoishi and Ogata (2014) - A member of the Crematogaster fraxatrix group. This species is similar to Crematogaster fraxatrix, but can be distinguished by the dorso-ventrally flattened propodeal spiracles and acutely developed subpetiolar process in the worker caste. The COI divergence between C. chhangi and C. fraxatrix did not seem relatively high (8.1–10.8 % K2P distances) (cf. Blaimer 2012a), but the two species are clearly separated from each other by the characters shown above.

Distribution based on Regional Taxon Lists
Oriental Region: Cambodia.

Castes
Known only from the worker caste.

Nomenclature

 *  chhangi. Crematogaster (Crematogaster) chhangi Hosoishi & Ogata, 2014: 61, figs. 1-2 (w.) CAMBODIA.

Worker
Measurements and indices. HW 0.64–0.83; HL 0.64–0.75; CI 100–111; SL 0.57–0.61; SI 73–86; EL 0.13–0.16; PW 0.37–0.42; WL 0.7–0.78; PSL 0.13–0.18; PtL 0.17–0.21; PtW 0.16–0.19; PtH 0.13–0.15; PpL 0.11–0.12; PpW 0.14–0.18; PtHI 65–82; PtWI 89–100; PpWI 127–150; WI 82–95 (holotype and eight paratype workers measured).

Workers presumably monomorphic. Posterior corners of head rounded. Anterior clypeal margin slightly concave in the median portion. Compound eyes not projecting beyond lateral margins of head in full face view. Scape reaching posterior corner of head. Antennal club 3-segmented. Pronotal dorsum with distinct ridges laterally. Mesonotal dorsum with lateral ridges. Mesonotum not higher than pronotum in lateral view; forming same dorsal outline with pronotum in lateral view. Metanotal groove straight in dorsal view, deep and forming a concave region between mesonotum and propodeum. Propodeal spiracles oval, flattened dorso-ventrally, located on the lateral sides of propodeum; the horizontal diameter more than two times larger than the vertical diameter. Propodeal spines developed long, directed upward and straight. Petiole broader in the middle portion. Subpetiolar process acutely developed. Postpetiole weakly bilobed, but without longitudinal median sulcus. Petiole slightly wider than postpetiole in dorsal view. Erect pilosity sparse. Scape with abundant erect to suberect setae. Dorsal face of head with suberect setae. Clypeus with suberect setae; one pair of longer setae directed medially on anteriormost portion. Anterior clypeal margin with one single setae and one pair of longer setae, mixed with some shorter setae on the sides. Mesosoma with sparse erect setae. Fourth abdominal tergite with erect to suberect sparse setae. Dorsal surface of head generally smooth and shining, but feeble rugulae between frontal carinae; longitudinal rugulae surrounding antennal sockets and on gena. Clypeus weakly striated with longitudinal rugulae. Promesonotum striated with feeble rugulae. Lateral surface of pronotum smooth and shining. Mesopleuron sculptured. Lateral surface of propodeum generally smooth, but with feeble rugulae on the lower portion. Body color brown.

Type Material
Holotype worker: pinned. Original label: CAMBODIA, Koh Kong, 11°31'N, 103°09'E, 19.v.2012, S. Hosoishi leg., SH12-Cam-70, arboreal; deposited at THNHM. Eight paratype workers: pinned, same data as holotype; deposited at, , , , , , ,.

Etymology
This species is dedicated to Mr. Phourin Chhang, Forestry Administration of Cambodia, who helped with field surveys in Cambodia.