Tetramorium kraepelini

Known from a few forest habitats including rubber plantations, collections records show samples being taken from litter samples.

Identification
A member of the Tetramorium scabrosum-species group.

Bolton (1977) - A widespread but apparently not very common species, kraepelini shows some variation over its range. Collections are not complete enough as yet to decide if any of these variations are of significance and in consequence I have retained all the samples under a single species. Specimens from the Philippines approach the holotype most closely as in these the peduncle of the petiole is relatively narrow and the node of the petiole in profile narrows dorsally quite conspicuously. In specimens from Japan and China the peduncle of the petiole tends to be broader and the node less narrowed above. In these specimens also the petiole node in dorsal view tends to be more globular and less distinctly transverse than in specimens from elsewhere. Closely related species occur in Japan and Java (Tetramorium tanakai and Tetramorium parvum respectively); these are best separated by the characters given in the key.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Philippines. Oriental Region: Taiwan, Vietnam. Palaearctic Region: China, Japan.

Nomenclature

 *  kraepelini. Tetramorium kraepelini Forel, 1905c: 15 (w.) INDONESIA (Java). Senior synonym of yanoi and material of the nomen nudum eidmanni referred here: Bolton, 1977: 117. Senior synonym of tanakai: Imai, Kihara, Kondoh, et al. 2003: 136; of amia: Terayama, 2009: 162.
 * amia. Tetramorium mixtum r. amia Forel, 1912a: 53 (w.) TAIWAN. Status as species: Bolton, 1977: 113 (redescription); Wang, M., Xiao & Wu, 1988: 267. Junior synonym of kraepelini: Terayama, 2009: 162.
 * yanoi. Tetramorium yanoi Santschi, 1937h: 376, figs. 8-10 (w.) JAPAN. Junior synonym of kraepelini: Bolton, 1977: 117.
 * tanakai. Tetramorium tanakai Bolton, 1977: 119 (w.q.) JAPAN. Junior synonym of kraepelini: Imai, Kihara, Kondoh, et al. 2003: 136.

Worker
Bolton (1977) - TL 2.1-2.3, HL 0.52-0.64, HW 0.46-0.58, CI 87-93, SL 0.34-0.40, SI 68-74, PW 0.34-0.44, AL 0.56-0.72 (16 measured).

Mandibles striate, anterior clypeal margin entire, arched. Frontal carinae distinct to well behind the level of the eyes but occipitally tending to merge with the other sculpture. Antennal scrobes moderately developed, forming conspicuous though quite shallow and broad impressions on the side of the head. Eyes relatively large, maximum diameter c. 0.13-0.17, about 0.26-0.30 x HW. Propodeal spines longer than metapleural lobes, acute, in some populations with a tendency to be slightly upcurved apically. Metapleural lobes triangular and acute. Petiole node in profile with the dorsal length less than the height of the tergal portion, the node tending to become narrower dorsally. In dorsal view the petiole node usually broader than long, less commonly about as broad as long. Dorsum of head predominantly or completely finely longitudinally rugulose to the level of the posterior margins of the eyes, behind which a reticulum is present. Ground sculpture of head a weak, superficial punctulation. Dorsal alitrunk finely reticulate-rugulose. Petiole and post petiole nodes usually both unsculptured, but in some specimens the petiole may show traces of feeble sculpture. Gaster unsculptured. All dorsal surfaces of head and body with fine standing hairs, the alitrunk with some hairs which are distinctly elongate. Antennal scapes with numerous short hairs and with a spaced row of longer, more conspicuous hairs on the leading edge. Dorsal (outer) surfaces of hind tibiae with elongate erect or suberect hairs. Colour varying from uniform yellowish brown to light mid-brown, sometimes the gaster slightly darker than the alitrunk.

Type Material
Bolton (1977) - Holotype worker, Java: Bogor (=Buitenzorg), 24.ii-12.iii.1904 (K. Kraepelin) [examined].