Tetramorium rugigaster

The type material was collected from evergreen-forest litter and rotten wood samples.

Identification
A member of the Tetramorium scabrosum-species group.

Bolton (1977) - This species is very close to Tetramorium transversarium but is larger, more strongly sculptured and has the petiole node less massively developed. More distantly rugigaster is related to Tetramorium mixtum but in this species the tibiae lack long erect hairs, all which are present being short.

Distribution based on Regional Taxon Lists
Oriental Region: India.

Nomenclature

 *  rugigaster. Tetramorium rugigaster Bolton, 1977: 114, fig. 39 (w.q.m.) INDIA.

Worker
Holotype. TL 3.4, HL 0.78, HW 0.76, CI 97, SL 0.52, SI 68, PW 0.56, AL 0.92.

Mandibles striate; anterior clypeal margin entire. Frontal carinae long and strong, extending back well beyond the eye. The area constituting the scrobe distinctly less strongly sculptured than the remainder of the head and its boundaries well defined so that the scrobe is quite distinct. Eyes of moderate size, maximum diameter 0.16. Dorsal alitrunk evenly but shallowly convex in profile, metanotal groove absent. Propodeal spines in profile of moderate length, stout and acute. Metapleural lobes triangular and acute. Petiole blocky and massive, its shape in profile as in Fig. 39. In dorsal view the node distinctly broader than long, massive. Basal border of first gastral tergite in dorsal view with the lateral angles prominent and projecting forwards as a pair of blunt tubercles or teeth. Dorsum of head predominantly longitudinally rugulose anteriorly but from about the level of the eyes the rugulae becoming disorganized and the number of cross-meshes increases posteriorly so that a ruguloreticulum is present occipitally. Dorsal surfaces of alitrunk, petiole and postpetiole reticulate-rugulose. Basal half of first gastral tergite finely but conspicuously longitudinally rugulose with some anastomosis of the rugulae basally, first gastral sternite similarly sculptured. All dorsal surfaces of head and body with abundant long fine hairs. Leading edge of antennal scapes with a row of projecting hairs which are longer than the maximum width of the scape. Dorsal (outer) surfaces of hind tibiae with numerous erect or suberect hairs, the longest of which are distinctly longer than the maximum tibial width. Colour uniform deep reddish brown, the appendages yellowish brown.

Paratypes. As holotype but some lighter in colour. Size range TL 3.0-3.4, HL 0.72-0.82, HW 0.70-0.78, CI 92-97, SL 0.48-0.54, SI 68-73, PW 0.50-0.60, AL 0.80-0.94 (12 measured). Maximum diameter of eye C. 0.16-0.18.

Type Material
Holotype worker, India: Kerala State (W. Ghats), Kottiyoor, Wynaad Taluk 650 m, 7.iv.1969, evgrn forest (A. B. Soans & W. L. Brown). Paratypes. India: 4 workers with same date as holotype; 13 workers, 1 alate female and 4 males, Kerala State CW. Ghats), Silent Valley Reserve, 16 km W. of Mukkali, 9.iv.1969, moist evgn for., 1200 m, litter, rot. wood M244 CA. B. Soans & W. L. Brown) [parts of data on undersides of labels] (MCZC; ).

References based on Global Ant Biodiversity Informatics

 * Bolton, B. "The ant tribe Tetramoriini (Hymenoptera: Formicinae. The genus Tetramorium Mayr in the Oriental and Indo-Australian regions and in Australia." Bulletin of the British Museum (National History): Entomology series 36, no. 2 (1977): 68-151.
 * Dad J. M., S. A. Akbar, H. Bharti, and A. A. Wachkoo. 2019. Community structure and ant species diversity across select sites ofWestern Ghats, India. Acta Ecologica Sinica 39: 219–228.
 * Rajan P. D., M. Zacharias, and T. M. Mustak Ali. 2006. Insecta: Hymenoptera: Formicidae. Fauna of Biligiri Rangaswamy Temple Wildlife Sanctuary (Karnataka). Conservation Area Series, Zool. Surv. India.i-iv,27: 153-188.