Tetramorium bicarinatum

Bolton, B., 1979, The ant tribe Tetramoriini (Hymenoptera: Formicidae). The genus Tetramorium Mayr in the Malagasy region and in the New World., Bulletin of the British Museum (Natural History) Entomology 38, pp. 129-181 : 164

The bicarinatum -group

Antennae with 12 segments, sting appendage triangular, dentiform or pennant-shaped. Anterior clypeal margin with a median notch or impression. Median portion of clypeus with three principal longitudinal carinae, often without other sculpture but sometimes with another much weaker pair of carinae. Mandibles variously sculptured, smooth to striate. Frontal carinae strongly developed, reaching back almost or quite to the occipital margin. Propodeal spines always strongly developed, straight to somewhat upcurved along their length. First gastral tergite commonly costulate basally. Basic sculpture throughout the group a strong rugoreticulum. Pilosity usually abundant, elongate and fine; short truncated hairs absent.

This group contains a number of the larger and more conspicuous members of the genus. The Oriental / Indo-Australian region has a total of 13 species and the Ethiopian region about 15.

One species of the group, bicarinatum , is a highly successful tramp-species and has been recorded from all over the world except for the Ethiopian region. Two other members of the group have some tramping ability, insolens and pacificum . The former closely resembles bicarinatum and has been found to date in Britain, Germany and the U. S. A., but always as an introduction or living in zoological or botanical gardens. The latter occurs sporadically in California where it has been recorded by M. R. Smith (1943) and Creighton (1950). The species has an enormous range in the Indo-Australian and Oriental regions and seems to be present on most of the Pacific island-systems, so it is hardly surprising that it should occur occasionally on the west coast of the United States.