Tetramorium quadridentatum species group

From Bolton (1980)

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Diagnosis

This is a convenience-group of 6 species assembled to hold those species with sculptured mandibles and an entire clypeal margin (without median notch or impression) which do not fit into any other group. Other characters which they have in common include frontal carinae which extend back beyond the level of the posterior margins of the eyes, relatively short antennal scapes (SI < 90; range 77-89), a strongly nodiform petiole and a dentiform or pennant-shaped appendage on the apex of the sting.

The species grouped together here for convenience are in general not closely related but the group is in fact based on a core of three definitely allied species, quadridentatum, unicum and viticum, which share a distinctive petiole node shape, are coarsely sculptured, quite densely hairy and have fairly large eyes (0.23-0.29 x HW). All three of these species seem to be arboreal, based on personal observation in the case of quadridentatum; on Wheeler (1922: 192) for unicum, which he misidentified as meressei; and on Weber (1943: 373) for viticolum. The last two named are known only from their type-series, but the first is fairly widely distributed in west and central Africa, nesting in rot-holes in tree trunks and branches.

Peripheral to this complex is magnificum which, although lacking the distinctive node shape seen in the above, seems distantly related to them. The last two species included here, longoi and simulator, cannot be associated with any other group or with the above except that they have the few characters in common given at the top of this section. longoi appears to show affinity with the scabrosum-group of South East Asia, having bristly pilosity and freely projecting hairs on scapes and tibiae coupled with coarse sculpture and moderately sized eyes. Whether this is true relationship or convergence is not known.

T. simulator is one of the most peculiar members of the genus yet found in the region. It is a large, reddish, virtually unsculptured ant which lacks hairs of any description on the dorsal surfaces of the body. It has relatively short appendages, large eyes, deep antennal scrobes and heavy mandibles, and superficially it bears a close resemblance to members of the genus Decamorium. According to Arnold (1917: 298) it preys on termites and, as termites are the main prey of Decamorium (Bolton 1976; Longhurst, Johnson & Wood, 1979), the apparent relationship of appearance may be just a reflection of convergent characters acquired by adoption of a similar lifeway.