Tetramorium, Mayr

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 : 130-131

Diagnosis of Tetramorium TETRAMORIUM Mayr

Tetramorium Mayr, 1855: 423 . Type-species: Formica caespitum L., 1758: 581 , by subsequent designation of Girard, 1879: 1016.

Xiphomyrmex Forel , 1887: 385 [as subgenus of Tetramorium ]. Type-species: Tetramorium {Xiphomyrmex) kelleri Forel , loc. cit.; by subsequent designation of Wheeler, 1911: 175. [Synonymy by Bolton, 1976: 359.]

For a full statement of the generic synonymy of Tetramorium (= Tetrogmus Roger, = Xiphomyrmex Forel , = Atopula Emery, = Macromischoides Wheeler, = Sulcomyrmex Kratochvil, = Lobomyrmex Kratochvil) see Bolton, 1976: 359 - 365.

Diagnosis of worker and female. Myrmicine ants of the tribe Tetramoriini which have the following combination of characters. Mandibles with 2 - 3 enlarged apical teeth followed by a row of 4 (rarely more) denticles, so that at least 6 (usually 7) teeth are present altogether. Sting with an apical or apicodorsal translucent lamelliform appendage which may be spatulate, triangular, dentiform or pennant-shaped. Lateral portions of clypeus raised into a sharp ridge or shielding wall in front of the antennal insertions. Palp formula 4, 3 at maximum. (Usually with this count, very rare reductions to 4, 2; 3, 3 and 3, 2 are known.) Antennae with 11 or 12 segments, with an apical club of 3 segments. Body hairs never regularly branched bifid, trifid or quadrifid, usually simple but very rarely absent or bizarre.

Diagnosis of male. Myrmicine ants of the tribe Tetramoriini which have the following combination of characters. Mandibles dentate. Antennae with 10 or 11 segments, the second funicular an elongate fusionsegment; funiculus filiform. Palp formula 4, 3 at maximum as worker / female. Body hairs as worker / female, never regularly branched.

A more complete definition of the genus has been given previously (Bolton, 1976), along with a discussion of the genus-level synonymy of Tetramorium . An abridged version of this synonymy is noted above as in both the regions at present under consideration some species occur to which the generic name Xiphomyrmex was formerly applied. During the first part of this study it was found that this name, based only on the reduced antennomere count of 11 in worker and female castes (as opposed to 12), had no significance as it occurred in a number of widely divergent groups whilst other characters of generic significance remained fixed throughout those groups and throughout groups in which the antennae had 12 segments. In consequence Xiphomyrmex was sunk as a junior synonym of Tetramorium .

In the regions now under consideration Tetramorium is the only tetramoriine genus with endemic species, although tramp-species of the genus Triglyphothrix Forel are known to occur (certainly Tr. lanuginosa (Mayr) and very probably Tr. kheperra Bolton ). These are distinguished from Tetramorium by their possession of numerous branched hairs, bifid or trifid, on all surfaces of the body. Finally, the parasitic genus Anergates Forel , whose host is Tetramorium caespitum (L.) , is known from New Jersey, U. S. A., but this is hardly likely to be confused with Tetramorium as it lacks a worker caste, has an apterous, pupoidal male and is morphologically very distinct (see Bolton, 1976 and included references).