A New Exocrine Gland in Novomessor (Hymenoptera: Formicidae) and its Possible Significance as a Taxonomic Character

The genus Novomessor is comprised of only three species: N. albisetosus, N. cockerelli and N. manni. The first two species are rather common in the Southwestern United Staes and Northern Mexico (CREIGHTON 1950, 1955), and the latter has been collected along the Pacific coast of Mexico (KANNOWSKI 1954). The forms of Novomessor were originally described as Aphaenogaster, and recently W . L. Brown (1974) suggested that they should be placed back in that genus. He pointed out that "the characters supposed to distinguish the two genera are not very strong when one considers the whole world fauna of this complex". Brown's arguments were especially supported by his reexamination of Novomessor manni Wheeler and Creighton (1934) and Aphaenoggster ensifera Fore1 (1899), which he found to be synonymous. He concluded his reasoning by stating ". . .the example of A. ensifera and N. manni may help to alert myrmecologists to the kind of change to be expected of a worldwide reclassification. One of the changes in status resulting from this study is of course the return of cockerelli and albisetosus to their original generic assignment in Aphaenogaster". In the course of a comparative study of communication mechanisims in Novomessor, we discovered a new complex exocrine gland. Since this gland is a very distinct character, it should be given considerable weight in the future taxonomic assessment of the species possessing it.