Mystrium

Bihn, J. H. & Verhaagh, M., 2007, A review of the genus Mystrium (Hymenoptera: Formicidae) in the Indo-Australian region., Zootaxa 1642, pp. 1-12 : 1

[[ Genus Mystrium Roger ]]

The genus Mystrium Roger is morphologically very peculiar within the poneromorph subfamily group and has the following combination of characteristics: the very wide head; spatulate or squamate hairs on the head; and long, narrow mandibles with a double row of teeth on the inner margins. Monophyly of the genus is strongly supported by a recent molecular phylogenetic study (Saux et al. 2004). Besides their bizarre morphology Mystrium ants have also evolved some unique biological traits. They have a unique defense mechanism in which they snap their mandibles to generate a powerful strike (Gronenberg et al. 1998; Moffett 1986). Molet et al. (2006) demonstrated that, in some species of Mystrium known from Madagascar, normal queens are replaced by wingless reproductives which are smaller than workers. Because Mystrium are rarely encountered, information on their general biology, ecology and behavior remains sparse. They are presumably predaceous like other species of the subfamily Amblyoponinae , although no direct evidence is available (Brown 1960).

The genus was erected by Roger (1862) with the description of the queen of M. mysticum . There are few species, all of which occur in the rainforests of the Old World. Most species are found in tropical Africa: six of them are restricted to Madagascar (and its adjacent islands, i.e. the Malagasy region sensu Bolton 1994) and one is recorded from continental Africa. Mystrium camillae Emery 1889 is widespread in the Indo-Australian region. Xu (1998) recently described M. oculatum from southern China, but we do not regard it as a distinct species. Since the first revision of Menozzi (1929) only Brown (1960) made some revisionary notes on the genus. Here we describe two new species of Mystrium from Papua and West Papua Province, Indonesia, and provide a review of the species known from the Indo-Australian Region.