A taxonomic revision of seed harvester ants of the Tetramorium solidum group (Hymenoptera: Formicidae) in southern Africa

Abstract

Ants of the Tetramorium solidum group occur in Africa, with the vast majority of species endemic to the arid regions of southern Africa. The first revision of the genus was published more than 30 years ago and ant surveys have since considerably expanded the number of specimens available for study. The revision of this group reveals five new species, expanding the total number to 19. Almost all the species in this group occur in the southern parts of the Afrotropical region, with the exception of T. setuliferum Emery, 1895 and T. rothschildi (Forel, 1907). These two species have broad distributions within African grasslands and savannas, with T. setuliferum occurring in southern Africa and T. rothschildi in East Africa and the Sahel. Five new species are described in this revision: T. aisha sp. nov., T. brigitteae sp. nov., T. duncani sp. nov., T. lerouxi sp. nov. and T. margueriteae sp. nov. An illustrated key is presented and descriptions of new species are provided, supported by montage images and distribution maps.

A new species in the Tetramorium solidum-group (Hymenoptera, Formicidae, Myrmicinae) from the Richtersveld National Park, South Africa, with an assessment of threats and conservation status

“…Terminology relating to adult morphology largely follows Hita Garcia and Fischer (2014) as used by Mbanyana et al (2018) with some differences as discussed below; descriptions of surface sculpture follow Harris (1979) . All measurements (in millimetres) and indices are presented as minimum and maximum, with arithmetic means in parentheses.…”

“…He listed 13 species, later assigning T. rothschildi (Forel, 1907) as the 14 th species in the group upon the synonymy of Triglyphothrix under Tetramorium ( Bolton 1985 ). The T. solidum -group was more recently revised by Mbanyana et al (2018) , who described five new species and presented an illustrated key to the 19 species then known. Another group-level revision in the near future is unlikely and description of a single additional species to enable identification and formal conservation assessment is thus justified.…”

“…A description of Tetramorium nama sp. nov. and an additional couplet to be used in conjunction with the existing key in Mbanyana et al (2018) to allow identification of the new species are therefore presented here. As this publication is intended to be used in conjunction with Mbanyana et al (2018) , the reader is referred to the latter for a full diagnosis and overview of the T. solidum species-group.…”

“…Members of the T. solidum -group are believed to be predominantly granivorous ( Bolton 1980 ; Mbanyana et al 2018 ), but no detailed studies on food preferences appear to have been done. The group is largely restricted to southern Africa and displays its greatest diversity in the arid south-western parts of this region, within which the RNP lies.…”

“… Tetramorium nama sp. nov. is described here and a modification to the key presented by Mbanyana et al (2018) to accommodate the additional species is provided. The potential threats to the species posed by alluvial diamond mining, livestock farming and climate change are discussed.…”