The ant genus Tetramorium Mayr (Hymenoptera: Formicidae) in the Malagasy region—taxonomic revision of the T. kelleri and T. tortuosum species groups

摘要

The taxonomy of the T. kelleri and T. tortuosum groups is revised for the Malagasy zoogeographical region. Twenty-four species are recognised of which 18 are described as new and six re-described. This raises the species richness for the genus Tetramorium in the Malagasy region to 84 species. The T. kelleri group is endemic to the Malagasy region, and contains the two species T. ankarana sp. n. and T. kelleri Forel. The T. tortuosum group is distributed in most zoogeographical regions, but reaches its highest species richness in the Malagasy region with the 22 species treated herein. All species are endemic to the island of Madagascar. Based on morphological key characters, the group was divided into four species complexes. The largest species complex is the T. andrei complex with the nine species: Tetramorium ala sp. n., Tetramorium andohahela sp. n., Tetramorium andrei Forel, Tetramorium electrum Bolton, Tetramorium elf sp. n., Tetramorium isectum Bolton, Tetramorium isoelectrum sp. n., Tetramorium nify sp. n., and Tetramorium voasary sp. n. The name Tetramorium robustior Forel is proposed as junior synonym of T. andrei. The most species-poor is the T. jedi species complex with just the three species Tetramorium avaratra sp. n., Tetramorium jedisp. n., and Tetramorium pleganon Bolton. The T. noeli species complex holds four species: Tetramorium aherni sp. n., Tetramorium ambanizana sp. n., Tetramorium noeli sp. n., and Tetramorium singletonae sp. n. The T. smaug species complex includes the six species: Tetramorium adamsi sp. n., Tetramorium marojejy sp. n., Tetramorium latreillei Forel, Tetramorium nazgul sp. n., Tetramorium sabatra sp. n., and Tetramorium smaug sp. n. Furthermore, lectotypes and paralectotypes are designated for T. andrei and T. latreillei. Both species groups are fully revised with illustrated identification keys to species level. All descriptions/re-descriptions are illustrated with high-quality multifocused montage images, and distribution maps are provided for all treated species. In addition, the taxonomic validity, species composition, and biogeography of the entire T. tortuosum species group is discussed on a global basis.