Abstract
Madagascar, one of the top megadiversity regions, hosts one of the highest numbers of endemic and threatened organisms on earth. One of the most spectacular examples of ant radiation on the island has occurred in the hyperdiverse genus Pheidole. To this date, there are 117 described Madagascan Pheidole divided into 16 species-groups, and 97% of them are endemic to the island. Only two of these species-groups contain widely distributed invasive species in addition to native, endemic taxa: megacephala, and fervens species-groups. Here we revise the fervens species-group and discuss updated distribution records of its introduced members on Madagascar. We recognize six species belonging to this group, including five new to science: Pheidole ampangabe sp. nov., P. arivo sp. nov., P. comosa sp. nov., P. indica Mayr, P. mamirapiratra sp. nov., and P. mena sp. nov. Detailed descriptions are supplemented with measurements, diagnoses, identification key, high-resolution images for major and minor worker, and comments on distribution and biology.