Two new phragmotic ant species from Africa: morphology and next-generation sequencing solve a caste association problem in the genus Carebara Westwood

Phragmotic or "door head" ants have evolved independently in several ant genera across the world, but in Africa only one case has been documented until now. Carebara elmenteitae (Patrizi) is known only from a single phragmotic major worker collected from sifted leaf-litter near Lake Elmenteita in Kenya, but here we study and compare the worker castes of two species collected from Kakamega Forest, a small rainforest in Western Kenya, which were previously identified as Carebara elmenteitae (phragmotic major workers) and non-phragmotic major and minor workers of C. thoracica (Weber). Using evidence of both morphological and a next-generation sequencing analyses, we show that phragmotic and non-phragmotic workers of the two different species are actually the same and that neither name - C. elmenteitae or C. thoracica - correctly applies to them. Instead, this and another closey related species from Ivory Coast are both morphologically different from C. elmenteitae, and thus we describe them as the new species Carebara phragmotica and Carebara lilith.