Strumigenys emmae (Emery, 1890) (Myrmicinae) new to Britain, with an updated key to the known Strumigenys of the West Palaearctic.

The ant genus Strumigenys is a hyper diverse pantropical group of specialised predatory leaf litter dwelling ants. Species richness peaks within tropics, with few species extending into the West Palaearctic realm. A significant proportion of Strumigenys species known from the West Palaearctic are non-native, spread via human commerce, and predominately establishing populations within artificially heated greenhouses. In Britain, two Strumigenys species were previously known, S. rogeri Emery, 1890 and S. perplexa (Smith, 1876). Here we add a third species, S. emmae (Emery, 1890) based upon specimens from the humid tropical biomes at the Eden Project, Cornwall (UK). A single record outlined here is noted as the earliest known record of S. emmae from Europe thus far, pre-dating previous records by four years. We provide high resolution images, measurements, and discussion on the ecology of the species. In addition, an updated key to the Strumigenys of the Europe is supplied.