What is "tachymarptis"

Tachymarptis is a genus of bird in the swift family, Apodidae. It contains the Alpine swift (Tachymarptis melba) of Eurasia and Africa and the mottled swift (Tachymarptis aequatorialis) of Africa. They are large swifts with relatively broad wings, a large head, a medium-length forked tail and white in the underparts. They are often included in the genus Apus but they are larger than other members of that genus, their nestlings have a different foot structure and they host different species of feather lice. A recent study of mitochondrial and nuclear markers supports the separation of Tachymarptis and Apus. The name Tachymarptis comes from Greek takhus ("fast") and marptis ("seizer").