(syn. Rhaphidura Ϯ Sabine's Spine-tail Swift R. sabini) L. alter, altera another < comp. alius other; genus Apus Scopoli, 1777, swift; "The third, C. sabini, is blue-black above, the upper tail-coverts white and long, the tail long and square with short projecting spines; the under-surface has the throat dark, the abdomen light: the feet are stout for the size of the bird in this group. It does not correlate with the preceding, as the tail is more than one-third the length of the wing. I therefore propose the new name ALTERAPUS with type Alterapus sabini (Gray)." (Mathews 1918) (see Neafrapus and Telacanthura).