(syn. Chelictinia Ϯ African Swallow-tailed Kite C. riocourii) L. nauclerus sailing-master, commander < Gr. ναυκληρος nauklēros captain < ναυς naus, νεως neōs ship; "NAUCLERUS. ... Nauclerus is distinguished from the true Milvus by the greater developement of the character of the forked tail; by the relative proportions of the wing feathers, the fourth being the longest in Milvus; and by the reticulation of the acrotarsia, those of Milvus being covered with even scales or scutellated. ... In consequence of these characters N. Riocourii comes most nearly to the group of Elanus, while N. furcatus shows an approximation to the true Milvus" (Vigors 1825).