(syn. Crypturellus Ϯ Cinereous Tinamou C. cinereus) Gr. κρυπτος kruptos hidden < κρυπτω kruptō to conceal; ουρα oura tail; ορνις ornis, ορνιθος ornithos bird; "The generic name Crypturus as originally proposed by Illiger (Prodromus System. Mamm. et Avium, 1811, after April, p. 244) included two species - Tetrao cinereus Gmelin and Tetrao major Gmelin. ... However, as may be seen by reference to the introduction of Illiger's work ... the name Crypturus, along with a number of others, chiefly mammal names, must be regarded as merely substitutes for older names that Illiger for one reason or another intended to reject. ... The name Crypturus ... being a substitute and therefore an absolute synonym of Tinamus Latham, must likewise be rejected, and another name be sought for the group to which it has commonly been applied. ... since apparently there are no available synonyms, a new name must be provided for Crypturus Auct. nec Illiger. We propose, therefore, to call the group Crypturornis,1 nom. nov., with Tetrao cinereus Gmelin as type. ... 1 κρυπτος, occultus, ουρα, cauda, ορνις, avis" (Oberholser 1922).