(Ptiliogonatidae; Ϯ Grey Silky-flycatcher P. cinereus) Gr. πτιλον ptilon  feather; γονυ gonu, γονατος gonatos  knee; "G. PTILIOGONYS. Swains. in Zool. Journ. No. 10.   26. Ptiliogonys cinereus.  Cinereous; chin and middle of the lateral tail feathers white; under tail covers yellow; wings and tail shining black.  Table land of Mexico. Real del Monte" (Swainson 1827); “There has been much diversity among writers in the spelling of the name of this genus, Mr Swainson, its author, having himself written it very differently. His first rendering of the name, however—Ptilogonys—is more nearly correct than the subsequent ones, as compounded of ptilon and gonu, or feathered knee, in allusion to the tuft of cottony feathers on the tibiae” (Baird 1866); "Ptilogonys Swainson, 1824, Cat. Exhib. called Modern Mexico, App., p. 42. Type, by monotypy, Ptilogonys cinereus Swainson.    Ptiliogonys Swainson, 1827, Phil. Mag., n. s., 1, fasc. 5, p. 368. Type, by monotypy, Ptiliogonys cinereus Swainson.   ...   2 Not seen. Sherborn (Ind. Anim., Sect. 2, 1922, p. xxxiv, cxx) states that he never saw the last (undated) appendix on page 4 of which Swainson (Zool. Illustr., ser. 2, 2, 1831, pl. 62) says the original description appears. As far as can be ascertained no one has been able to find it. The accustomed spelling of recent years is retained here." (Greenway in Peters IX 1960). However, Gregory & Dickinson 2012, concluded that, “Ptiliogonys is not an original spelling that requires correction, the spelling Ptilogonys is an incorrect subsequent spelling.”
Var. Ptiliogenys, Ptilogonys, Ptiliogonatus, Ptilogonatus, Ptiliosmatus, Pliliogonys.
Synon. Sphenotelus.

Search for more names on the Key to Scientific Names in Ornithology by James A. Jobling.
Recommended citation
Jobling, J. A. (2019). Key to Scientific Names in Ornithology. In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2019). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 24 January 2019).