(Regulidae; Ϯ Goldcrest R. regulus) Specific name Motacilla regulus Linnaeus, 1758; "Roitelets . . . Regulus" (Cuvier 1800); "Regulus Cuvier, 1800, Leçons Anatomie Comparée, 1, table 2. Type, by monotypy and tautonymy, "Roitelets" = Motacilla regulus Linnaeus" (G. Watson in Peters 1986, XI, 286); "Dans la tradition nordique, le roitelet (le plus petit des oiseaux) est le druide des oiseaux. Ce term de petit roi n'est donc pas une moquerie, il correspond à une vieille tradition celtique. Le première mention de ce mot pour désigner un oiseau remonte au début du XIIe siècle" (Cabard & Chauvet 2003). This genus formerly included the reguline leaf-warblers Phylloscopus.
Var. Regillus (L. regillus  royal, regal  < regius  royal).
Synon. Calendula, Corthylio, Ocelletus, Orchilus, Regaliolus, Rex, Senator.
● (syn. Regulus Ϯ Ruby-crowned Kinglet R. calendula) "Regulus BARTRAM, Travels through Carolina, etc., 1791, p.--  ...  Type, Motacilla calendula LINNAEUS (Present designation.)...  2 Seven species of Regulus are enumerated by Bartram in 1791, but only one is technically available as type at this date. This is "R. cristatus alter vertice rubini coloris; the ruby crown wren. (G. Edwards.)", or Motacilla calendula Linnaeus. Edwards figured and described this species from a specimen sent to him by Bartram.  ...  3 There appear to be excellent generic differences between Motacilla calendula and M. regulus, as long ago recognized by Cabanis, who, in 1853, proposed the name Corthylio for M. calendula. This genus has been recently revived by Mr. Miller (Auk, vol. 32, 1915, pp. 234-236), but from the above reference to Regulus it will be seen that Motacilla regulus is the species to be provided with a generic name." (Richmond 1917). 

Search for more names on the Key to Scientific Names in Ornithology by James A. Jobling.
Recommended citation
Jobling, J. A. (2018). Key to Scientific Names in Ornithology. In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2018). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 11 December 2018).