The name of the genus is derived from the
Latin regulus, a diminutive of
rex, "a king", and refers to the characteristic orange or yellow crests of adult kinglets. Several forms have only recently had their status clarified. The
Madeira firecrest was formerly considered to be a subspecies,
R. i. madeirensis, of the
common firecrest R. ignicapillus. A
phylogenetic analysis based on the
cytochrome b gene showed that the Madeiran form is distinct at the species level from the firecrest
nominate subspecies R. i. ignicapillus. Cytochrome
b gene divergence between the Madeira firecrest and the European bird is 8.5%, comparable with the divergence level between other recognised
Regulus species, such as the 9% between the
goldcrest and the
golden-crowned kinglet. The split was accepted by the
Association of European Rarities Committees (AERC) in 2003. The
golden-crowned kinglet is similar in appearance to the common firecrest and has been considered to be its New World equivalent, but it is actually closer to the
goldcrest. and have been sometimes treated either as a subspecies of the common firecrest or as a different
Regulus species altogether. They were sometimes called the
Tenerife goldcrest, no matter which of the islands they lived on; however, a 2006 study of the vocalisations of these birds indicate that they actually comprise two subspecies of the Goldcrest that are separable on voice;
R. r. teneriffae occurring on Tenerife and the newly described subspecies,
R. r. ellenthalerae, occurring on the smaller islands of La Palma and El Hierro. The three goldcrest
taxa on the
Azores,
Santa Maria goldcrest,
Sao Miguel goldcrest and
Western Azores goldcrest, represent recent colonisations from Europe, and are best treated as subspecies. The relationships of the
flamecrest or Taiwan firecrest (
Regulus goodfellowi) of Taiwan have also been a source of much debate. It is sometimes viewed as a race of firecrest, but its territorial song resembles those of the
Himalayan races of goldcrest, and genetic data show that it is the closest relative of that species, and, despite its alternative name, only distantly related to the firecrest. The flamecrest diverged from the Goldcrest 3.0–3.1
mya (million years ago). == Species ==