Fossil
Taxon rank: species
Nomenclatural code: ICZN
Original publication: Boev Z. 1999 Regulus bulgaricus sp. n. — the first fossil Kinglet (Aves: Sylviidae) from the Late Pliocene of Varshets, Western Bulgaria. Historia naturalis bulgarica 10: 109–115.
Type locality: Bulgaria: ‘A ponor in a rocky hill, 6 km NNE of Varshets (43° 13′ N, 23° 17′ E)’.