South-eastern Brazil (extreme south-eastern Minas Gerais and southern Rio de Janeiro to northern Rio Grande do Sul) and north-eastern Argentina (Misiones).
 
Population
Estimated population is unknown (2010) and decreasing.
Status NT
Habitat destruction and degradation through conversion to agriculture is the main threat.
For more information see BirdLife International Species Factsheet.
Voice
The song is a high pitched descending trill. Also various high pitched calls.
Araucaria Tit-Spinetail (Leptasthenura setaria) [XC224997]
by Kassius Santos from Aparados da Serra, Rio Grande do Sul, Brazil (song)
Araucaria Tit-Spinetail (Leptasthenura setaria) [XC332923]
by Douglas Meyer from Itatiaia National Park - Agulhas Negras road, Brazil (song)
Subspecies
No subspecies.
Formerly placed in a monotypic genus Dendrophylax or Bathmidura. Differs from other members of current genus in bill and tail shapes and in details of plumage pattern.
Similar Species
Could only be confused with the sympatric Striolated Tit-Spinetail (Leptasthenura striolata) which has a streaked mantle and no crest.
References
See References.