The Great Spinetail is a furnariid restricted to the upper Marañón drainage of northern Peru. It uses the understory of dry and semideciduous forest.
The crown, mantle and tail are olive-brown, and the wing is rufous-brown. It has a pale eyebrow and throat, while the grayish breast and belly are densely streaked white.
It occurs in the understory of dry and semideciduous forest in the upper Marañón drainage, the restricted range given by the account.
An extinction-risk assessment has not been added yet.