Phylogenetic studies of nuclear and mitochondrial DNA after that date led to reassessment of several genera and in 2017 the wrenthrush was moved to its own family.

The exact placement of that family is still not firmly settled, but most taxonomic systems agree that it is closely related to the spindalises (Spindalidae), Cuban warblers (Teretistridae), and several other small Caribbean families, and more distantly related to New World sparrows (Passerellidae) and New World blackbirds (Icteridae).

[5] The wrenthrush's genus name commemorates José Castulo Zeledón, a Costa Rican ornithologist.

[6] The wrenthrush is found from the Cordillera de Guanacaste in northern Costa Rica discontinuously through that country into western Panama's Chiriquí and Veraguas provinces.

It has short rounded wings and a small keel to which flight muscles attach, and there was early speculation that it is evolving towards flightlessness.

[6][7] The wrenthrush forages by hopping among branches and along the ground searching for arthropods, especially spiders and Lepidoptera larvae.

It mostly forages in dense vegetation, though it occasionally works the edges of it and also hunts as high as 10 m (30 ft) above the ground in vines and epiphytes.

Their primary song is described as "ssee-del-deet with emphasis on the ending, deet", and it may be sung in a series for several minutes.