Taxonomy
The species-limits within this genus is among the most complex matters in Neotropical ornithology. They are highly cryptic, and identification using visual features often is impossible. Vocal and biochemical data is typically needed to clarify the taxonomic status of the various populations. Several new species have been described in recent years (e.g. S. stilesi and S. rodriguezi from Colombia). The taxonomic status of many of the Andean species was resolved by Krabbe & Schulenberg (1997) who split a number of species and described three new ones. The confusing situation is perhaps best illustrated by the fact that only 10 species were recognized in this genus in 1970 (Krabbe & Schulenberg, 2003), while the figure now is more than four times as high. Additionally, still undescribed species are known to exist (e.g. the "Apurimac Tapaculo" and "Millpo Tapaculo"; both from Peru), while some species as currently defined actually may include several species (e.g. the southern population of the Large-footed Tapaculo may represent an undescribed species). Donegan & Avendano recently reviewed the Colombian and Venezuelan species, formally describing one new subspecies and providing details of a further three undescribed species or subspecies to be described in future publications.
The Brazilian taxa are similarly complex with several recently described species and considerable confusion surrounding the use of the scientific name Scytalopus speluncae.
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