Tapaculos are small to medium-sized birds, with a total length ranging from 10–24 cm. These are terrestrial species that fly only poorly on their short wings. They have strong legs, well-suited to their habitat of grassland or forest undergrowth. The tail is cocked and pointed towards the head, and the name tapaculo possibly derives from Spanish for "cover your behind". Another possible explanation is that it originates from the Chilean name for the white-throated tapaculo, simply tapaculo, which is an onomatopoeic reference to its commonly heard song. While the majority of the family are small blackish or brown birds there are some larger and more colourful species. All tapaculos are skulking birds that frequently stay low in dense vegetation, even the larger, colorful species, and this renders them difficult to see. They are best located and - in the case of Scytalopus spp. - identified by their vocalisations. They feed on insects, seeds and other soft plant material with their pointed bills, and will scratch on the ground like a pheasant. Most species lay two or three white eggs in a covered location, whether it be a burrow, a hole in a tree, or a domed nest.
The tapaculos were traditionally placed in a distinct family Rhinocryptidae; more recent research indicates that according to analysis of mt and nDNAsequencedata, the tapaculos might be better merged into the Formicariidae as tribeRhinocryptini, as they are closer to the antthrushes than either is to the true antpittas. Alternatively, the latter might be raised to family status. In this case, it would be possible to maintain the tapaculos as a separate family too, but it would seem altogether more warranted to consider them a subfamily of the Formicariinae sensu stricto, which would be called Rhinocryptinae. Whether this latter approach, the placement as a tribe in a tapaculo-antthrush Formicariinae subfamily, or maintenance as a separate family is to be preferred depends on whether the true antpittas are closer to the tapaculos and true antbirds, or rather to the Pittasoma "gnatthrushes" and other gnateaters and the true antbirds. There are some, albeit very tentative, indications that the latter may indeed be the case, which would be reflected in the placement of the tapaculos as subfamily Rhinocryptinae, with the Formicariinae being restricted to the true antthrushes. Today, the tapaculos continue in the Rhinocryptidae until the systematics can be further defined. Apparently not all tapaculo genera would have to be moved to the formicariids. As the type genusRhinocrypta certainly would, any distinct genera would need a new family name. An alternative family name Pteroptochidae, has been used historically.
Taxonomy of ''Scytalopus''
The species-limits within the genus Scytalopus is among the most complex matters in Neotropicalornithology. 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. The Brazilian taxa are similarly complex with several recently described species and considerable confusion surrounding the use of the scientific nameScytalopus speluncae. Additionally, still undescribed species are known to exist, while some species as currently defined actually may include several species. The confusing situation is perhaps best illustrated by the fact that only ten species were recognized in this genus in 1970, while the figure now is more than four times as high.
