Formicariidae
Formicariidae is a family of smallish passerine birds of subtropical and tropical Central and South America known as formicariids. They are between in length, and are related to the antbirds, Thamnophilidae, and gnateaters, Conopophagidae. This family contains probably some 12 species in two fairly small genera.
These are forest birds that tend to feed on insects at or near the ground. Most are drab in appearance with shades of brown, black, and white being their dominant tones. Compared to other birds that specialize in following ants, this family is the most tied to the ground. The long, powerful legs and an essentially vestigial tail aid this lifestyle.
They lay two or three eggs in a nest in a tree, both sexes incubating.
Systematics
The antthrushes in the genera Formicarius and Chamaeza are similar in appearance to small rails. Their sexes are alike in plumage, and they walk like starlings. The thrush part of the name refers only to the similarity in size to true thrushes, not to an evolutionary relationship.Recent research indicates that the Formicariidae as previously delimited are highly paraphyletic, judging from comparison of several mt and nDNA sequences. The aberrant bar-bellied "antpittas" of the genus Pittasoma, which were formerly placed here, belong to the gnateater family ; as the gnateaters proper, they are sexually dichromatic. In addition, the true antpittas formerly placed in this family are now found in their own family, the Grallariidae. On the other hand, at least a large proportion of the Rhinocryptidae, including the type genus Rhinocrypta, seem to be closer to the antthrushes, but are still considered a distinct family.
Very little molecular data is currently available for rhinocryptids, which are moreover rather non-diagnostic morphologically. As relationships with related groups such as ovenbirds have not been fully resolved, it is certain that the systematics of the group will be revised soon, but it is not clear how exactly the new systematic lineup will be. On the other hand, morphological, behavioral and molecular analyses of the true antpittas agree astoundingly well as regards their internal systematics, considering the high amount of lifestyle-related homoplasies in the birds discussed here.
Recent taxonomic favor has moved three major lineages – antthrushes, tapaculos and allies, and antpittas into separate families.
Antthrushes
Typical antthrushes - tribe Formicariini/subfamily Formicariinae| Image | Genus | Living species |
| Formicarius Boddaert, 1783 |
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| Chamaeza Vigors, 1825 |