Cercomacra is a genus of passerine birds in the antbird family Thamnophilidae. They are insect-feeding birds that mainly inhabit tropical and subtropical forest areas of South America, extending into Central America. Cercomacra is distinguished from other bird genera by its sexual dimorphism and communication patterns. They often forage close to the ground or in low vegetation. A molecular phylogenetic study has shown that the traditional genus Cercomacra is not monophyletic but is divided into two distinct lineages: the "nigricans group", which retains the original genus name, and the "tyrannina group", now recognized as the separate genus Cercomacroides.
Taxonomy
The genus Cercomacra was introduced in 1858 by the English zoologist Philip Sclater. He listed five species in the new genus but did not specify the type. Over thirty years later in 1890 Sclater designated the type as Cercomacra caerulescens P.L. Sclater, 1858. Unfortunately, the specific epithet had been used in 1817 by the French ornithologist Louis Vieillot for a related species. In 1905 the Austrian ornithologist Carl Eduard Hellmayr designated the type species as Cercomacra brasiliana Hellmayr, 1905, the Rio de Janeiro antbird. The genus name Cercomacra combines the Ancient Greek κερκος/kerkos meaning "tail" with μακρος/makros meaning "long".
The genus is a member of the family Thamnophilidae, also called antbirds. The antbirds included in the genus Cercomacra are relatively large, have unicolored feathers and wide, flat beaks, distinguishing them from genera such as Formicivora and Pyriglena. At that time, Cercomacra was interpreted as a transitional form between these genera, while retaining sufficient structural features to support its distinction. Sclater's classification was based on wild specimens from various regions of South America, including Brazil and the upper reaches of the Amazon River.
Historically, Cercomacra was regarded as a monophyletic genus comprising twelve...
