''Willisornis'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of insectivorous

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines are distinguished from other orders of birds by t ...

birds in the antbird family, Thamnophilidae. These small, strongly

sexually dichromatic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most anim ...

birds are native to

the Guianas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...

and

Amazon rainforest The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

, and often follow army ants.

Taxonomy

The genus ''Willisornis'' was erected by the Brazilian ornithologists Carlos Agne and José Fernando Pacheco in 2007. The genus is named after the American ornithologist

Edwin O'Neill Willis Edwin O'Neill Willis (18 January 1935 – 11 April 2015) was an American ornithologist who studied the birds of Central and South America. Biography Willis was born on 18 January 1935, the son of Andrew Nelson Willis and Verna Fleming. He was ra ...

. The common scale-backed antbird had traditionally been included in the genus ''

Hylophylax ''Hylophylax'' is a genus of bird in the family Thamnophilidae. The genus ''Hylophylax'' was erected by the American ornithologist Robert Ridgway in 1909 with the spotted antbird as the type species. It contains three species: * Spotted antbird ...

'', but is now known to belong to a different

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. The name ''Dichropogon'' was used briefly instead, but this name is preoccupied by a genus of asilid flies (''Dichropogon'' Bezzi, 1910). The two species are: *

Common scale-backed antbird The common scale-backed antbird (''Willisornis poecilinotus'') is a species of passerine bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana ...

(''Willisornis poecilonotus'') * Xingu scale-backed antbird (''Willisornis vidua'') The two species were previously considered

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organ ...

. They were split based on the differences in their vocalization.

References

Bird genera {{Thamnophilidae-stub