The eastern black-handed tamarin (''Saguinus ursulus'') is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

tamarin The tamarins are squirrel-sized New World monkeys from the family Callitrichidae in the genus ''Saguinus''. They are the first offshoot in the Callitrichidae tree, and therefore are the sister group of a clade formed by the lion tamarins, Go ...

endemic to

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Taxonomy

''Saguinus ursulus'' was described in 1807 by the German zoologist

Johann Centurius Hoffmannsegg Johann Centurius Hoffmann Graf von Hoffmannsegg (23 August 1766 – 13 December 1849) was a German botanist, entomologist and ornithologist. Hoffmannsegg was born at Rammenau and studied at Leipzig and Göttingen. He travelled through Euro ...

. It was later synonymised, first with '' S. midas'' and then with '' S. niger''. In 2013, ''S. ursulus'' was revalidated based on differences in coat color and morphological divergences, which were corroborated by molecular data. Based on mitochondrial DNA analysis, ''Saguinus niger'', the black-handed tamarin, was split into two species: '' S. niger'', the western black-handed tamarin, and ''S. ursulus'', the eastern black-handed tamarin. The

Tocantins River The Tocantins River ( pt, Rio Tocantins, link=no , , Parkatêjê: ''Pyti'' ɨˈti is a river in Brazil, the central fluvial artery of the country. In the Tupi language, its name means "toucan's beak" (''Tukã'' for "toucan" and ''Ti'' for "beak" ...

which divided the range was found to constitute an effective

gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalen ...

barrier. As a consequence of the genetic divergence, as well as minor differences in pelage color, the population east of the Tocantins River was recognised as a separate species.

References

Eastern black-handed tamarin Mammals of Brazil Endemic fauna of Brazil Eastern black-handed tamarin Taxa named by Johann Centurius Hoffmannsegg {{newworld-monkey-stub