Family Typical Antbirds (Thamnophilidae)

Critically Endangered

Rio de Janeiro Antwren (Myrmotherula fluminensis)

Following the taxonomy applied to HBW Alive, derived from the HBW and BirdLife International Illustrated Checklist of the Birds of the World, this taxon is now lumped within Silvery-flanked Antwren (Myrmotherula luctuosa).


French: Myrmidon de Rio de Janeiro German: Rio de Janeiro-Ameisenschlüpfer Spanish: Hormiguerito Carioca

Myrmotherula fluminensis


, 1988,

Santo Aleixo, Rio de Janeiro, Brazil


Taxonomic validity questioned by various authors; was initially thought by some to be a hybrid between M. unicolor and race luctuosa of M. axillaris, and later considered possibly a variant of latter; moreover, some uncertainty over whether recent observations refer to same taxon as original type specimen. More research, including thorough analysis of recent tape recordings, is needed in order to determine its true taxonomic status. All mentioned taxa are often grouped with M. schisticolor, M. sunensis, M. minor, M. iheringi, M. behni, M. grisea, M. snowi, M. longipennis, M. urosticta and M. menetriesii as the “grey antwren assemblage”, although this grouping possibly not monophyletic. Monotypic.


C Rio de Janeiro, in SE Brazil.

Descriptive notes

c. 10 cm; 9 g. Male is grey, wings darker, throat and breast down to central belly black; wing-coverts black, broadly tipped white; underwing-coverts white; whitish eyering... read more


Nothing known; recorded vocalizations purported to be of this species considered very similar, if... read more


Little known. Single specimen was collected in a partially isolated and highly disturbed woodlot at... read more

Food and feeding

Almost nothing known. Stomach of sole specimen contained remains of arthropods. Mainly seen feeding in mixed-species flocks, usually within... read more


Nothing known.


Nothing known; specimen was obtained from a lowland site that had been studied for 7 years,... read more

Status and conservation

  CRITICALLY ENDANGERED. Restricted-range species: present in Atlantic Forest Lowlands EBA. Known from a single specimen taken near Santo Aleixo, Majé in... read more

Recommended citation

Zimmer, K., Isler, M.L. & Sharpe, C.J. (2019). Rio de Janeiro Antwren (Myrmotherula fluminensis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 22 April 2019).