Marsh Antwren

The marsh antwren (Formicivora acutirostris) is an insectivorous bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is endemic to southeastern Brazil. == Taxonomy and systematics == The South American Classification Committee of the American Ornithological Society (SACC), the International Ornithological Committee (IOC), and the Clements taxonomy recognize two subspecies of marsh antwren, the nominate F. a. acutirostris (Bornschein, Reinert & Teixera, 1995) and F. a. paludicola (Buzzetti et al., 2013). The marsh antwren's taxonomy has a tortuous history and in early 2024 remains unsettled. The species was first described in 1995 as Stymphalornis acutirostris. A subsequent molecular phylogenetic study showed that it belongs in genus Formicivora and by the end of 2021 worldwide taxonomic systems had made the change. Stymphalornis acutirostris was given the English name "marsh antwren" in 2003. The subspecies F. a. paludicola was discovered near São Paulo and described in 2013 as a new species in genus Formicivora. The authors coined the English name "São Paulo Marsh Antwren" for it, and retained the simple "marsh wren" for acutirostris. Confusingly, several authors then called the new species the "São Paulo Antwren" and acutirostris the Parana antwren. Others also called acutirostris the "Parana antwren" but used…