Multi-character taxonomic review, systematics, and biogeography of the Blackcapped / Tawny-bellied Screech Owl (Megascops atricapilla-M. watsonii) complex (Aves: Strigidae) Author Dantas, Sidnei M. 0000-0002-2281-0819 Zoology Graduate Program, Universidade Federal do Pará / Museu Paraense Emilio Goeldi, Belém-PA, Brazil. smdantas @ yahoo. com; https: // orcid. org / 0000 - 0002 - 2281 - 0819 & Department of Zoology, Museu Paraense Emílio Goeldi, Belém-PA, Brazil. smdantas@yahoo.com Author Weckstein, Jason D. 0000-0003-3850-1196 Department of Ornithology, Academy of Natural Sciences of Drexel University, 1900 Benjamin Franklin Parkway, Philadelphia, PA, USA 19096. tac 327 @ drexel. edu; https: // orcid. org / 0000 - 0003 - 3850 - 1196 & Department of Biodiversity, Earth and Environmental Science, Drexel University, 1900 Benjamin Franklin Parkway, Philadelphia, PA, USA 19096. jason. d. weckstein @ drexel. edu; https: // orcid. org / 0000 - 0001 - 7941 - 5724 tac327@drexel.edu Author Bates, John 0000-0002-5809-5941 Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive Chicago, IL, USA 60605. jbates @ fieldmuseum. org; https: // orcid. org / 0000 - 0002 - 5809 - 5941 jbates@fieldmuseum.org Author Oliveira, Joiciane N. Department of Zoology, Museu Paraense Emílio Goeldi, Belém-PA, Brazil. & Graduate Program in Environmental Biology, Universidade Federal do Pará, Bragança-PA, Brazil. Author Catanach, Therese A. 0000-0001-7941-5724 Department of Biodiversity, Earth and Environmental Science, Drexel University, 1900 Benjamin Franklin Parkway, Philadelphia, PA, USA 19096. jason. d. weckstein @ drexel. edu; https: // orcid. org / 0000 - 0001 - 7941 - 5724 jason.d.weckstein@drexel.edu Author Aleixo, Alexandre Department of Zoology, Museu Paraense Emílio Goeldi, Belém-PA, Brazil. & Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland. text Zootaxa 2021 2021-03-26 4949 3 401 444 journal article 7573 10.11646/zootaxa.4949.3.1 1450e926-933d-4ae8-bc64-a8df7b295697 1175-5326 4640330 2CAB47C9-2109-45DA-8F02-50D74D593DF2 Megascops usta ( Sclater, 1858 ) Variable Screech-Owl corujinha-relógio (Portuguese) Scops usta Sclater, 1858 ( type not examined). Pisorhina watsonii (Cassin, 1848) : Hellmayr (1907) . Otus watsonii (Cassin, 1848) : Hellmayr (1910) . Pisorhina usta ( Sclater, 1858 ) : Snethlage (1914) . Otus watsonii usta ( Sclater, 1858 ) : Chapman (1928) ; Peters (1940) ; Hekstra (1982) ; Marks et al. 1999 ; Weick (2006; part: specimens in southernmost Venezuela and Amazonian Colombia , Ecuador , Peru , Bolivia , and Brazil between the western banks of the Negro and the lower Tapajós and upper Xingu rivers). Otus atricapillus morelius Hekstra, 1982 : Browning (1989) ; holotype at AMNH examined . Otus atricapillus inambarii Hekstra, 1982 : Browning (1989) ; holotype at FMNH examined . Otus atricapillus fulvescens Hekstra, 1982 : Browning (1989) ; holotype at AMNH examined . Megascops usta ( Sclater, 1858 ) : König et al. (1999) ; König & Weick (2008 ; part: specimens in southernmost Venezuela and Amazonian Colombia , Ecuador , Peru , Bolivia , and Brazil between the western banks of the Negro and the lower Tapajós and upper Xingu rivers). Megascops watsonii usta ( Sclater, 1858 ) : Dickinson & Remsen (2013) ; Clements et al. (2019) ; Gill et al. (2020 ; part: populations in southernmost Venezuela and Amazonian Colombia , Ecuador , Peru , Bolivia , and Brazil between the western banks of the Negro and the lower Tapajós and upper Xingu rivers). With type locality referred as Tefé, Amazonas, Brazil ( Sclater, 1858 ), and corresponding to specimens in Clade B, M. usta is distributed over a wide geographic area in Amazonia, ranging from west of the Branco-Negro rivers throughout the Imerí, Napo, Inambari, Madeira and upper stretches of the Tapajos and Xingu AOEs. Strong statistical support for reciprocal monophyly, high degree of coalescence, and high uncorrected pairwise p-distances ranging from 2.1% ( M. ater ) to 6.4% ( M. watsonii ) differentiates this taxon from others in the Megascops atricapilla-M. watsonii complex. Morphologically variable with multiple morphs, mainly brown or red, but also gray, and not safely distinguishable solely based on morphology from the other species in the complex. There is geographical variation in the frequency of different morphs among populations. Apparently does not include morphs as dark in color as those found in M. watsonii and M. ater . Vocally distinct from M. watsonii , M. stangiae and M. atricapilla by on average slower-paced longsongs and shortsongs ( Fig. 9 ; Tables 6 , 8 , and 10).