2025-02-102025-02-102016-03MORAIS, Raquel Rezende de et al. Ocorrência e autoecologia de Acanthoceras zachariasii (Brun) Simonsen (Chaetocerales, Coscinodiscophyceae) na região centro-norte do Brasil. Hoehnea, São Paulo, v. 43, n. 1, p. 27-37, 2016. DOI: 10.1590/2236-8906-21/2015. Disponível em: https://www.scielo.br/j/hoehnea/a/RHbpq5PC5vXHsG5Y6Gfc83g/?lang=pt. Acesso em: 11 nov. 2024.0073-2877e- 2236-8906http://repositorio.bc.ufg.br//handle/ri/26647In this study we presented the structural and ultrastructural characterization ofAcanthoceras zachariasii (Brun) Simonsen, as well as its geographical distribution in the Amazon River Basin and Tocantins-Araguaia River Basin, Brazil, and provided the lectotypification of the taxon. We analyzed 454 phytoplanktonic samples, but the occurrence of A. zachariasiiwas recorded in only 14 of them. Of the total samples collected along the two basins, A. zachariasii was recorded only in 3.08%, which demonstrates the rarity of this taxon. This species was registered in lentic environments, with mesotrophic to eutrophic conditions, and pH varying from slightly acid to alkaline.porAcesso Abertohttp://creativecommons.org/licenses/by-nc-nd/4.0/Amazon River BasinTocantins-Araguaia River BasinAttheya zachariasiiAcanthoceras magdeburgenseLectotypificationBacia AmazônicaBacia do Tocantins-AraguaiaLectotipificaçãoArtigo10.1590/2236-8906-21/2015