SOUND GENERATING STRUCTURES OF THE HUMPBACK DOLPHIN Sousa plumbea (CUVIER, 1829) AND THE DIRECTIONALITY IN DOLPHIN SOUNDS Guilherme Frainer 1, 2, 4* , Stephanie Plön 3 , Nathalia B. Serpa 1, 2 , Ignacio B. Moreno 1, 2 , Stefan Huggenberger 4 1 Programa de Pós-Graduação em Biologia Animal, Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, 91540-000, Porto Alegre, Brazil 2 Centro de Estudos Costeiros, Limnológicos e Marinhos (CECLIMAR/UFRGS), 95625-000, Imbé, Brazil 3 African Earth Observation Network (AEON) -Earth Stewardship Science Research Institute (ESSRI), Nelson Mandela University, 6031, Port Elizabeth, South Africa 4 Department II of Anatomy, University of Cologne, 50924 Cologne, Germany *Corresponding author: gui.frainer@gmail.com / Phone: 55 51 33081267 Running title: The epicranial complex of the humpback dolphin Grant sponsor: CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico); Grant number: 201709/2015-5. Grant sponsor: Capes (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). Grant sponsor: Society for Marine Mammalogy. Grant Sponsor: Cetacean Society International. This article is protected by copyright. All rights reserved Accepted Article Thi   s article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/ar.23981