This article is protected by copyright. All rights reserved RESEARCH ARTICLE Sperm storage influences the potential for spontaneous acrosome reaction of the sperm in the newt Cynops pyrrhogaster † Running title: Spontaneous acrosome reaction in newt sperm Shinnosuke Kon 1 , Tae Sato 1 , Daisuke Endo 1 , Tomoe Takahashi 1 , Akio Takaku 1 , Yuni Nakauchi 1 , Fubito Toyama 2 , Victor Benno Meyer-Rochow 3 , Eriko Takayama-Watanabe 4,* , Akihiko Watanabe 1,* 1: Department of Biology, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560, Japan 2: Graduate School of Engineering, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan 3: Department of Biology, University of Oulu, FIN-90401 Oulu, Finland and Research Institute of Luminous Organisms, Hachijojima, Tokyo 100-1623, Japan 4: Institute of Arts and Sciences, Yamagata University, Yamagata 990-8560, Japan *Corresponding author: E. Takayama-Watanabe: ewatanab@kdw.kj.yamagata-u.ac.jp, A. Watanabe: watan@sci.kj.yamagata-u.ac.jp † This 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/mrd.22932] Additional Supporting Information may be found in the online version of this article. Received 8 August 2017; Revised 10 November 2017; Accepted 13 November 2017 Molecular Reproduction & Development This article is protected by copyright. All rights reserved DOI 10.1002/mrd.22932