Dear colleagues I am very pleased to announce a new paper - reporting a Miocene breeding site of an extinct baleen whale *Parietobalaena yamaokai*. Tsai, C.-H. 2017. A Miocene breeding ground of an extinct baleen whale (Cetacea: Mysticeti). *PeerJ *5:e3711 doi:10.7717/peerj.3711 Abstract Locating breeding sites is definitely a key to understanding the ecological requirements and maintaining the sustainability of populations/species. Here I re-examined published specimens of an extinct baleen whale, *Parietobalaena yamaokai*, from the lower part of Itahashi Formation (16.1–15.6 Ma, Middle Miocene) in Shobara, Hiroshima, Japan. A critical and previously unnoticed feature, the open suture between the supraoccipital and exoccipital, in one specimen indicates the preservation of a very young individual–under six months old and even close to a new-born calf. Given the occurrence of a new-born whale and relatively abundant assemblage of *Parietobalaena yamaokai*, I propose a previously hidden and unknown breeding ground for the extinct baleen whale, *P. yamaokai*, in the Middle Miocene of Shobara (16.1–15.6 Ma), Hiroshima. Discovery of paleo-breeding sites of extinct populations/species should further help us to understand biological extinctions from a long-term perspective as conservation paleobiology aims to offer new insights into policy making for conserving endangered populations/species. The paper could be freely downloaded here: https://peerj.com/articles/3711/ or, email me at: craniata@gmail.com; cheng-hsiu.tsai@otago.ac.nz Regards Tsai -- 蔡政修（Cheng-Hsiu Tsai さい まさのぶ) JSPS Postdoctoral Research Fellow (JSPS: Japan Society for the Promotion of Science 日本學術振興會) Department of Geology and Paleontology, National Museum of Nature and Science (Tsukuba Research Center) 4-1-1 Amakubo, Tsukuba-shi, Ibaraki 305-0005, Japan Email: cheng-hsiu.tsai@otago.ac.nz; craniata@gmail.com