“…Emerging consensuses include the wholesale movement of acanthodians on to the chondrichthyan stem (Brazeau, 2009 ; Davis et al, 2012 ; Dearden et al, 2019 ; Maisey et al, 2017 ; Miller et al, 2003 ; Zhu et al, 2013 ), and, more contentiously, recognition of numerous Paleozoic clades as stem holocephalans (Coates et al, 2017 , 2018 ; Dearden et al, 2019 ; Frey et al, 2020a , b ). With this change has come increasing recognition that total group Chondrichthyes (Andreev et al 2022 ; Coates et al, 2018 ), and thus all crown gnathostomes, originated at least as far back as the early Silurian (Andreev et al, 2022 ; Zhu et al, 2022 ). Among the stem holocephalans, the Symmoriiformes are an important group, comprising a series of bizarre species, several of which bear unusual fin spines (Coates & Sequeira, 1998 , 2001 ; Lund, 1985 , 1986 ; Williams, 1985 ; Zangerl, 1990 ; Zangerl & Case, 1976 ).…”