By 151 hpf, the pharyngeal skeleton includes Meckel’s (Mk), palatoquadrate (pq), basihyal (bh), ceratohyal (ch), interhyal (ih), hyosymplectic (hs), ceratobranchial (cb), copula 1, and hypobranchial cartilages. Alizarin red staining indicates the maxilla (mx), dentary (d), retroarticular (ra), entopterygoid (en), ceratohyal bone (chb), branchiostegal ray 3 (bsr3), opercle (op), and hyomandibula (hm) bones, as well as the appearance of the branchiostegal ray 2 (bsr2) bone, derived from the second pharyngeal arch.