The cytokine FAM3B/PANDER is an FGFR ligand that promotes posterior development in Xenopus. - Zhang F; Zhu X; Wang P; He Q; Huang H; Zheng T; Li Y; Jia H; Xu L; Zhao H; Colozza G; Tao Q; et al. (Proceedings of the National Academy of Sciences of the United States of America, 2021)