Ossification patterns of the carpus and tarsus in salamanders and impacts of preaxial dominance on the fin-to-limb transition

• DOI: 10.1126/sciadv.abq7669
• Publication Date: 2022-10-14T18:00:45Z
• Authors: Jia Jia; Jason S. Anderson; Jian-Ping Jiang; Wenhao Wu; Neil H. Shubin; Ke-Qin Gao
• Keywords: Tetrapod (structure); Neoteny

Early limb skeletogenesis in salamanders is characterized by preaxial elements, digits I and II forming earlier than their postaxial counterparts (digits III to V), a phenomenon known as dominance, whereas amniotes anurans, these developmental sequences are reversed. This pattern characterizes the late of zeugopodium anamniote tetrapods but remains unknown carpals/tarsals. To correct this gap knowledge, we investigate ossification patterns carpals/tarsals six salamander families/clades based on micro-computed tomography scans. We found that dominance seen distal several clades diverse early tetrapods, such temnospondyls amniotes. distribution suggests primitive tetrapods. Our results demonstrate developmentally evolutionarily independent autopodium, facilitates stabilization number during fin-to-limb transition digit reduction