"Unearthing the Origins: Fossil Evidence Points to Pharyngeal Source of Vertebrate Pectoral Girdle"
Fossil evidence from the braincase of an Early Devonian placoderm fish suggests a pharyngeal basis for the origin of the vertebrate shoulder girdle. The findings support the archipterygium hypothesis, which proposes that fins and girdles evolved from an ancestral gill arch. The study combines computed tomography scanning with comparative anatomy of placoderms and jawless outgroups to locate the origin of the pectoral girdle on the sixth branchial arch. These findings provide a new framework for understanding the evolution of the pectoral girdle and help reconcile the archipterygium hypothesis with the ventrolateral fin-fold model.