Epiblast lumenogenesis is not a mammalian-specific trait (opens in new tab)

Epiblast lumenogenesis is a hallmark of mammalian embryogenesis, and crucial for the subsequent processes of anterior-posterior patterning and gastrulation. Based on avian model-organisms, reptile epiblasts are thought to form a monolayered flat disc to undergo these developmental events. Here, we report that the squamate, veiled chameleon (Chameleo calyptratus), exhibits epiblast lumenogenesis prior to anterior-posterior patterning. Using SEM, immunofluorescence, and histology techniques, we...