A conserved pattern of development and arrangement of the extraembryonic membranes is well supported within Squamata; however, the interaction of the extraembryonic membranes and its external environment varies with reproductive mode (oviparous/viviparous) and with the pattern of embryonic nutrition (lecithotrophy/placentotrophy). Because those variations can be related to structural and functional changes in the developmental timing of the extraembryonic membranes, we analyzed heterochrony on the ontogenetic sequences of
