... eggs and obligate placentotrophy. One major event that favored the evolution of placentation was the reduction of the eggshell. As with all oviparous reptiles, lizard embryos obtain calcium from both the eggshell and egg yolk. Therefore, the loss of the eggshell likely imposes a constraint...

...James U. Van Dyke; Steven J. Beaupre SUMMARY Viviparity and placentation have evolved from oviparity over 100 times in squamate reptiles (lizards and snakes). The independent origins of placentation have resulted in a variety of placental morphologies in different taxa, ranging from simple...

...James R. Stewart; Michael B. Thompson ABSTRACT Vitellogenesis and placental transfer both contribute substantially to embryonic nutrition in the viviparous scincid lizard Pseudemoiaentrecasteauxii . Neonatal wet mass was 396% greater than egg wet mass and neonatal dry mass was 168% greater than egg...