How do embryonic turtles process yolk? Evidence from the Snapping Turtle, Chelydra serpentina (Chelydridae)

In this study, we used scanning electron microscopy to determine which of these developmental patterns (if either) occurs in a representative chelonian, the North American Snapping Turtle (Chelydra serpentina (Linnaeus, 1758)). Our observations reveal that yolk-filled endodermal cells progressively fill the yolk sac cavity. These cells become organized around anastomosing blood vessels, forming elongated strands that are morphologically well suited for yolk digestion and vascular transport of nutrients. This developmental pattern shares features with that of squamates, but it differs markedly from that of birds. These observations indicate that mechanisms of yolk processing in lizards and snakes have an evolutionary history that pre-dates the squamate clade.
Source: Canadian Journal of Zoology - Category: Zoology Authors: Source Type: research