Here’s New Scientist on reptiles that nourish their young via a placenta:
All live-bearing reptiles have a basic placenta, but unlike its mammalian counterpart the embryo doesn’t get much food that way. It can’t: although it nestles up against the oviduct wall, the embryo remains inside a remnant of eggshell that acts as a barrier. Instead, it is nourished by a large yolk.
A very few reptiles, including T. ivensii, break this rule. Their eggs are small, with little yolk, so they must get lots of food from their mothers via the placenta. But only T. ivensii allows the embryo to implant itself in the oviduct wall. “It’s unprecedented,” Blackburn says.
Not sure if that qualifies as a placenta, but it sure raises some questions.