types:
Pygopus,
genus Pygopus
type genus of the Pygopodidae; snake-shaped pleurodont lizard with no forelimbs and only rudimentary hind limbs
Xenosaurus,
genus Xenosaurus
type and sole genus of Xenosauridae: slender-bodied Mexican lizards having the upper surface covered with tiny granules and tubercles
genus Mononychus
authorities disagree over whether to classify the genus as bird or dinosaur