The Helodermatidae or beaded lizards are a small family of lizards endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

today, but formerly more widespread in the ancient past. Traditionally, the Gila monster and the Mexican beaded lizard were the only species recognized, although the latter has recently been split into several species. While the fossil record of this family may date back to as far as the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

with genera such as '' Primaderma'' and '' Paraderma'' of North America, the oldest definitive members of the Helodermatidae date to the

Early Oligocene The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/ Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chattian ...

, with ''Lowesaurus matthewi'' from North America (Nebraska) and ''Euheloderma gallicum'' from

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

(France).

References

{{Reflist Lizard families Taxa named by John Edward Gray