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Newman’s Knob-scaled Lizard

Xenosaurus newmanorum


This prehistoric-looking lizard is part of an ancient family, Xenosauridae, which diverged from all other living reptiles more than 85 million years ago.

To put this in perspective, our family, Hominidae, split from all other primates less than 20 million years ago!

Xenosaurids are unusual amongst lizards as they are viviparous, giving birth to live young, whereas most lizards lay eggs. Females are ‘pregnant’ for up to 12 months and there is evidence they provide maternal care for their offspring!

A major threat is forest conversion for coffee plantations, which is destroying their natural habitat. This species is also mistaken for the venomous Heloderma lizards, with which it is sympatric, and persecuted by local people.

This species is not known from any protected areas. Further research is required to determine the full range of this species and to understand the impact of habitat conversion on the persistence of the known populations.

  • Order: Squamata
  • Family: Xenosauridae
  • Population: Common
  • Trend: decreasing

EDGE Score

EDGE Score: 5.84 (?)
ED Score: 42.122 (?)
GE / IUCN Red List (?)
Not Evaluated Data Deficient Least Concern Near Threatened Vulnerable Endangered Critically Endangered Extinct in the Wild Extinct


This species is found in the area of Xilita in the extreme south-eastern San Luis Potosi State and from La Selva, Mexico, around 1,100-2,000 metres above sea level.

Habitat and Ecology

Individuals are found in rock crevices, within areas of highly eroded karst limestone in closed canopy tropical deciduous and oak forest, pine forest and plantations. Individuals have a relatively small home range and are largely sedentary

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