Reptilia · Squamata
Xenosaurus agrenonKing & Thompson, 1968
Mountain Knob-scaled Lizard
No photograph of this species exists under a license anyone may reuse. It gets the same page regardless.
A rock-dwelling, day-active lizard from the Neotropic region, reaching 120 mm snout to vent.
Reptilia › Squamata › Xenosauridae › Xenosaurus
- Grows to
- 120mm
- greatest recorded
- Active
- Diurnal
- Lives
- Saxicolous
- Weighs up to
- 39.06g
- greatest
What is known
30 sourced facts, each taken from a named scientific dataset. How to read these.
Cited from a dataset unless a row is marked otherwise.
Standing in the world
- Still living
- Extant
The animal itself
- Limbs
- Four legs
- Venomous
- No
- Fangs
- None
- Body temperature when active · measured in the wild
- 25.5°C78 °F
- Body temp in the wild · mean, when active
- 25.4–25.6°C78–78 °F
mean body temperature of active individuals in nature
body temperature of active animals in nature
Size
- Length snout to vent · greatest recorded
- 120mm4.75 in
- Length snout to vent · adult female mean
- 106mm4.25 in
- Largest female · snout to vent
- 106mm4.25 in
- Hatchling length · snout to vent
- 45.77mm1.75 in
- Largest juvenile · snout to vent
- 46mm1.75 in
- Body mass · greatestcomputed
- 39.06g1.4 oz
max 120 mm SVL (Feldman et al. 2016)
snout-vent length; the source column mixes this with straight carapace length
computed from length by a family-level allometric equation, not weighed
How it lives
- Active
- Diurnal
- Where it lives
- Saxicolous
- Biome
- Tropical & Subtropical Coniferous Forests
- Region
- Neotropic
- Mainland or island
- Mainland
- Elevation · above sea level
- 1000–1470m
- Range size
- 24,668km²
1235 (Woolrich-Pina et al. 2020)
Breeding
- Reproduction
- Viviparous
- Average clutch
- 2.95eggs
- Eggs or young per clutch
- 1–5eggs
- Mean clutch
- 2.7–3.2eggs
1-5, mean 3.2 (Lemos-Espinal et al. 2003), 1-4, mean 2.7 (Zamora-Abrego et al. 2007), means 2.7-3.2 (Woolrich-Pina et al. 2014), means 2.7-3.2 (Zuniga-Vega et al. 2017)
Naming and history
- Suborder
- Sauria
- Infraorder
- Anguimoprha
- Subspecies
- No
- Described by
- King & Thompson
- Moved to another genus · since it was first described
- No
- Described in
- 1968
- Type locality
- Mexico
Keeping one
19 in × 19 in × 12 in(48 × 48 × 30 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes ground-dwelling species at 4 × 4 × 2.5 times snout-vent length.
Lives on rock, so stable hard surfaces and basking ledges suit it.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own snout-vent length of 4.75 in (120 mm), at 4 × 4 × 2.5 times it, following the German federal welfare standard — how this is worked out.
Active animals measured in the wild averaged 78 °F (25.5 °C).
Mean body temperature of active individuals measured in nature. A measurement of the animal, not a setting for a thermostat.
Feeding
5kJ per day
Worked out for an animal of 39 g, the heaviest recorded for Mountain Knob-scaled Lizard — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.
An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.
What nobody knows
These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Length nose to tail · greatest recorded
- — Female length · mean, nose to tail
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body mass · adult female, mean
- — Body mass at hatching
- — Longest recorded life
- — Preferred body temperature · chosen in a laboratory gradient
- — Diet
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How it hunts
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — Clutches a year · fewest
- — Clutches a year · most
- — First breeds from · youngest recorded
- — First breeds by · oldest recorded
- — Hatchling length · smallest recorded
- — Hatchling length · largest recorded
- — Age at first breeding · female
- — Mature from · youngest recorded
- — Mature by · oldest recorded
- — Size at maturity · smallest recorded
- — Size at maturity · largest recorded
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Sex decided by
- — Conservation status
- — Status assessed · the year the Red List last looked
- — Population trend
- — Red List criteria
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Habitat
- — Active in
Others in Xenosauridae
- Arboreal Knob-scaled Lizard
- Chin-spotted Knob-scaled Lizard
- Flathead Knob-scaled Lizard
- Knob-scaled Lizard
- Newman's Knob-scaled Lizard
- Pallid Knob-scaled Lizard
- Pena's Knob-scaled Lizard
- Rackham’s Knob-scaled Lizard
- San Martin Knob-scaled Lizard
- Zacualtipá́n Knob-scaled Lizard
- Xenosaurus fractus
- Xenosaurus mendozai
Take this data
Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.
This species as JSON · the whole dataset
Cite this page
The Reptile & Amphibian Encyclopedia (2026). Xenosaurus agrenon. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/xenosaurus-agrenon
@misc{xenosaurus_agrenon_2026,
title = {Xenosaurus agrenon},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/xenosaurus-agrenon}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- Catalogue of Life (dataset 3LR), used under CC BY.