Chalarodon madagascariensis
—
Madagascar Iguana

This mostly nondescript little ground lizard distinguishes itself by having a dark spot on the top of its head that gives it the alternate common name "Three-eyed Lizard". The dark spot does indeed seem to have some rudimentary light-sensing ability.
Printed references:
- Glaw, F., Vences, M. 2007. A Field Guide to the Amphibians and Reptiles of Madagascar, Third Edition
- Glaw, F., Vences, M. 1994. A Fieldguide to the Amphibians and Reptiles of Madagascar, Second Edition
- Henkel, F., Schmidt, W. 2000. Amphibians and Reptiles of Madagascar and the Mascarene, Seychelles, and Comoro Islands
- Preston-Mafham, K. 1991. Madagascar: A Natural History