Chalarodon madagascariensis Madagascar Iguana
Berenty Reserve, Toliara province, MadagascarOctober 18, 1996
Madagascar Iguana (Chalarodon madagascariensis)
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: