Calinstel wrote...
How about head ridges that when hot extend back behind the skulls. Similar to those dinosaurs with the 'sail' on them. Iridescent colors flow over them in the sunlight? Nice for finding a mate 
How about scale like skin, reflective heat, does the iridescent glowing in sunlight. as they evolved singled a pleasurable response to outside stimuli much like purring with pretty color. its Sci-Fi so we don't have to overly realistic... They eyes are like cat eyes so glow comes from evolving as night hunters.. while reflective skin keep them cool during the hot days on Rannoch.