The two .exr textures are used to drive the specularity of the shader when rendering with Blender Cycles.
The model also features one alternate, more traditional brown texture, as shown in the first signature image. This is included as an additional file to download. This file can simply replace the original texture. To complete the traditional scaly rex look you can disable the feather particle system on the model within blender.
The model features somewhat speculative particle feathers along the neck and back, but these can easily be disabled for a more traditional 'scaly' look. Hair dynamics can easily be switched on in the particle settings tab for animation and have all their settings set up and ready for simulation.
The animal is fully rigged, with IK movement in the legs and a number of constraints set up to make animation easier. Controls are present for curling the fingers and toes, as well as for spreading the toes, eye direction, eye dilation and closing the eyelids.
Vert & poly counts are given unsubdivided. The model renders best at subdivision level 3 or higher. At subdivision level 4 vertex count is 1.21 million and poly count is 1.20 million.
Preview images were all rendered in Blender Cycles with filmic colour management & an HDR environment texture. Usable results can be obtained at 150 samples or higher, though I recommend rendering at 300-500 samples for a good balance of speed and quality.