Also new
Sentai which comes from Abaranger 21
Kira's transformation to Super Dino Mode is Sentai stock footage.
Could be new but not sure
Definitely Sentai
Conner and Ethan's changes to Super Dino Mode are Sentai stock footage.
Dr. O in Fossilized Amber
New footage of the White Ranger as seen on the Monitor  
This shot could be new footage as well and based on the left arm positioning, I believe it is new
Once you see the Dragozord and Stegozord, that is Sentai footage however that's Sentai stock footage.
Back to regular Sentai
The shot of the Dino Stegozord that plays on Dr. O's Computer Equipment is from Sentai.
Once you see the Brachiozord is when the Sentai stock footage begins.
Back to regular Sentai footage
Once the Thundersaurus Megazord forms, it then cuts back to regular Sentai footage of the Dino Stegozord.
This shot of the Ankylozord is pulled from another Sentai ep but couldn't tell you which one
This is when it goes back to regular Sentai footage from Abaranger 21
The Dino Stegozord vs Thundersaurus Megazord footage that plays on the Island Fortress Sentai footage is Sentai footage.
It then cuts to more additional Sentai footage of the Megazord battle from Abaranger 21.

NOTE: All Sentai footage comes from Abaranger 21 except for the 2 shots of Ankylozord.