My albino iguana girl, Gerine with more amargasaurus-ish features. They're one of my favorite dinosaurs. I went with the skin sail look because I think it looks awesome even if it's unlikely they had them. I like to imagine them as being flexible, thick skin for absorbing sunlight. From hips-down, the two rows of spines connect into one row the rest of the way down her tail, which is very firm and stiff, capable of whipping the shit out of just about anything. I also imagine she's about 12 or so feet tall.
Gerine is a highly saturated version of the creamy-orangey phase of albino iguanas rather than the neon yellow. She also is meant to have more exaggerated features found mainly/exclusively in male iguanas... slightly enlarged temporal lobes ("brain bumps"), longer dewlap, bigger, more impressive jowls & subtympanic scale (big, circular cheek scale] and nuchal crest (fatty bump on the back of her head where long spikes begin), which goes all the way down her spine. Also, her spikes are keratinous and flexible at the base, more like an iguana's than an amargasaurus' bony spikes. I play with my iguana's spikes sometimes while I'm petting him; I wag them around by squeezing his nuchal crest. He tolerates it pretty well XD
We don't know for sure that Amarga didn't have webbing..I say go nuts and go creative ! ;D