Complex sentence: When we two years ago, they mentioned that their project has very close connections with WikiProject Paleontology and that your project had begun an image review process similar to that at WikiProject Dinosaurs.
Split into simpler sentences: When we two years ago, they mentioned that their project has very close connections with WikiProject Paleontology. They also mentioned that your project had begun an image review process modeled from the one at WikiProject Dinosaurs.