Complex sentence: They were smaller than their cousins elsewhere in the world, for example he unearthed six-meter long sauropods, a groups of dinosaurs which elsewhere commonly grew to 30 meters or more.
Split into simpler sentences: They were smaller than their cousins elsewhere in the world. For example, he unearthed six-meter long sauropods, a group of dinosaurs which elsewhere commonly grew to 30 meters or more.