Complex sentence: They were generally small, and nearly all had become extinct by the end of the Jurassic Period, though least one anurognathid genus, Dendrorhynchoides, persisted to the early Cretaceous.
Split into simpler sentences: They were generally small, and all but the anurognathids had become extinct by the end of the Jurassic Period. At least one genus, the anurognathid Dendrorhynchoides, persisted to the early Cretaceous.