You may think that scientists know all there is to know about the animal kingdom, but consider this. Scientists conducting a three year study of caves in Kings Canyon Park in California discovered 27 previously unknown species, including spiders, centipedes and Psuedo-scorpions. Evidently, many of these species live only in caves. Some only live in one particular cave.
Who knows what else is out there? God's creation is huge, complex and varied.