Is there a trick for figuring Latin names for animals?
As a general rule, the for those names is “no”. The Australian animal that was once called Platypus (“flat foot”) later became Ornithorhynchus (“bird beak”), because platypus had already been used for a beetle. If you looked at one, you would have no way of knowing how it had been named. Somebody might have decided it was a sort of southern beaver and called it Australocastor (“southern beaver”): it isn’t a beaver and that would be a poor choice, but it might have happened.