Sorting creatures from another planet

Megan had a sheet of characters from a another planet.    They were all numbered and , without a classification key, she just looked at the creatures and made up pairs based on what they looked like and their body features, feet, , antennae, body coloration, wings, antennae, etc.   then her friend, who has vp been studying the creatures, comes up with a dichotomous key to sort the animals.  Megan paired most of them right originally, except 4,   I think this was because she paired them based on coloration ,  overlooking the fact that the ones of the same pattern of marks did not have the same feature when it came to legs. We discussed that this is an important feature as you would not pair a fish with a lion .   I thought this was a cute activity.   Megan would rather build or mix things.