How Did Scientists Mistake a Fish for a Lemur?

Fossils are not always what they seem. Megarachne, once heralded as the largest spider of all time, was actually a sea scorpion. The squishy Cambrian critter Nectocaris has been transformed from one of our early chordate cousins to an enigmatic invertebrate of unknown affinity. Tracks thought to be left by an enormous hopping amphibian were later found to be scratch marks left by a giant, unknown invertebrate as it pulled itself along a Carboniferous shore. And, as I was reminded yesterday, there was the “lemur” that was a fish.