Reconstruction of the onychophoran Hallucigenia sparsa, from the Middle Cambrian Burgess Shale of British Columbia. First interpreted as walking stilt-like on its spines, this strange animal was reinterpreted when related specimens were later discovered in China. The Chinese fossils showed that the animal was probably a lobopod, armored with paired spines on the top and lobe-like walking appendages on the ventral surface. Not only had the animal been originally reconstructed upside down, but the head and tail had also been reversed. The size range of known fossils is 0.5 to 3cm long.