UC Berkeley
Take a good look at the fossil and reconstruction of Naraoia. Then compare what you see to the arthropod checklist below.
Use your mouse to hover over the image and zoom in. (Touch the image on a mobile device.)
Does it look like Naraoia inherited all of the characters of an arthropod?
- arthropod characters
- bilateral symmetry
- segmented body
- hard exoskeleton
- jointed legs
- many pairs of legs
Based on the available evidence, is Naraoia part of the arthropod lineage?
Yes No
At first glance, Naraoia may not seem to be segmented. But it's worth considering this trait more carefully. Horseshoe crabs, for example, are arthropods. From the top, they don't look segmented because their bodies are protected by a thick shield, but the belly-side reveals a different picture: many legs attached to a clearly segmented body. Is it possible that Naraoia was segmented after all?
Dorsal and ventral views of a horseshoe crab. Photos by B.R. Speer
Get a hint
At first glance, Naraoia may not seem to be segmented. But it's worth considering this trait more carefully. Horseshoe crabs, for example, are arthropods. From the top, they don't look segmented because their bodies are protected by a thick shield, but the belly-side reveals a different picture: many legs attached to a clearly segmented body. Is it possible that Naraoia was segmented after all?
Dorsal and ventral views of a horseshoe crab. Photos by B.R. Speer