Take a good look at the fossil and reconstruction of Pikaia. 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 Pikaia 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 Pikaia part of the arthropod lineage?

Yes     No

Nice try, but maybe we should have shown you the hint first:
At first glance, Pikaia might look like it had a segmented body, but those "segments" are actually just the imprints of muscle bundles — like the ones shown on this modern amphioxus.

Get a hint

At first glance, Pikaia might look like it had a segmented body, but those "segments" are actually just the imprints of muscle bundles — like the ones shown on this modern amphioxus.