UC Berkeley
Take a good look at the fossil and reconstruction of Opabinia. 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 Opabinia 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 Opabinia part of the arthropod lineage?
Yes No
Nice try, but maybe we should have shown you the hint first:
Arthropods have segmented bodies and jointed legs. Opabinia had a clearly segmented body — but did it have jointed legs? Look closely at the fossils and reconstructions above. Each body segment has two pairs of flaps. One pair was a simple flap and was probably used for swimming — but these were not jointed. The second pair looks striped in the reconstruction above. These stripes are the imprints of gill layers and were used for getting oxygen from the water.
Arthropods have segmented bodies and jointed legs. Opabinia had a clearly segmented body — but did it have jointed legs? Look closely at the fossils and reconstructions above. Each body segment has two pairs of flaps. One pair was a simple flap and was probably used for swimming — but these were not jointed. The second pair looks striped in the reconstruction above. These stripes are the imprints of gill layers and were used for getting oxygen from the water.
Get a hint
Arthropods have segmented bodies and jointed legs. Opabinia had a clearly segmented body — but did it have jointed legs? Look closely at the fossils and reconstructions above. Each body segment has two pairs of flaps. One pair was a simple flap and was probably used for swimming — but these were not jointed. The second pair looks striped in the reconstruction above. These stripes are the imprints of gill layers and were used for getting oxygen from the water.