When: Mid-Cambrian (515-500 million years ago)
Where: British Columbia, Canada.
What: Opabinia is one of the rarest forms from the Burgess Shale fossil lagerstatten. We have explored the Burgess Shale fauna before with Anomalocaris and Hallucigenia. Opabinia, unlike these other species, has not had a confusing history with various interpretations of its anatomy. This does not mean that 1.5-3 inch (4-7cm) long invertebrate is much like any modern form though! Far from it, Opabinia is unlike anything alive today. Much of its body resembled Anomalocaris, which it is possibly related to, but its head is where the most bizarre features were. It had 5 eyes and a proboscis up to 1/3rd of its length, ending in a form of gripping claw. This proboscis was flexible enough to curve around to its mouth, which was hidden on the underside of its head and directed posteriorly. It is thought Opabinia swam though the ancient seas by flexing its body, picking up soft bodied prey animals with this ‘trunk’. No traces of legs have been found in any of the ~20 or so fossil specimens.
Like most Burgess Shale taxa, the relationships of Opabinia are uncertain. It is somewhat hesitatingly placed as a stem arthropod in a lot of classifications, but this relationship is based in turn on an uncertain link with Anomalocaris. It is possible that Opabinia is far removed from all modern phyla. One of the biggest supports for this later view is its 5 eyes, a configuration never again seen in the history of life.
I might have gone a bit overboard with the images today, but this is one of my most favorite fossil forms! It is just so odd and different from anything else.