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Fossil evidence from the Burgess Shale in Canada has provided significant clues reguarding Priapulids.
510 million years ago during the Cambrian Period, the world was different.
According to paleogeographic records, the Burgess Shale site in Canada was warm and tropical.
Abundant coral reefs allowed ancient life to thrive in the area.1
Shown here on the right is a view of what scientists think the Burgess Shale looked like long ago.
Typical fossils found are simply the hard structure or bone remains of creatures.
Creatures without these structures are very difficult to fossilize due to their soft body structure.
Fossilization of such animals need special conditions such as the fine mud slide that occured
550 million years ago. The Burgess Shale site presented such contitions.
Due to an avalanche of fine mud sliding down from the reef top above millions of years ago,
some of the animals in mid-water could have been caught and any creatures on the ocean floor
were overwhelmed by the mud. The fine mud "penetrated and filled all available spaces within
the animals, thus preserving the shapes and locations of all the soft parts."2
This created fossils of soft-bodied, invertebrate animals, which is a rare event.
One of the many primative animals found at the Bugess Shale is this Ottoia Prolifica,
a primative Priapulid worm. "This creature lived in a U-shaped burrow that is constructed
in the substrate." 3 You can see it trying to eat another animal in the bottom right
part of the picture above.
"There are five species of priapulids whose present-day representatives have similar retractable
spiny proboscis and annulated body to Cambrian priapulids." (Clarkson, 1986) There is a close
relationship between Kinorhynchs and loriciferans with similarities in their cuticles.
"Kinorhynchs and loriciferans have a well-defined, non-inversible mouth cone which is not
found in priapulans. The priapulans are therefore reguarded as the sister group of these
two phyla. (Nielsen, 1996)
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Basics