|A fossil of Siphusauctum gregarium|
Now Dr Jean Bernard Caron, curator of the Royal Ontario Museum's collection of invertebrate fossils, amongst which is the largest collection of Burgess Shale specimens anywhere in the world, believes that he has identified yet another new species. The importance of the fossil beds were brought to light by the eminent Stephen Jay Gould. In his book, Wonderful Life, he describes Doolittle Walcott as having 'shoehorned' all the fossils into existing phyla, failing to recognise differences between the species.
While this has been described as a harsh view of his work, it does hold some truth. It is for this reason that new species have been described from the old fossils. Dr Caron was looking at fossils of a strange, crinoid-like animal called Siphusauctum gregarium, when he realised that they were unlike any other members of the class they had been grouped into. Surprising, considering that it was one of the most common organisms at the Burgess Shale.
|A reconstruction of Siphusauctum gregarium|
It is likely that they were filter feeders, passing water through the openings, through the stomach, ejecting the waste water, whilst absorbing the nutrients via the gut. Even though its morphology has been reconstructed, its relationship with other organisms is unclear. While other stalk-based filter feeders have been discovered, a lack of small tentacles common to these means that it is not especially closely related to them. Its unique feeding system means that it is unlikely to be ancestral to organisms that either appear later in the fossil record or that are alive today. Dr Caron places it, therefore, in a completely new class of invertebrates.