Hallucigenia is a genus of lobopodian known from Cambrian aged fossils in Burgess Shale-type deposits in Canada and China, and from isolated spines around the world. The generic name reflects the type species' unusual appearance and eccentric history of study; when it was erected as a genus, H. sparsa was reconstructed as an enigmatic animal upside down and back to front. Lobopodians are a grade of Paleozoic panarthropods from which the velvet worms, water bears, and arthropods arose.
Hallucigenia
Specimen with obvious spines
Restoration of H. sparsa
Lobopodians are members of the informal group Lobopodia, or the formally erected phylum Lobopoda Cavalier-Smith (1998). They are panarthropods with stubby legs called lobopods, a term which may also be used as a common name of this group as well. While the definition of lobopodians may differ between literatures, it usually refers to a group of soft-bodied, marine worm-like fossil panarthropods such as Aysheaia and Hallucigenia.
Fossils of Xenusion, a lobopodian that might have grown up to 20 centimeters.
Fossil of Jianshanopodia decora, showing head region (upper left) compose of robust frontal appendage (right) and pharynx with rows of teeth (bottom left).
Fossilized posterior trunk region of Jianshanopodia decora, showing traces of lobopods, gut diverculae and lobe-like terminal extension.
Fossil of Microdictyon sinicum, showing pairs of sclerite and trace of trunk and lobopods.
