Ancient slowpoke
By Sid Perkins
A 1-centimeter-long, 505-million-year-old fossil from British Columbia connects two lineages of marine invertebrates from the Cambrian period that scientists hadn’t previously linked.
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One group, the halkieriids, protected themselves with plates and mineralized shells—”like armored slugs,” says Simon Conway Morris, a paleontologist at the University of Cambridge in England. Wiwaxiids, the other lineage, carried spiny plates. The newly described creature, Orthrozanclus reburrus, had a shell at the front and spines all around (inset: artist’s reconstruction). In the March 2 Science, Conway Morris and Jean-Bernard Caron of the Royal Ontario Museum in Toronto argue that O. reburrus, halkieriids, and wiwaxiids should be put together in a new group. The researchers speculate that the proposed group included various ancestors of modern-day mollusks, annelid worms, and brachiopods.