Prehistoric arms race: Soft-bodied creatures evolved skeletons as fortresses against attack Final Edition

• Published in: The Ottawa citizen (1986)
• Main Author: Stolzenburg, William
• Format: Newspaper Article
• Language: English
• Published: Ottawa, Ont Postmedia Network Inc 02.12.1990
• ISSN: 0839-3222

High in the B.C. Rockies, in an extraordinary 540-million-year-old fossil deposit called the Burgess Shale, a mid-Cambrian marine community comes to life. Like many less exceptional deposits, the Burgess harbors mild-mannered mollusks, trilobites (the ubiquitous, armored ''cockroaches'' of the Cambrian seas) and clam-like brachiopods (creatures with hinged shells and armlike feeding parts). In these waters lurked a lethal cast of predators, eyeing little shells with bad intent: Sidneyia, a flattened, ramheaded arthropod (the phylum of animals with jointed legs and segmented exterior skeletons), with a penchant for munching on trilobites, brachiopods and small cone-shelled creatures called hyolithids; Ottoia, a chunky burrowing worm that preferred its hyolithids whole, reaching out and swallowing them with a muscular, toothed proboscis; and even some trilobites with predatory tastes. They have reconstructed Anomalocaris, the largest of Cambrian predators. Fitting no other major animal design known, this half-metre-long ''terror of the trilobites,'' as [Derek Briggs] and [Harry Whittington] have called it, glided through the seas with ray-like fins and chomped with a ring of spiked plates that dispatched trilobite shells like a nutcracker, the two speculate. Its bite probably formed a W shape, nicely matching some of the trilobite wounds they have examined.