From 550 million years ago until 250 million years ago, brachiopods, or "lampshells," were plentiful in the earth's oceans. Today these shelly creatures that superficially resemble clams are rare, mostly lingering in cryptic habitats and subpolar regions of the oceans. But the fossil record, generously endowed with lampshells of diverse shapes, offers an impressive testament to the bygone glory of brachiopods.
A report in the June 17, 2005, issue of Science ("Secondary Evolutionary Escalation between Brachiopods and Enemies of Other Prey") by Michal Kowalewski and Alan Hoffmeister of the Virginia Tech Department of Geosciences, Tomasz Baumiller of the University of Michigan Museum of Paleontology, and Richard Bambach, Virginia Tech professor emeritus of paleontology now at the Harvard University Botanical Museum, indicates that attacks on Paleozoic brachiopods, as recorded by round drill holes bored in prey shells by some unknown drilling attackers, were rare but widespread and continuously present through the entire Paleozoic Era.
The researchers report that the frequency of drilled victims went up slightly in the mid to late Paleozoic, but these late Paleozoic attacks were still less frequent when compared to drill holes found in shells of brachiopods dredged from modern ocean floors. "These subtle increases in drill holes on brachiopods, from less than 1 percent in the early Paleozoic era to several percent today suggest that predators have become increasingly abundant and active through history of life," said Kowalewski, associate prof
Contact: Susan Trulove