SCIENCE LAB SCIENCE

Paleozoic Passion

Before there were birds or bees, this is how trilobites reproduced.

The sturdy, calcite-infused exoskeletons and their segmented shells are nearly ubiquitous in fossil deposits from the Cambrian Period to the Permian.

But this trove of trilobite fossils has revealed little about how the Paleozoic animals reproduced across 250 millions years of life on Earth.

A recently re-examined fossil from the Burgess Shale in the Canadian Rockies is pulling back the shroud of mystery over the ancient arthopods sex lives, and revealing that some trilobites most likely had a loving grip.

In a new study, Harvard Paleontologists. identified a pair of modified appendages that probably helped males of one trilobite species grasp females during copulation in a similar manner to that of modern horseshoe crabs.

The team examined several spiny Olenoides serratus trilobites collected from the Cambrian site.

While the Burgess Shale is known for its detailed preservation of even delicate tissue, one of the Olenoides specimens the team examined at the Royal Ontario Museum in Toronto looked more like a badly broken lobster tail than an intact trilobite.

''It's a sad-looking specimen - it's missing most of the head and half of the body,'' said Sarah Losso, a Ph.D, candidate at Harvard and an author of the study.

The fragmented nature of the specimen was a lucky break because it revealed the anatomy often hidden under a trilobite's shell. [Jack Tamisiea]