Visitors to FossiLab, the fossil preparation laboratory in the ancient life halls of the Museum, see work that normally goes on behind the scenes at museums. They watch specially trained volunteers prepare fossils for scientific study, display, or storage in our enormous collections, and sometimes they witness exciting discoveries.
Most of the fossils we work on in FossiLab were found and excavated by Smithsonian paleobiologists (scientists who study ancient life), whose research takes them to remote places around the world. When the packing crates containing their discoveries arrive in FossiLab, we pull out our tools and get to work. Right now, we are cleaning T. rex foot bones, the skull of a brontothere (an extinct relative of horses and rhinos) embedded in a massive block of rock, and a couple of whale skulls. Removing all the rock from these behemoths is interesting and fun, but we often wish we’d been there when the fossils were discovered -- wouldn’t it be cool to be the first person to see something that had been buried in the earth for millions of years! That’s why we get so excited when we open a crate and find bags containing loose bits of broken-up rock, not “just another” T. rex bone. The lumps of sedimentary rock, or “matrix,” offer a chance to make fossil discoveries right here at the Museum!
When scientists go out prospecting for fossils, erosion is their best friend. Most of the “life” of a fossil is spent deep underground, encased in rock, and it is only after erosion slowly breaks apart the rock matrix covering it that a fossil can be discovered. Scientists searching for the fossil remains of big animals walk along eroding hillsides and look for bones protruding from the earth or for telltale bone fragments at the bottom of a slope. If they spot something that looks interesting, they remove the loose matrix and carefully trace the remains back into the hill, hoping to find more bone entombed in the rock.
But paleobiologists don’t always go for the big stuff. All fossils provide important evidence about the history of life, ancient ecosystems and environments, and for some research, finding the fossils of tiny creatures becomes Job #1. Prospecting for small fossils requires enormous patience and keen observation, and some people are really good at spotting bits of tiny bones and teeth eroding from the same outcrops that hold the fossils of larger animals. That is when shovels fill canvas bags with as much broken-up matrix as the scientists can carry, and crates full of matrix make their way to back to the Museum.
In FossiLab, we have time to do a more thorough search of the crumbling matrix. We use a microscope so that we can see even the tiniest bones and teeth, and we don’t have to contend with the dripping sweat, too-bright sunshine, blowing dust, and cramped muscles that make it so difficult to spot small fossils out in the field.
Lately, we have been looking through matrix from Petrified Forest National Park in Arizona, finding the pencil tip-sized teeth of very small reptiles, and even fragments of dinosaur teeth. This matrix was collected last spring by Museum paleobiologist Dr. Kay Behrensmeyer and her colleagues. The goal of their expedition was to find fossils of mouse-sized early mammals and evidence of the environments where they lived during the Late Triassic Period, more than 200 million years ago. Although the area was once wet and green, there is no water there today. The eroded badlands are so rugged, and the fossil-bearing rock outcrops so far from the road, that they had never been explored by paleontologists. Kay’s team solved the challenge of setting up camp near the outcrops by hiring Navajo wranglers from a nearby ranch to transport their gear and water on pack horses and mules. The scientists prospected and collected on the outcrop for nearly a week, and when the wranglers returned to help them pack out, bags of matrix began the journey to FossiLab tied to the saddle of a strong black mustang.
Now, new bits of interesting teeth and bones turn up regularly under the FossiLab microscope, while Museum visitors follow the fossil search in real time on a large TV screen. So far we’ve found no mammal fossils, but the other tiny teeth are providing lots of clues about life in Arizona during the Triassic – and the thrill of discovery at FossiLab.
Abby Telfer, FossiLab Manager, Paleobiology Department