10 Fascinating Microfossils According to La Brea Tar Pits' Researchers
At natural history museums, it's the big dinosaur bones or sabertooth cats that get all the attention, but as researchers are now finding, it is the tiniest of fossils that deserve attentionwhen answering some of Earth's most pressing questions.
We asked the researchers at La Brea Tar Pits what microfossils have caught and kept their attention. Here's what they had to say.
Oak Leaves Fossils
"The oaks of La Brea are always among my favorite fossils to work with. The preservation can be so spectacular, you feel like you’re working with acorns or leaves you picked up from a trail just yesterday," said biogeographer Jessie George, "It’s an amazing feeling to work with such a familiar presence in Los Angeles today that, in reality, might be 50,000 years in age. For me, it’s the closest you can get to time travel."
Juniper Seed
George also appreciates the juniper seed microfossils. "Juniper seeds are some of our most common plant fossils at La Brea, but they’ve also historically been under-appreciated for the stories they’re able to tell. They hold a lot of exciting potential for how L.A.’s climate and landscape was changing in response to events like extended periods of drought in a time when so much of the continent was covered in ice."
Rodent Droppings
Poop got Laura Tewksbury's attention. A senior preparator at La Brea Tar Pits, she said that at first they had thought this rodent poop (or coprolites, to be scientific) was from a urban rat that got into their sample, but as the researchers noted more pellets appearing encased in asphalt they realized that "There's no way that much is contamination." These fossilized fecal pellets are the first ever to be found in asphalt. Radiocarbon dates generated at UC Irvine confirm they are about 50,000 years old.
"Our packrat coprolites [fossil poops] are my current favorite microfossils because they are direct evidence of what these animals were eating about 50,000 years ago, and I am grateful to our small friends for allowing us to learn about what the environment was like in this specific place, at that specific time."
... and Many Others
Dr. Emily L. Lindsey, assistant curator at the La Brea Tar Pits, had a lot of many microfossils and offered a variety that had caught her eye including: a leaf fragment, a lizard jaw, a rodent tooth, a freshwater clamshell, an insect leg, a rodent claw, an insect wing and a juniper berry. "The vast majority of species we find at the Tar Pits [can still be found], and mostly residing in the L.A. area today. Understanding these stories of resilience in the face of significant past climate changes, landscape modification, and species introduction and extinctions, is incredibly important as we try to support species in weathering similar changes." Lindsey said that not only can these L.A.-based species tell us the changes they lived through, but their size, shape and chemical signatures in their bones can help scientists figure out how they changed their lifestyle and diets to adapt.
