Colorado Springs Fossils

The Plants and Mammals

Literally everything alive today can trace its ancestry back to the survivors of the asteroid impact, including humans. As a result, what we know today as the “modern world” was shaped by the recovery. The discoveries at Corral Bluff set the scene for the first one million years after the asteroid impact.

In the aftermath, ecosystems are completely devastated and extinction occurs everywhere on the planet, on land, and in the sea. All large animals are wiped out. The biggest animal to survive the mass extinction is a soft-shelled turtle weighing about 200 pounds; the largest surviving mammal weighs about a pound.

Taenoilabis Taoensis

It's name means "ribbon lips"

  • Age: First appeared 720,000 years after the K-T extinction. 
  • Size: 34-56 kg; comparable to a small capybara
  • Belongs to an extinct group of mammals called “multituberculates,” arguably the most successful group of mammals that were around for over 150 million years. 
  • Fun facts: We hypothesize that they likely ate legumes and were river dwelling creatures. It was the largest multituberculate to ever live. 

Taeniolabis Skull

Carsioptychus coarctatus

Named after the oblique folds found on the teeth.

  • Age: First appeared 300,000 years after the K-T extinction. 
  • Size: ~30-47 kg  
  • One of the earliest relatives of living hoofed mammals (deer, cows, elephants, horses, etc.).  
  • Fun facts: This species represents the second major jump in body size, from 0.5 kg mammals that survived the K-T extinction, to ~6 kg mammals found ~100,000 years later, to Carsioptychus (~30kg), tipping the scales and 30 kg. Teeth suggest it was a hard object feeder (e.g. nuts); represents the first specialization in diet (from omnivore to herbivore) after the K-T extinction.


Eoconodon Coryphaeus

  • Age: First appeared 680,000 years after the K-T extinction. 
  • Size: ~47-77 kg, about the size of a wolf.  
  • One of the earliest relatives of living hoofed mammals (deer, cows, elephants, horses, etc.).  
  • Fun fact: It has a large hole above its teeth, suggesting a large nerve, which means it had a very sensitive snout (and likely had long, dense whiskers (vibrissae) for sensing its surroundings).

Eoconodon Skull

Loxolophus sp.

  • Age: First appeared 300,000 years after the K-T extinction. 
  • Size: ~4-6 kg, about the size of a raccoon. 
  • One of the earliest relatives of living hoofed mammals (deer, cows, elephants, horses, etc.).  
  • Fun fact: Likely belongs to a new species of extinct mammal. 

Loxolophus Skull

Forked Fern Gleichenia sp.


On the scorched landscape, a blanket of pioneering ferns, proliferating in sunshine where there were once shaded forests, quickly turns barren dirt into fields of green. They pave the way for a handful of other plants and the planet revegetates. Although the world is green again, this ecosystem has little diversity and endures for hundreds of thousands of years. The recovery is slow and patchy. 

The field of ferns gives way to low-diversity forests, often completely dominated by palms. This weird palm world lasts for approximately 300,000 years. Within this palm-dominated forest is the first major jump in mammalian size—an increase in body mass of 30 times, from the shrew-size survivors to a raccoon-size trailblazer. 

Palm Fronds Sabalites Imperialis

Within 300,000 years after the mass extinction, the forests start to regain their diversity, particularly walnut trees which may have provided an energy-rich food source for mammals. There’s a shift in mammals, from small omnivores to much larger herbivores tipping the scales at about 70 pounds. Legumes appear 700,000 years post extinction, as evidenced through the oldest bean pod found at the site. These “protein bars” provide a substantial food source for even larger herbivorous mammals, up to 100 pounds. At this point there is a 100-fold increase in body size compared to the tiny survivors of the asteroid. A comparable increase in body size in mammals will not occur for another 30 million years.

Bean pod legume

Because plants can’t get up and move, they reflect the climate in which they grew. In the Corral Bluffs section, there was a cooling leading up to the asteroid impact, and then a strong warming right afterward. These patterns link to the same patterns found elsewhere on Earth, including in the deep oceans. The whole global system—from the bottom of the deepest sea to the forests of the continents—is intricately tied and responds more or less in lockstep to climate change. In the Corral Bluffs section, we see that diversity of life, particularly the forests, increases as the climate warms. The plants also tell a story of climate change before and after the extinction.

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