More than three million years ago, our famous human ancestor Lucy and her relatives shared the East African landscape with fearsome predators. Hidden in rivers and lakes, giant crocodiles with distinctive humps on their snouts probably posed one of the greatest dangers to ancient humans.
Now, a University of Iowa-led team has identified the reptile as a previously unknown species. In a study published in Journal of Systematic Paleontologyresearchers officially described the crocodile and gave it a name Crocodylus lucivenatormeaning “Lucy’s hunter”.
Crocodile in Lucy’s time
The name reflects the animal’s place in history. This crocodile lived in what is now Ethiopia, at the same time and in the same area as Lucy and her species, between 3.4 and 3 million years ago. Australopithecus afarensis.
Discovered in 1974, Lucy became one of the most important fossil discoveries in human evolution. At the time, her skeleton was the oldest and most complete early human ancestor or relative ever discovered. The discovery also helped prove that upright bipedalism, known as bipedalism, evolved before brains became larger.
The newly identified alligator was a magnificent animal, measuring approximately 12 to 15 feet long and weighing between 600 and 1,300 pounds. It was the only crocodile known from the Hadar landscape, an environment that includes scrubland, wetlands, rivers, and tree-lined waterways. Researchers believe it was an ambush predator that spent much of its time hidden underwater, waiting for an animal to approach in search of water.
“It was the largest predator in that ecosystem, even more so than lions and hyenas, and it was the biggest threat to our ancestors living there at the time,” says Christopher Brochu, a professor in Iowa State’s College of Earth and Environmental Sciences and corresponding author of the study. “It’s almost certain that this crocodile hunted Lucy’s species. We don’t know if this particular crocodile tried to catch Lucy, but it probably saw Lucy’s kindness and thought, ‘Here’s dinner.'”
A strange and distinctive crocodile
Brochu has spent 35 years studying ancient crocodiles. he first investigated Crocodylus lucivenator A specimen taken during a visit to a museum in Addis Ababa, Ethiopia in 2016.
“There were some really weird combinations of character conditions that really freaked me out,” Brochu recalls.
One of this crocodile’s most unusual features was a prominent hump in the middle of its snout. Similar structures are found in American crocodiles, but not in African Nile crocodiles. Researchers believe the hump may have played a role in courtship displays.
“This is also seen in modern crocodiles,” Brochu said. The male shows off by bowing slightly towards the female.
This species also had a snout that extended further beyond its nostrils than other crocodiles living at the time. Researchers say this feature is very similar to the elongated snouts found in modern crocodiles.
Fossils reveal ancient behavior
To identify the new species, researchers analyzed 121 cataloged fossil remains, including fragments of skulls, teeth, and jaws from dozens of people. The fossils were recovered from the Hadar Formation in the Afar region of Ethiopia.
For decades, Hadar has been one of the most important sites for understanding human origins. In addition to fossils of Lucy and other early humans, the area contains a rich record of ancient wildlife and was designated a UNESCO World Heritage Site in 1980.
Most of the crocodile fossils were incomplete, so scientists had to reconstruct aspects of the animal’s anatomy. However, one specimen preserved evidence of a violent encounter. Several partially healed wounds on its jaw suggest it had fought another crocodile.
“This type of face-biting behavior is seen throughout the crocodilian family tree, as extinct groups have similar scars in the fossil record,” said Stephanie Drumheller, an associate professor at the University of Tennessee who received her PhD from the University of Iowa. “We don’t know which combatant survived that battle, but the healing tells us that the animal survived the encounter, whether it was the winner or the loser.”
Top predators of the hadal ecosystem
At least three other species of crocodiles lived further south in the Eastern Rift; Crocodylus lucivenator It seems that they almost monopolized the Hadar area.
“During the Pliocene, Hadar consisted of a variety of habitats, including open and closed forests, corridor forests, wet grasslands, and scrublands, along lake and river systems across time and space,” said study co-author Christopher Campisano, an associate professor in Arizona State University’s Department of Human Evolution and Social Change. “Interestingly, this crocodile was one of the few species that was able to survive.”
The study is titled “Lucy’s Peril: Pliocene Crocodiles of the Hadar Formation, Northeastern Ethiopia.”
Nathan Pratt and Daniel Leifert of the University of Iowa’s School of Earth, Environment, and Sustainability contributed to the research. Other co-authors include Getahun Tekle and Tomas Getachew from the National Museum of Ethiopia and Jason Head from the University of Cambridge.
Funding for the research was provided by the National Science Foundation, the Leakey Foundation, the University of Iowa Office of International Programs, and the Iowa College of Arts and Sciences.
