More than 3 million years ago, the famous early human ancestor Lucy and her relatives shared the landscape of East Africa with a formidable hunter. Hiding in rivers and lakes, a giant crocodile with a distinctive hump on its snout was probably one of the biggest threats to these ancient hominins.
Now, a team led by the University of Iowa has identified the reptile as a previously unknown species. In a study published in Journal of Systematic PaleontologyResearchers formally describe and name the crocodile crocodylus lucivatorMeaning “Lucy’s hunter.”
A Crocodile from Lucy’s Time
The name reflects the animal’s place in history. The crocodile lived in what is now Ethiopia between 3.4 million and 3 million years ago, during the same period and in the same area as Lucy and her species. australopithecus afarensis.
Discovered in 1974, Lucy became one of the most important fossils ever found in human evolution. At the time, its skeleton was the oldest and most complete early human ancestor or relative ever discovered. The discovery also helped demonstrate that walking upright on two legs, known as bipedalism, evolved before larger brain size.
The newly identified crocodile was an impressive animal, measuring about 12 to 15 feet in length and weighing between 600 and 1,300 pounds. It was the only crocodile known from the Hadar landscape, an environment that included scrub, wetlands, rivers and tree-lined waterways. Researchers believe it was an ambush predator that spent most of its time hiding in the water, waiting for animals to come up to drink.
“It was the largest predator in that ecosystem, even more than lions and hyenas, and was the greatest threat to our ancestors living there at that time,” says Christopher Brochu, professor in the Department of Earth and Environmental Sciences at Iowa and corresponding author of the study. “It is almost certain that this crocodile would have preyed on Lucy’s species. Whether any particular crocodile tried to capture Lucy, we will never know, but it may have noticed Lucy’s kindness and thought, ‘dinner.'”
A strange and distinctive crocodile
Brochu has spent 35 years studying ancient crocodiles. they checked first crocodylus lucivator Specimens during a visit to a museum in Addis Ababa, Ethiopia in 2016.
Brochu recalls, “I was just blown away because it was a really weird combination of character situations.”
One of the crocodile’s most unusual features was a prominent hump located in the middle of its snout. Similar structures are found in American crocodiles but not in Nile crocodiles of Africa. Researchers believe the hump may have played a role in courtship displays.
“You see it in some modern crocodiles,” says Brochu. “The male will bow his head slightly down in front of the female to show this.”
This species also had a snout that extended farther beyond its nose than other crocodiles living at the time. According to the researchers, this feature more closely resembles the long snouts seen 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 individuals. These 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 the Lucy and other early hominin fossils, the area has a rich record of ancient wildlife and was designated a UNESCO World Heritage Site in 1980.
Most crocodile fossils were incomplete, forcing scientists to reconstruct aspects of the animal’s anatomy. However, evidence of violent encounters is preserved in one sample. Several partially healed injuries on its jaw suggest that it had fought with another crocodile.
“The fossil record preserves similar injuries even in extinct groups, so this kind of face-biting behavior can be found throughout the crocodile family tree,” says Stephanie Drumheller, an associate professor at the University of Tennessee who is pursuing her doctorate at the University of Iowa. “We can’t know which combatant came out on top in that fight, but the treatment tells us that, winner or loser, this animal survived the encounter.”
Hadar ecosystem’s apex predator
Although at least three other species of crocodile lived farther south in the Eastern Rift Valley, crocodylus lucivator It appears that Hadar had the area largely to itself.
“During the Pliocene, the Hadar varied over space and time with its lake and river systems, as well as a variety of habitats, including open and closed woodlands, gallery forests, wet grasslands, and shrublands,” says Christopher Campisano, an associate professor in the School of Human Evolution and Social Change at Arizona State University and a study co-author. “Interestingly, this crocodile was one of the few species that was able to survive that entire time.”
The study is titled “Lucy’s Peril: A Pliocene Crocodile from the Hadar Formation, Northeastern Ethiopia.”
Nathan Platt and Daniel Leifert of the School of Earth, Environment and Sustainability at Iowa contributed to the research. Additional co-authors include Getahun Tekle and Tomas Getachew of the National Museum of Ethiopia and Jason Head of the University of Cambridge.
Funding for the research was provided by the US National Science Foundation, the Leakey Foundation, the University of Iowa Office of International Programs, and the College of Liberal Arts and Sciences, Iowa.