More than three million years ago, our ancient ancestors, including the iconic Australopithecus afarensis known as Lucy, roamed the African landscape. They faced numerous threats, one of which was a formidable crocodile species recently identified by a research team from the University of Iowa. This ancient predator, now named Crocodylus lucivenator or “Lucy’s hunter,” was a significant threat to early hominins.
The announcement of this discovery comes from a study published on March 12 in the Journal of Systematic Palaeontology. The research reveals that this crocodile species lived between 3.4 million and 3 million years ago, coinciding with Lucy’s era in the Ethiopian region. The name “Lucy’s hunter” aptly reflects its role as a dominant predator in the ecosystem shared with early human ancestors.
The Predatory Nature of Crocodylus lucivenator
The newly identified crocodile was an impressive creature, measuring between 12 to 15 feet in length and weighing between 600 and 1,300 pounds. It was the apex predator in its habitat, an ecosystem of shrubland and wetlands crisscrossed by rivers. According to the researchers, this crocodile was an ambush predator, lurking underwater to attack unsuspecting prey.
“It was the largest predator in that ecosystem, more so than lions and hyenas, and the biggest threat to our ancestors who lived there during that time,” says Christopher Brochu, professor in the Department of Earth and Environmental Sciences at Iowa and the study’s corresponding author.
Brochu, who has dedicated 35 years to studying ancient crocodiles, first encountered the Crocodylus lucivenator specimens during a visit to a museum in Addis Ababa, Ethiopia, in 2016. He was struck by the unique combination of traits exhibited by the fossils.
Distinctive Features and Behavioral Insights
One of the most notable features of Lucy’s hunter was a prominent hump on its snout, akin to the American crocodile but unlike the Nile crocodile found in Africa. Researchers believe this hump was used by males to attract mates, a behavior observed in some modern crocodile species.
“You see this in some modern crocodiles,” Brochu explains. “The male will lower his head down a little bit to a female to show it off.”
Additionally, the crocodile’s snout extended further from its nostrils than other crocodiles of its time, resembling the elongated snouts of modern crocodiles. The study involved examining 121 cataloged remains, primarily skulls, teeth, and jaw fragments, representing numerous individuals excavated from the Hadar site in Ethiopia’s Afar region.
Historical Context and Evolutionary Significance
The Hadar region, a UNESCO World Heritage site since 1980, has been a treasure trove of fossils linking humanity’s ancestral past. The discovery of Crocodylus lucivenator adds another layer to our understanding of the Pliocene epoch, a time characterized by diverse habitats, including woodlands, forests, and grasslands.
According to Christopher Campisano, associate professor at Arizona State University and a study co-author, the Hadar ecosystem was varied, supporting a range of species. However, Lucy’s hunter was one of the few species that persisted throughout the Pliocene.
“During the Pliocene, Hadar was composed of a variety of habitats alongside its lake and river systems over space and time, including open and closed woodlands, gallery forests, wet grasslands, and shrublands,” Campisano notes.
Implications and Future Research
The study, titled “Lucy’s Peril: A Pliocene Crocodile from the Hadar Formation, Northeastern Ethiopia,” highlights the complex interactions between early hominins and their environment. It underscores the role of predators like Crocodylus lucivenator in shaping the evolutionary path of our ancestors.
The research was supported by the U.S. National Science Foundation, the Leakey Foundation, and various academic institutions. Contributing authors include Nathan Platt and Daniel Leaphart from the University of Iowa, Getahun Tekle and Tomas Getachew from the National Museum of Ethiopia, and Jason Head from the University of Cambridge.
As scientists continue to unravel the mysteries of our ancient past, discoveries like Lucy’s hunter provide invaluable insights into the challenges faced by early human ancestors and the evolutionary pressures that shaped their development. Future research will likely delve deeper into the ecological dynamics of the Pliocene and the role of predators in human evolution.
