Study finds crocodile-like predator preyed on man’s ancestors

By Stephen Beech

A "dominant" crocodile-like predator with a big lump on its head preyed on man's ancestors three million years, ago, according to new research.

Early humans - embodied by the iconic hominin Lucy - would have lived in fear of the creature which lurked in lakes and rivers ready to attack them, say scientists.

Researchers have named the new species Crocodylus lucivenator, or Lucy's hunter.

The team, led by scientists from the University of Iowa, say the ancient reptile lived between 3.4 million to 3 million years ago, overlapping the time period and the region in Ethiopia with Lucy and her hominin species, Australopithecus afarensis.

Lucy’s skeleton, discovered in 1974, is noteworthy because it was the oldest and most complete early human ancestor or relative ever found.

It also provided further evidence that, in human evolution, walking on two legs, or bipedalism, preceded increased brain size.

The newly named crocodile ranged from 12 to 15 feet in length and adults weighed between 600 and 1,300 pounds, according to the new study published in the Journal of Systematic Palaeontology.

The research team say it was a "dominant" creature and the only crocodile on the landscape — an expanse of shrubland and wetlands pocked with rivers lined with trees.

They believe it was an ambush predator - silently submerged in the water, poised to spring on those who came around for a drink.

Professor Christopher Brochu, from Iowa's Department of Earth and Environmental Sciences, said: “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.

“It’s a near certainty this crocodile would have hunted Lucy’s species.

"Whether a particular crocodile tried to grab Lucy, we’ll never know, but it would have seen Lucy’s kind and thought, ‘Dinner.’"

Prof Brochu, who has been studying ancient crocodiles for 35 years, first looked at Crocodylus lucivenator specimens when he visited a museum in Addis Ababa, Ethiopia, in 2016.

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He said: “I was just blown away because it had this really weird combination of character states."

Prof Brochu says that notable among the crocodile’s peculiar physical traits was a large hump in the middle of its snout, similar to what is found on the American crocodile but not seen with the Nile crocodile in Africa.

The research team believe the hump was used by the male crocodiles to attract a mate.

Prof Brochu said: “You see this in some modern crocodiles.

“The male will lower his head down a little bit to a female to show it off.”

He says Lucy’s hunter also had a snout that extended further from its nostrils than other crocodiles at that time, and that more closely resembles the lengthened snout in modern crocodiles.

The research team examined 121 catalogued remains - primarily skulls, teeth, and parts of jaws - representing dozens of individuals.

The fossils were excavated from the Hadar site in the Afar region of Ethiopia.

The region has produced multiple finds linking humanity’s ancestral past, including Lucy and her ilk, and was designated a UNESCO World Heritage site in 1980.

Study co-author Dr. Stephanie Drumheller explained that while most fossils were fragments requiring the researchers to extrapolate the full skeleton, one specimen had several partially healed injuries on its jaw that suggested it had tussled with one of its peers.

Dr. Drumheller, of the University of Tennessee, said: “The fossil record preserves similar injuries in extinct groups as well, so this kind of face-biting behaviour can be found throughout the crocodile family tree.

“We can’t know which combatant came out on top of that fight, but the healing tells us that, winner or loser, this animal survived the encounter.”

While there were at least three other crocodile species just south in the region, known as the Eastern Rift Valley, the Lucy’s hunter crocodile appeared to have its territory in Hadar to itself.

Co-author Professor Christopher Campisano, of Arizona State University, said: “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."

He added: “Interestingly, this crocodile was one of only a few species that was able to persist throughout.”