Crocodile Ancestor Found Near World's Largest Snake
(Acherontisuchus guajiraensis, a 60-million-year-old ancestor of crocodiles. Titanoboa, the world’s largest snake, is seen in the background. Image: Florida Museum of Natural History illustration by Danielle Byerley
Remnants of a 20-foot extinct relative of crocodiles have been discovered in the same Colombian coal mine where Titanoboa, the world's largest snake, was found.
The findings, outlined in the journal Paleontology, suggest that members of these two predatory species might have fought to the death 60 million years ago. Titanoboa measured an incredible 42 feet long. ("Sue," the famous Tyrannosaurus rex specimen housed at the Field Museum, was about that long too.)
It sounds like the huge croc-like animal had an advantage over the snake, though. Its jaws alone were incredibly formidable.
(Jaw bone of Acherontisuchus guajiraensis compared with that of another ancient crocodile relative known from the site. Image: Florida Museum of Natural History photo by Kristen Grace)
"The younger individuals were definitely not safe from Titanoboa, but the biggest of these species would have been a bit much for the 42-foot snake to handle," lead author Alex Hastings, a graduate student at the Florida Museum of Natural History and UF's department of geological sciences, was quoted as saying in a press release.
(Alex Hastings displays a pelvic bone of Acherontisuchus guajiraensis. Image: Florida Museum of Natural History photo by Kristen Grace)
There's little doubt that Acherontisuchus guajiraensis and Titanoboa competed for food. The former evolved to hunt and eat fish, which the snake also consumed. The genus, Acherontisuchus, is named for the river Acheron from Greek mythology, “the river of woe,” since the animal lived in a wide river that emptied into the Caribbean. Its snout was long, narrow and full of pointed teeth, perfect for grabbing lungfish and relatives of bonefish that inhabited the water.
The new species is a dyrosaurid, believed to mostly have been ocean-dwelling, coastal reptiles. The new adult specimens challenge previous theories the animals only would have entered freshwater environments as babies before returning to sea.
During the Paleocene in South America, the environment was dominated by reptiles, including other giant snakes, crocodiles, and turtles. The dyrosaurid family originated in Africa about 75 million years ago, toward the end of the age of dinosaurs, and arrived in South America by swimming across the Atlantic Ocean.
(University of Florida researchers Jonathan Bloch, left, and Alex Hastings unearth fossils from the 60-million-year-old Cerrejon formation in northeastern Colombia, one of the world’s largest open-pit coal mines. Image: Florida Museum of Natural History photo by Edwin Cadena)
Dyrosaurids were key players in northeastern Colombia. Fossils reveal that their diversity evolved with environmental changes, such as an asteroid impact or the appearance of competitors from other groups, said Christopher Brochu, an associate professor of vertebrate paleontology in the department of geoscience at the University of Iowa, who was not involved in the study.
"We're facing some serious ecological changes now," Brochu said. "A lot of them have to do with climate and if we want to understand how living things are going to respond to changes in climate, we need to understand how they responded in the past. This really is a wonderful group for that because they managed to survive some catastrophes, but they seemed not to survive others and their diversity does seem to change along with these ecological signals."
One of the biggest catastrophes was the K-T probable meteor impact that killed much of Earth's life. The huge crocodile relative turned out to be bigger and stronger than this mega world disaster, though.
"The same thing that snuffed out the dinosaurs killed off most of the crocodiles alive at the time," Hastings said. "The dyrosaurids are one of the few groups to survive the extinction and later become more successful."
Maybe Titanoboa, after years of competition, helped to push A. guajiraensis to ever stronger heights.