Millions of years ago, giant pygmy crocodiles roamed parts of Africa with admiration for our human ancestors.
In a new study, researchers led by the University of Iowa announce the discovery of two new species of crocodiles that roamed East Africa between 18 and 15 million years before mysteriously disappearing. This species, called giant dwarf crocodiles, is related to dwarf crocodiles currently found in central and western Africa.
But the giant dwarf crocodiles were much larger – hence the name – than their modern relatives. Pygmy crocodiles rarely exceed 4 or 5 feet in length, but the ancient forms reached 12 feet in length and were probably among the deadliest threats to any animal they encountered.
“They were the biggest predators our ancestors encountered,” says Christopher Brochu, a professor in the Iowa Department of Earth and Environmental Sciences and corresponding author of the study. They were opportunistic predators, just like today’s crocodiles. It was too risky for an ancient human to head to the river for a drink. »
The new species is called Kinyang mabokoensis And the Kinyang Chernovy. They had a short, deep nose and large conical teeth. Their noses are slightly opened up and forward, and not directly upward as in modern crocodiles. They spent most of their time in the woods, not in the water, waiting for prey to be erected.
“They had what looked like this big smile that made them really happy, but they’d kill your face if you gave them the chance,” said Brocho.
Kinyang He lived in the East African Rift Valley, in parts of present-day Kenya, during the early Middle Miocene – a time when the area was largely covered in forests. However, since the end of a period called the Miocene climatic optimum about 15 million years ago, both species seemed to disappear.
Why did they disappear? Brochu thinks climate change has reduced rainfall in the area. Decreased rainfall has led to a gradual retreat in the forests, giving way to the grasslands and mixed woodlands of the savannah. The change has affected the landscape KinyangWhich the researchers say likely prefer wooded areas for hunting and nesting.
“Modern pygmy crocodiles are found exclusively in forested wetlands,” says Brocho, who has studied ancient and modern crocodiles for more than three decades. Habitat loss may have caused a major change in the crocodiles in the area.
“These same environmental changes have been linked to the emergence of the large, bipedal primates that led to the emergence of modern humans,” Brochu adds.
Brochu gets to know why Kinyang Death requires additional testing, as researchers cannot accurately determine when the animals died. Also, there is a gap in the fossil record between them Kinyang And the lineages of other crocodiles that appeared about 7 million years ago. Among the new arrivals were relatives of the Nile crocodile, now in Kenya.
Brochu has examined specimens on several visits since 2007 to the National Museums of Kenya, Nairobi.
The research was funded by the US National Science Foundation, the National Geographic Society, the Leakey Foundation, the Wenner Gren Foundation for Anthropological Research, the Fulbright Collaborative Research Program, the University of Oxford’s Boise Fund, and the IUCN Crocodile Specialist Group. and the University of Iowa, Karl und Marie Schack-Stiftung Fund, Vereinigung von Freunden und Förderern der Goethe-Universität Frankfurt, and Ministerio de Universidades de España.
Material provided by University of Iowa. Original by Richard C. Lewis. Note: Content can be modified according to style and length.
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