Two species of crocodiles dubbed "giant dwarf crocodiles" roamed in central and west Africa during the early and middle Miocene periods. Those creatures reportedly developed a taste for human ancestors, Science Daily reported.
Modern dwarf crocodiles rarely reached 2 feet long, but the ancient giant dwarf crocodile species were estimated to have reached 12 feet in length and were believed to be among the fiercest threats to any animal they encountered. Study corresponding author Professor Christopher Brochu said that the two species were opportunistic predators who pose a grave threat to ancient humans going to the river.
What Do the Two Crocodiles Look Like?
Crocodiles typically have scaly skin, small and cold eyes, flaring nostrils, a powerful jaw, and sharp, conical teeth that could rip off a limb in seconds. Those features are the reason why they are feared.
Researchers led by the University of Iowa discovered two new species of giant dwarf crocodiles they named Kinyang mabokoensis and Kinyang tchernovi. They have almost similar physical characteristics to modern crocodiles, except they had short, deep snouts, and nostrils opened up to the front and not straight upward. Also, they spent most of their time in the forest and not in the water, unlike today's crocodiles, The Weather Channel reported.
They also had conical, large teeth but had snouts that were short and deep. Brochu explained that the giant dwarf crocodile species had what looked like a big grin that made them look happy. However, that should not fool people because they will bite the face-off if given the chance.
They lived in the East Africa Rift Valley, which is now Kenya, during a time when the region was largely covered with forests. But around 15 million years ago, during a period called Miocene Climatic Optimum, both species mysteriously died out.
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Why Did the Giant Dwarf Crocodiles Vanish?
So, why did the giant dwarf crocodiles suddenly die out? Brochu believes that climate change led to less rainfall in the region which caused the gradual retreat of forests. According to EurekAlert! more grasslands and mixed savanna woodlands emerged because of that and the change in landscape affected the two giant dwarf crocodile species.
Researchers think that loss of habitat may have prompted a major change in the crocodiles in the area. Those changes are linked to the increase of the larger bipedal primates that gave rise to modern humans.
But these speculations are just hypotheses that Brochu acknowledges needed to be further tested to confirm. But researchers are unable to determine precisely when the two species became extinct.
Additionally, they saw a gap in the fossil record between the Kinyang lineages that existed about 7 million years ago. Scientists found that those crocodiles were the closest relatives of the Nile crocodiles living in Kenya today.
The full findings of their study, titled "Giant Dwarf Crocodiles From the Miocene of Kenya and Crocodylid Faunal Dynamics in the Late Cenozoic of East Africa," were published in the journal Anatomical Record.
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