DNA has shown that the Nile crocodile is in fact two very different species: a bigger, more aggressive crocodile and a smaller, tamer species that today survives only in West Africa. While the taxonomy of the Nile crocodile has been controversial for over a century, the new study points out that the ancient Egyptians recognized the differences in the species and avoided the big crocodile for its rituals.
While it is not uncommon for DNA to overturn long-established taxonomy, in this case the DNA results of over a hundred living crocodiles across Africa and over fifty museum specimens—including mummified crocodiles from ancient Egypt—found that what has long been considered one species is two distantly related species. In fact the larger Nile crocodile (Crocodylus niloticus) is more closely related to Caribbean crocodiles than it is to the new cryptic species, dubbed Crocodylus suchus.
At first researchers were dumbfounded by these results.
"I kept on sequencing it because I was convinced I was 100 percent wrong," Evon Hekkala, lead author, told Nature. "It wasn't even remotely related to the Nile crocodile samples I had been working on."
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