African Crocodiles are Seven Species, Not Just Three

Genetic analysis of Africa's iconic crocodiles has revealed that there are at least seven distinct species among them.

Historically, only three species of crocodile were recognized in Africa: Nile crocodiles, dwarf crocodiles and the slender-snouted crocodile. But several recent studies have revealed that there is more depth to these creatures than meets the eye.

A study published in 2009 in the journal Molecular Phylogenetics and Evolution revealed that there are actually three species of dwarf crocodile. This discovery was followed by a 2011 study published in Molecular Biology that reported the Nile crocodile is actually two very divergent species.

Now, the latest installment of the African crocodile saga is reported in the Proceedings of the Royal Society B: Biological Sciences. What was thought to be a single species of slender-snouted crocodile is actually two, the study authors report. Western populations of the reptile do not share the same genetic information or specific physical features as Central African populations.

"The West African slender-snouted crocodile is actually among the three or four most endangered crocodiles in the world," study leader Matthew H. Shirley said in a statement. "By finally recognizing that it is a unique species, we are in a much better position to advance its conservation and ensure its future."

James Austin, a geneticist at the University of Florida, is on the team who made the latest discovery, as well as the 2011 study. Austin said results emphasize how little is known about crocodile biogeography, or how species are distributed geographically over time, in Western and Central Africa.

Austin and his colleagues estimate that the two species of slender-snouted crocodile have been separated from each other geographically for at least 7 million years.

In an email to Nature World News, Austin said that the realization that there are more species of crocodiles in Africa than previously believed is significant because of how prominent an example it is of the under-represented biodiversity in West and Central Africa.

"There is likely much unknown diversity right under our noses," he said.

In addition to scientific implications, the study could also have major implications for animal conservation policy as well. "Apart from being of interest from a biodiversity perspective, knowledge of what species level diversity is out there can have very important conservation implications," Austin said. "In the case of the slender-snouted crocodile, the newly identified lineage in Western Africa is under immense pressure from over-harvesting for bush-meat and skins, as well as accelerated habitat loss."

The researchers likened the West African slender-snouted crocodile to the American alligator in that it was on the verge of extinction but not doomed. The American alligator faced similar threats of extinction in the 1960s, but a conservation campaign significantly boosted the species' numbers.

But whatever is done to ensure the endangered species' survival, it must be done quickly.

"There will need to be some fairly rapid assessments of conservation status of the western slender-snouted crocodiles," Austin said.