September 22, 2016:

by Enrico de Lazaro

A 90-million-year-old fossil discovered in Morocco is the oldest known iguanian lizard from Africa, which could help tell the story of lizard evolution in southern continents, paleontologists say.

Iguania (chameleons, agamas, iguanas and New World lizards) is one of the most diverse groups of extant lizards, spanning from acrodontan iguanians (those with teeth fused to the top of their jaws) dominating the Old World to non-acrodontans in the New World, as well as Madagascar and a few Pacific islands.

The new fossil species, dubbed Jeddaherdan aleadonta, is an acrodontan lizard, constituting the first iguanian from the Mesozoic of Africa. It is the oldest known iguanian from Africa — about 40 million years older than the previous oldest acrodontan record from the continent.

The 90-million-year-old jaw of Jeddaherdan aleadonta was unearthed in the Kem Kem region of southeastern Morocco.

The lizard was contemporaneous with well-known reptiles from this region, such as the dinosaur Spinosaurus.

It belongs to the same group that is currently widespread in the African continent today, including Morocco. This indicates living African lizard lineages have inhabited that continent for at least 90 million years.

Jeddaherdan aleadonta is of a similar age, and has a number of similarities, to Gueragama sulamericana, a recently discovered lizard species from the Late Cretaceous of Brazil. This indicates important similarities between African and South American faunas at 90 million years ago.

Importantly, this was a crucial time in the history of the planet with the opening of the Atlantic Ocean taking place and separating Africa and South America.

The discovery is detailed in the September 2016 issue of the journal Royal Society Open Science.

“Jeddaherdan aleadonta has unique dentition, something that we cannot find in any close relative today.”

“Its unique dental morphology makes me wonder about its dietary or tropic specialization, and aspect of its biology that we might never be able to know with certainty.”

“Our knowledge of lizard evolution in the African continent is largely enigmatic. This finding reveals important similarities between South American and African lizard faunas in a distant geological past,” added co-author Dr. Tiago Simões, from the University of Alberta, Canada.

“The discovery of Jeddaherdan aleadonta also suggests new findings in Africa may provide crucial clues towards understanding the origin of both African and South American lizards.”

“Jeddaherdan aleadonta shows that similar acrodont lizards lived in South America and Africa before separation of the two continents by the South Atlantic Ocean,” said senior author Dr. Jean Claude Rage, from the National Museum of Natural History in Paris, France.

“Subsequently, acrodonts developped in Africa, but they disappeared from South America at an unknown time.”

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Sebastián Apesteguía et al. 2016. The first iguanian lizard from the Mesozoic of Africa. R. Soc. open sci. 3: 160462; doi: 10.1098/rsos.160462