New research from the University of New England (UNE) and Harvard University suggests the natural environment on the Caribbean island of Hispaniola barely changed over the past 20 million years.
The research, out this week in the Proceedings of the National Academy of Sciences (PNAS), is an insight into the evolution of the island via studying lizards native to the Dominican Republic and Haitian island.
The research confirms previous speculations that this group of lizards, known as anoles, have changed little in their physical features and in their diversity over the past 20 million years.
UNE’s Dr Emma Sherratt from the Palaeoscience Research Centre is the lead author of PNAS paper. She explained the team was able to identify the static evolution of the lizards by identifying their body shapes, toe-pads and skeletons fossilised in 20 million year-old fossilised tree sap and comparing with today’s generation.
“Amber is a great preserver of history. Because amber is translucent we are able to see the fossilised creature in such detail; its colour, how many scales it has on its toes, what it was last doing, whether its eyes are open or shut”, Dr Sherratt said.
This information has allowed the researchers to judge that the stability in the ecology of these anole lizards is most likely answered by the lack of change to the environment.
“In our explanation of these findings, we believe the environment on Hispaniola 20 million years ago would have looked very similar to today. Anole lizards which have recently migrated to Florida and other Southern USA states appear to be evolving rapidly and are physically quite different to those in Hispaniola, so we think that their historical consistency on the island is due to the consistency of the surrounding context.”
These lizards have been extensively studied by the scientific community and their ecological habits are widely understood. However, this study is the first of its kind to document the evolutionary history of the lizard species across millennia.
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