According to the study, the height of the “pygmy elephant” was halved, and its body mass was reduced by approximately 85 percent over just 350,000 years after it evolved from one of the largest land mammals that ever lived.
The dwarf elephant is called “Palaeoloxodon mnaidriensisand became extinct about 19,000 years ago, having lost more than 8,000 kg of weight, and nearly two meters in height after diverging from the much larger straight-tusked elephants known asPalaeoloxodon oldIt was 4 meters long and weighed 10,000 kilograms.
The scientists analyzed molecular evidence from the remains of a pygmy elephant discovered in the Puntale Cave in Sicily, Italy, to calculate the rate of dwarfing of the species.
The specimen is believed to be between 50,000 and 175,000 years old. The researchers examined a piece of petrous bone – the part of the skull that holds the inner ear – known to preserve DNA better than other parts of the skeleton.
After examining the sample, the researchers found that the elephant’s weight and length decreased by up to 200 kg and 4 centimeters per generation, over a maximum period of about 352,000 years.
How did it shrink in size?
To put this process of dwarfism in a clearer context, the researchers say that reducing the size of the ‘pygmy elephant’ is comparable to that of modern humans shrinking to roughly the size of a rhesus monkey.
“The scale of the dwarfism resulting from this rapid evolutionary process is truly astonishing, resulting in a body mass loss of approximately 85 percent in one of the largest terrestrial mammals ever,” explains team member Axel Barlow from Nottingham Trent University, UK.
“As descendants of giants, the extinct pygmy elephants are among the most intriguing examples of evolution on the islands,” he adds.
The “dwarf elephant” lived on the European mainland between 40,000 and 800,000 years ago, and is believed to have colonized Sicily sometime between 70,000 and 200,000 years ago.
Researchers believe that the process of dwarfism began once the Sicilian elephant diverged from its mainland relative. Living in a secluded and secluded environment accelerated the evolution of the island’s creatures and soon a new species appeared, the “dwarf elephant”.
“By combining ancient DNA and fossil evidence, we can more accurately show the timing of observable evolutionary changes,” says Barlow.
Previous research indicates that island mammals are evolving three times faster than their continental counterparts. This rapid evolution may be explained by small initial populations and conditions that create different selection pressures than those on the mainland.
Pygmy elephants are an example of solitary dwarfism, the phenomenon whereby large terrestrial vertebrates (usually mammals) colonizing islands develop dwarf forms, a phenomenon attributed to adaptation to resource-poor environments and selection of early maturity and reproduction.
Some modern populations of Asian elephants have also undergone a smaller island size reduction, which has resulted in the emergence of pygmy elephant populations.