A fossil that dates back to 555 million years ago and which left paleontologists speechless: it is the Quaestio simpsonoruman ancient animal discovered in the Nilpena Ediacara National Park, South Australia, which has an intriguing detail on its back: a question mark-shaped mark. This extraordinary feature, dating back to the Ediacaran period, prompted researchers to name the specimen “Question”, in reference to the tail which resembles a question mark. But the mystery doesn’t stop there.
The Quaestio simpsonorum It’s a real evolutionary puzzle. According to researchers at Florida State University, who published the discovery on Evolution and Developmentthis ancient animal is the first to have a defined axial polarity, that is, a clear distinction between front and back, and between left and right sides. A structural complexity that was not thought possible to be found in such ancient fossils. The presence of such features in fact challenges the consolidated idea that complex body plans appeared only during the Cambrian explosion, as underlined by the paleobiologist Scott Evans.
There are no other fossils from this period that have shown such organization so clearly. The animal, about the size of the palm of a hand, has a shape that resembles a question mark in the center of its body, highlighting a clear distinction between the left and right sides.
This complex structure suggests that the basic genetic mechanisms that allow us to distinguish sides of the body were already in use in organisms 555 million years ago.
Mobility and asymmetry: the surprising behavior of the Quaestio
But that’s not all. The Quaestio simpsonorum it was also a mobile animal, capable of moving by rotating on the seabed, a bit like a modern robot vacuum cleaner. This movement suggests that it was an epibenthic animal, capable of actively interacting with the surrounding environment, placing itself as one of the first animals to demonstrate this ability.
Another fascinating detail that emerged from the studies is evidence of chirality: an asymmetrical appearance of the body that resembles that of many modern animals, including humans. This discovery not only rewrites the history of animal evolution, but also allows us to better understand the developmental processes of the first living beings, as explained by Evans:
The ancient Ediacaran biota can tell us a lot about early animal development processes. Since animals today use the same basic genetic programming to form distinct sides, we can say with some confidence that the same genes were also operational in Questiondespite becoming extinct over half a billion years ago.
The paleontologist Mary Droser added:
The discovery, in addition to being an extraordinary window on the past, also offers us new perspectives for future research on life outside our planet. As we search for life on other planets, it is helpful to look back in time here on Earth to understand how life evolved and how it might develop elsewhere.
