Beneath the arid soil of South Australia, a new piece of the evolutionary puzzle has been unearthed. A 555-million-year-old fossil provides an unprecedented glimpse into the emergence of the first animals.
Codename:
Quaestio simpsonorum. This prehistoric organism reveals a key step in the increasing complexity of life forms, long before the appearance of modern species.
Artistic representation of what scientists believe Quaestio simpsonorum looked like.
Image by Walker Weyland.
This discovery was made in the Nilpena Ediacara National Park, a site renowned for its Ediacaran period fossils. Researchers found valuable traces of evolution here.
Quaestio simpsonorum stands out for its left-right asymmetry, a rare characteristic. This evolutionary trait links it to current animals, marking a significant leap in biological diversity. This fossil also reveals footprints that suggest autonomous movement along the seabed. It is the first time such behavior has been identified in an organism from this era, further emphasizing its importance in understanding the early stages of animal life.
The team led by Scott Evans from the University of Florida has identified genetic similarities between Quaestio and modern animals, a bridge between past and present.
Its ability to move and feed on mats of microscopic algae makes Quaestio a precursor to more complex life forms. As excavations continue in this region, each new discovery enriches our view of the origins of complex life. There is no doubt that further clues about evolution are still waiting beneath the Australian soil.
What is left-right asymmetry in evolution?
Left-right asymmetry is a biological trait where the left and right sides of an organism show notable differences. Unlike perfect symmetry, observed in many primitive organisms, this asymmetry signals evolutionary complexity.
In animals, this asymmetry is often associated with specialized bodily functions. For instance, in humans, the heart is located on the left side, and the liver on the right. This organization is due to the expression of specific genes that guide the growth and positioning of organs during embryonic development.
The discovery of this asymmetry in
Quaestio simpsonorum shows that this mechanism already existed more than 555 million years ago. This means that the genetic foundations of body organization were already in place long before the emergence of more evolved animals, such as vertebrates.
Author of the article: Cédric DEPOND