For decades, paleontologists have hypothesized that a major group of animals called ecdysizoans must be older than the Cambrian, but until now their origins have remained a mystery. discovery of Unkus Zaugishi A research team led by Professor Mary Droser at the University of California, Riverside says that the large gap between predictions based on molecular data and the lack of description of ecdysizoans prior to the rich Cambrian fossil record has been reconciled and animal life This will deepen our understanding of the evolution of .
Digital photography and 3D laser scanning Unkus Zaugishi body fossils. Scale bar – 10 mm. Image credit: Hughes others., doi: 10.1016/j.cub.2024.10.030.
Ecdysids are the largest and most species-rich group of animals on Earth, containing more than half of all animals.
Characterized by a cuticle (a tough external skeleton that is periodically shed), this group consists of three subgroups. Arthropods, including insects, spiders, and crustaceans. and Scaridophora, an eclectic group of small scaly marine creatures.
“Like many modern animal groups, ecdymozoans are prevalent in the Cambrian fossil record, and at the beginning of this era, about 540 million years ago, we see evidence of all three subgroups. We can,” said Ian Hughes, a graduate student in oceanography. Studied biology at Harvard University.
“We know that they didn’t suddenly appear out of nowhere, so the ancestors of all ecdysizoans originated in the preceding Ediacaran period (635 to 539 million years ago). It must have existed.”
“DNA-based analyzes used to predict the age of fauna by comparing it to its closest living relatives supported this hypothesis.”
“However, ecdysozoan fossil animals remain hidden among the large number of animal remains that paleontologists have discovered during the Ediacaran period.”
Newly described Ediacaran ecdysizoan, Unkus Zaugishi was only a few centimeters long.
Gathering of 82 people Unkus Zaugishi The specimen was discovered in Nilpena-Ediakara National Park in South Australia.
Dr. Scott Evans of Florida State University said, “Nilpena is perhaps the best fossil site in the world for understanding the evolution of early animals, because fossils occur during periods of increased diversity, and these “This is because we can excavate extensive rock formations that preserve snapshots of the world.” .
“The layer we found was Unkus Zaugishi It's especially interesting because the grains in the sediment are so small that you can actually see every detail of the fossils preserved there. ”
“We were excited to find evidence for what scientists have long predicted: the presence of ecdymozoans during Ediacaran times,” Hughes said.
“It’s also very important for understanding what these early animal groups looked like and their lifestyles, especially since ecdysizoans really came to dominate the Cambrian marine ecosystem.”
This finding is reported in the following article: paper in a diary current biology.
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Ian V. Hughes others. An Ediacaran bilaterian from South Australia with an affinity for molting animals. current biology published online on November 18, 2024. doi: 10.1016/j.cub.2024.10.030
Source: www.sci.news
