The Cambrian is a geologic period of the Paleozoic Era, spanning approximately 539–485 million years ago, characterized by a major diversification of multicellular life known as the Cambrian explosion. It follows the Ediacaran Period and precedes the Ordovician. Stratigraphically, its base is defined by the first appearance datum of complex trace fossils such as Treptichnus pedum, and it is subdivided into series and stages based on biostratigraphic markers, particularly trilobites and small shelly fossils. The Cambrian is critical for calibrating early Phanerozoic evolutionary, paleoenvironmental, and tectonic reconstructions.
Scientists have uncovered the earliest fossil evidence of annelids (ringed worms) in Cambrian microfossils dating back approximately 535 million years ago. This discovery offers fresh insights into the origin and early evolution ...
Evolution
Apr 20, 2026
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Animal life is extraordinarily diverse and complex, having colonized almost all environments on Earth—from hostile hydrothermal vents in the deep sea to the skies across our continents. But the planet was not always teeming ...
Evolution
Apr 4, 2026
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Newly discovered fossils have given scientists their first real glimpse of when Earth made a crucial transition from plants and unrecognizably simple animals to the complex creatures that took over the world and would eventually ...
Evolution
Apr 4, 2026
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A newly discovered fossil site in southwest China has transformed our understanding of how complex animal life emerged on Earth, revealing that many key animal groups had already evolved before the start of the Cambrian Period. ...
Evolution
Apr 2, 2026
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It had been a long day of teaching for Rudy Lerosey-Aubril. As a reward, he returned to cleaning an intriguing Cambrian arthropod fossil he had recently received for review. At first, the specimen showed all the expected ...
Evolution
Apr 1, 2026
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The transition from water to land is a question that still intrigues scientists. Those ancient organisms would have needed to adapt to several new challenges to life out of water. So, how did they do it?
Evolution
Mar 27, 2026
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How can we measure time more than 500 million years into the past? A study recently published in Nature Communications by researchers at the University of Lausanne presents a new geological "rock clock" that allows major ...
Earth Sciences
Mar 17, 2026
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Researchers studying the soft-bodied Ediacaran biotas of the world generally accept that there are three distinct assemblages. The 575–560-million-year-old (Ma) Avalon Assemblage is best known from the Ediacaran of Newfoundland, ...
Paleontology & Fossils
Feb 26, 2026
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The Great Unconformity is a major gap in Earth's geologic record. The missing layer between Precambrian and Cambrian rocks represents a gap of around a billion years of history. Among much debate surrounding the cause of ...
A UT San Antonio-led international research team has identified chitin, the primary organic component of modern crab shells and insect exoskeletons, in trilobite fossils more than 500 million years old, marking the first ...
Earth Sciences
Feb 6, 2026
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