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.
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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Around 540 million years ago, Earth's biosphere underwent a pivotal transformation, shifting from a microbe-dominated world to one teeming with animal life, as nearly all major animal phyla appeared abruptly in the fossil ...
Evolution
Feb 1, 2026
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Almost a hundred new animal species that survived a mass extinction event half a billion years ago have been discovered in a small quarry in China, scientists revealed Wednesday.
Paleontology & Fossils
Jan 28, 2026
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New fossil evidence from China suggests that some of our vertebrate ancestors had four eyes. The study, published in Nature, takes a closer look at a structure found in multiple 518 million-year-old fossils, which appears ...
The oldest fossilized remains of complex animals appear suddenly in the fossil record, and as if from nowhere, in rocks that are 538 million years old.
Paleontology & Fossils
Jan 6, 2026
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Skeleton season may be just around the corner, but the skeleton age dawned with the early Cambrian Period, about 538 million to 506 million years ago.
Evolution
Oct 15, 2025
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