What did trilobites go extinct?
By Donavyn Coffey - Live Science Contributor 12 hours ago
These armored animals survived for 270 million years.
(Image: © Shutterstock)
Trilobites are weird creatures — they look like giant swimming potato bugs wearing helmets, and lived on Earth for a whopping 270 million years. These armored invertebrates, whose species once numbered in the thousands, thrived in the oceans as they scavenged and dug for food, and even managed to survive two mass extinctions.
But about 252 million years ago, trilobites disappeared from the fossil record. What finally wiped out this class of resilient bottom dwellers?
The trilobite's disappearance coincided with the end-Permian extinction (also known as the Permian-Triassic extinction), the third and the most devastating mass extinction event. Volcanic eruptions in Siberia spewed enormous amounts of lava for around 2 million years, according to Melanie Hopkins, an associate curator of paleontology at the American Museum of Natural History in New York City. These fiery eruptions sent trillions of tons of carbon dioxide into the atmosphere, triggering ocean acidification, which in turn made it very difficult for marine animals to survive, according to a 2010 paper published in the journal Proceedings of the National Academy of Sciences. Up to 95% of marine species succumbed to the end-Permian extinction, also known as the Great Dying, including the trilobites.
The trilobites, however, had already started a downward spiral toward extinction by that point. "By the time you get to this mass extinction, there aren't that many trilobites around," Hopkins told Live Science. That's because environmental and evolutionary changes had whittled away at this class of creatures.
More:
https://www.livescience.com/why-trilobites-went-extinct.html?utm_source=notification
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Older article:
Research Sheds New Light on Life of Trilobites
Feb 17, 2014 by News Staff
A new study published in the journal Geology suggests extinct arthropods known as trilobites were likely able to venture into very shallow water of the upper portion of ancient tidal flats.
Trilobites by Heinrich Harder, 1916.
“Discoveries like this are so important because they are at the core of our understanding of early evolutionary breakthroughs,” said study lead author Prof Gabriela Mángano from the University of Saskatchewan.
Prof Mángano and her colleagues discovered a huge number of fossilized trilobite tracks in rocks from the Appalachian Mountains.
The fossils reveal trilobites moved closer to the land during the Cambrian explosion some 540 million years ago
The Cambrian explosion is when almost all modern groups of animals appeared for the first time in the fossil record and the tidal flats likely served as a rich area for the creatures to forage food and for nesting activities.
More:
http://www.sci-news.com/paleontology/science-trilobites-01766.html
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