mya=million years ago
Although it has been viewed as one of the less significant extinctions, some studies suggest that almost a quarter of all families became extinct at in the late Triassic, making it comparable in importance to the late Cretaceous extinction. Other studies suggest that there are at least two periods of extinction towards the end of the Triassic, between 12 and 17 million years apart.
Whether the extinction was a single event or a cluster of smaller events, there is no doubt that sponges, cephalopods, brachiopods, insects and many vertebrate groups lost many of their families as the Triassic drew to a close, some 208 million years ago. Conodonts disappeared completely, as did the Labyrinthodonts. While the losses may not have been as drastic as in other extinction events, they were important for a relatively new group of animals. As the loss of species opened up new opportunities, the dinosaurs were ready to take advantage.
the cause(s) of the Triassic extinction are poorly known, perhaps because it has attracted relatively little study, but climate change seems to be important and, in particular, an increase in rainfall.
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