When did arthropods go extinct?

Answer 1

Arthrpoda has an extinct class Marrellomorpha and an the extinct Trilobite subphylum. The order Eurypterida (eurypterids) or sea scorpions, related to arachnids are also extinct. They may have been the largest arthropods to have ever lived.

Answer 2

Trilobites are an entire extinct class. Within the arachnid class, eurypterids (giant sea scorpions) have been gone since the Devonian, and a little while later in the insect class griffinflies (giant dragonflies such as Meganeura) followed suit. That's the most prominent vanished groups. :)

Answer 3

Arthropods did not go extinct. There are more arthopods living on the face of the earth today than any other type of creature. So they are the most successful creatures ever lived!