The nektaspids were one of the most unique-looking groups of artiopodans, with soft-shelled unmineralized bodies, no eyes, and large head and tail shields with very few actual body segments in between – varying from 6 all the way down to none at all.
First appearing in the fossil record around 518 million years ago, only a few different species are known but they appear to have been abundant animals distributed in outer shelf waters worldwide during the Cambrian.
Their classification has traditionally been uncertain but specimens with well-preserved limbs show very trilobite-like leg anatomy, helping to place them in the artiopodans as potentially some of the closest “trilobitomorph” relatives to the actual trilobites.
Continue reading “Cambrian Explosion #52: Artiopoda – Who Needs A Thorax Anyway?”