The Earliest Arthropods and Other Animals

摘要

A bacterial mat cover of sea-bottoms during the lst Epoch of the Cambrian (the Ter-reneuvian) hindered entire bodies to be preserved. What we find is dominantly isolated parts, 'small shelly fossils'. More active burrowing then removed the mats, with the ap-parent 'explosion' of life forms in the 2nd Cambrian Stage as one of the results. Many phyla have their first fossil appearance in the 2nd Stage. Some of them were already `modern' in their morphology and have not evolved much since. The arthropods provide an interesting example of the opposite situation. They are represented by many species and by well-preserved fossils, many of which are surprisingly little derived. The materi-al thus opens for studies of the primary radiations. The related dinocaridids represent an interesting case of convergence including the development of segmented appendages. Both these groups have their roots among the lobopods.