Very interesting. One of the long standing mysteries about arthropods is how the 5 different major groupings of arthropods (all cheliceates related above belongs to one major grouping) are related to each other. Each anrthropod group appears on the surface to share enough similarities with all the other groups to suggest they must be fairly closely related, yet closer examination suggest the subtler differences between the groups is in fact fundamental. This dilemma has vexed evolutionary biologists so much that some of them have come to regard arthropods as a false grouping - that despite the long list of superficial similarities, the 5 groups were not related, and did not arise out of a common ancester that was itself also an arthropods. All the appearent similarities between insects, trilobites, centipedes, crabs, and spiders were the result of convergent evolution.
Currently the pendulum have swung back mid way, and bulk of evolutionary biology community seem to have moved back to the camp that argue arthropods are in fact closely related, but the last common ancester of all living arthropods might have been quite arthropody, but may not have been fully arthropod.
Currently the pendulum have swung back mid way, and bulk of evolutionary biology community seem to have moved back to the camp that argue arthropods are in fact closely related, but the last common ancester of all living arthropods might have been quite arthropody, but may not have been fully arthropod.
