Hox genes suggest that they both had a modular body plan of some sort. Triploblasty implies some complexity (the least complex triploblastic organism today is a flatworm).
I’d be very surprised if most recent common ancestor didn’t have neurons similar to most neurons today, as I’ve had a hard time finding out the differences between the two. A basic introduction to nervous systems suggests they are very similar.
This page on the history of invertebrates) suggests that our common ancestors had bilateral symmetry, triploblastic and with hox genes.
Hox genes suggest that they both had a modular body plan of some sort. Triploblasty implies some complexity (the least complex triploblastic organism today is a flatworm).
I’d be very surprised if most recent common ancestor didn’t have neurons similar to most neurons today, as I’ve had a hard time finding out the differences between the two. A basic introduction to nervous systems suggests they are very similar.