You'll probably notice that they aren't there in any of the 2-series styles, but they still exist at the top of the thread in Amber and at both top and bottom in Blue (soon to be extinct).
Why? Well, for better or for worse, we're hoping that by getting users to use the "Reply To" button on each post they'll have a tendency to reply to a specific post rather than just any old post and that this, in turn, will assist those using the site in threaded or hybrid modes.
Does it work? There are mixed results, for sure, and some really dislike the change.
What am I going to do about it? I'm still thinking on that, when I can. Nothing immediately, but it does mean I'm leaving Blue around a little longer while I think.