Tom, merging teams is impossible, but renaming teams is simple. Since the original team has the most members and historical credit, it may be better to cut your losses with the new team, and consolidate using the old team (renamed appropriately).

Combined stats only go by the team name, so if you do the rename, you will magically get 20 million WCG points added. That's 3 million BOINC credits....

Well, if there is an AWOL captain, one of the existing and active team members could ask WCG to contact him (see Start Here FAQ for suggested procedure) and to free up the post to facilitate at least captain transfer and the integration of members, followed with the rename. Careful, as there is Argus eye watching, given the high noise level pertaining to a recent event where someone coordinated to rip teams on BOINC projects. That's though not possible at WCG with the established procedures.