One or two (or twenty or thirty) of you are sick of me posting links to renditions of "Meet the Flintstones" theme. So you'll be happy to know this is the last one for a while. If I come across other wonderful interpretations, I will share.
As with several early Hanna-Barbera TV shows, the original version of the song was performed by The Randy Van Horne Singers, a group formed in the late fifties. In addition to cartoon programs, it was also heard on many commercials and record albums and other places.
The composition of the group changed from time to time — at one point, Marni Nixon was in its ranks — and it disbanded in the early seventies. If Wikipedia is correct — and when, apart from much of the time, is it not? — Mr. Van Horne resurrected it after 2000, died in 2007 and as of 2018, it was led by Alan Wilson, who may be the gent on the far right in the maroon shirt.
This video, which was uploaded to YouTube in 2015, purports to be The Randy Van Horne Singers singing "Meet the Flintstones." I have no idea how many of these singers might have been on the original recording to the tune — perhaps none. Some look barely old enough to have watched the show…