What about the sequel to James Robert Smith The Flock?

Just finished reading The Flock by James Robert Smith and I liked very much. I read that apparently a sequel The Clan was written and to be released in 2011 or 2013 (I'm assuming by the title It would deal with prehistoric hominids or something like it) and some of the characters were the same from before. If anyone can tell me, was this novel not released yet or was it ?