Rune Priest = Rune Priest. Space Wolves don't have familiars.
What's in your Codex is what's available to you-- units don't have multiple names and the units that aren't listed with a full entry are noted as references in Codex: Space Marines in Codex: Space Wolves. If you play Space Wolves, you have access to 0-1 Rune Priest, among other things, but cannot take any units from Codex: Space Marines apart from the ones specifically noted at the end of the Elites, Fast Attack, and Heavy Support sections.
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