Does Alter Self qualify a player to take levels in Warshaper?

[Vault756]

Specifically does the Alter Self supernatural ability granted by having a Silver Dragon bloodline qualify the player to take levels in Warshaper? The more I look at Warshaper I don't think it does but I'm not 100% to be honest. It does specifically mention Silver Dragon in the Polymorph as spell-like section but Alter Self isn't Polymorph.

[Venger]

No, it does not. You can get in with change shape, being a (shapechanger,) casting polymorph, having polymorph as a sla, or having wild shape. Alter self is none of these, so does not qualify you.

[Silent Alarm]

No, it does not. You can get in with change shape, being a (shapechanger,) casting polymorph, having polymorph as a sla, or having wild shape. Alter self is none of these, so does not qualify you.
As stated here, it does not, however qualifying for Warshaper is trivial to qualify for. My personal favorite method, is to take Planar Touchstone and attune to the Wereglade. After you activate the higher abilities twice (turn yourself into a Werewolf for 8 hours per use), you gain the Shapechanger subtype for free and forever. After that, attune to the Catalogues of Enlightenment if you want, or some other touchstone if you feel the need.