The single (and special) ariga erua on side a seems to be half ariki, judging from the peculiar legs:

*Qa2-8	*Qa2-9	*Qa2-10	*Qa2-11	*Qa2-12	*Qa2-13 (36)
*Qa2-14	*Qa2-15	*Qa2-16	*Qa2-17	*Qa2-18	*Qa2-19

There are ariki glyphs also in Qa2-9 and Qa2-14. 2 * 9 = 18, 2 * 14 = 28, and 2 * 13 = 26 (ariga erua in Qa2-13). The ordinal number for ariga erua counted from Qa1-1 is 36.

Ariki glyphs serve in G the function of marking important distances from winter solstice. Here we have day 36 / 2 + 64 = 82 at ariga erua. But the calendar cycle in Q is not beginning at winter solstice, it is beginning - we have seen - 9 days later. 9 + 82 = 91 and the 'ariki ariga erua' glyph therefore marks the end of the first quarter counted from winter solstice.