The 12th successor to the rulership at Tikal was Yellow Peccary, who was mentioned on two stelae (9 and 13). "Jones interpreted the eroded "father" glyph on Stela 13 as reading Stormy Sky, making Yellow Peccary the direct line 12th successor. The iconographic style of Yellow Peccary's two monuments bears no resemblance to the carved works of his father, specifically Stela 31. However, this perception was completely changed by the dramatic discovery in July 1996 of a new carved stela, Stela 40.
This stela was dedicated by K'an Ak [Yellow Peccary] and contains a stunning new series of dates for the lives of both his father, Siyah Chan K'awil [Stormy Sky] and of himself. New facts and dates in the lives of both rulers were revealed. The text goes on to say that K'an Ak acceded to power in Tikal on 24 August AD 458, 15 days following his father's final interment and that the Stela 40 itself was dedicated by K'an Ak on 20 June 468.
The dedication date is set at only 23 years after the dedication of Stela 31 and the styles are so closely shared as to suggest the same hand carving them. This is extremely helpful in understanding the succession as the inscriptions referring to K'an Ak on Stelae 9 and 13 are short and offer little information with few dates, in stark contrast to the historic record on stela 31. Some change in manner of presentation took place even though the descent line is intact. From a date on Stela 9, we know that K'an Ak was still ruling in AD 475 but no other dates for his reign are secure.
Peter Harrison, The Lords of Tikal, p. 92