Oi, Bruce! If you think the Quipu is extinct here is a media deader than disco.
The Lukasa was a mnemonic device once used by the Luba people of Zaire.
The Lukasa is a hand-held flat wooden object. The flat part is divided into male and female sections, and either studded with beads and pins, or covered with incised ideograms.
It was used to teach lore about cultural heros, clan migrations and the introduction of sacred rule. It was also used to suggest spatial positions of activities and oracles within the kingdom or inside a royal compound.
Lukasas were used to order the sacred prerogatives of officials with regard to their contact with earth spirits and the use of natural resources. Each Lukasa elicits some or all of this information but the narration varies with the oratory skill and knowledge of the reader. The Lukasa encodes not a symbolic representation of the information, merely a mnemonic, or spatial representation map of it.
The kinds of information encoded may include journeys, kings and courtiers, genealogies, and lists of clans.
The instrument was used by an association called the "Mbudye," who trained men of memory who could recall genealogies, royal lists and episodes in the founding of the kingdom.
It seems to me that this is not merely a single medium but an entire approach (mnemonic encoding as opposed to symbolic representation) that is disappearing from living media.