bilineal

67 What the history of the lineage system suggests was surmised by anthropologist Marja-Liisa Swantz when she explained that "the Zaramo system was matrilineal and largely uxorilocal, but it had a clear bilineal emphasis, which made it highly adaptable."

Societies, Religion, and History: Central East Tanzanians and the World They Created, c. 200 BCE to 1800 CE 2008