Kin Groups and Descent. Gnau descent is reckoned patrilineally, and genealogies are traced to a much greater depth—between five and fifteen generations—than is commonly the case among New Guinea peoples. The descent groups are not localized in single villages, although in most cases a mythological charter connects the most distant known ancestors to specific locales. Within descent groups, individual lineages stand in "brother" relationships to one another. The largest descent groups, consisting of all people who trace patrilineal ties back to the founding ancestors and to associated ancient sites, are crosscut or even contradicted by local claims of direct ancestry, within which "brotherhood" may be ascribed by virtue of no criterion other than length of residence. Thus, although fairly accurate genealogies are maintained over a great many generations, agnation can and often is manipulated. For this to be done, however, any justification for claiming agnatic relationships is necessarily located in the remote past.
Kinship Terminology. Kinship terminology is based on the two concepts of "brotherhood" and "seniority," couched within the framework of a locationally defined descent group. All men who descended from the same founding ancestor and who are members of the same generation are classed as "brothers" and further distinguished as senior or junior with regard to one another.