This paper describes a group of kin terms in Landuma (a Mel language spoken in northwestern Guinea) which have a non-standard phonological structure: they begin with the consonant cluster NC. It is shown that the anomalous properties of these nouns can be explained via their origin: all of them are borrowed from Mande. In Western Mande languages, nouns for elder kin are also anomalous in that they are often unable to adjoin a definite or referential article. It has been suggested previously that this anomaly could be explained by the presence of an archaic nasal prefix, a grammatical marker of elder kin. At the same time, such a nasal prefix is not attested in any modern Mande language. Two hypotheses can be advanced on the origin of the initial nasal element in the anomalous Landuma nouns. According to the first, this element goes back to a nasal prefix reconstructed for nouns referring to elder kin in Mande. If so, the Landuma data can be regarded as an argument for the relatively recent disappearance of this prefix in Mande (i.e., subsequent to the start of close contact between speakers of Proto-Landuma and speakers of Proto-Manding and Proto-Susu). Alternatively, the nasal element can be regarded as a reinterpreted Mande 1SG pronoun ń which, in its possessive function, appears frequently with kin terms. It cannot be excluded that both sources may have been relevant.