This verse is a conclusion to the opening identificatory colophon. Mormon identified himself as the writer in the first verse, and in this verse declares ancestral lineage and direct parentage. There is no reason to declare Mormon’s father’s name except as a statement of lineal position.
For more information on colophons, see the commentary following 1 Nephi 1:1. It is important to note that we have the best examples of colophons in the holographic writings. When Mormon writes his version of the texts, he does not include the colophon because it is not appropriate, as it is presumes a direct identification of the writer of the text.