Wyo. Stat. § 2-9-102: Affidavit of survivorship; recordation; copy of death certificate to be attached.

If any person dies who is the owner of a life estate which terminates by reason of his death, or if any person dies who is the owner with his surviving spouse of an estate by entireties, or if any person dies who is the owner with another of a joint estate or an estate in joint tenancy, any person interested in the affected property or the title thereto may make the death a matter of record by recording in the office of the county clerk of the county in which the property is situate an affidavit describing the property, the instrument under which the estate was vested with appropriate references to its recording data if the instrument was recorded, and certifying under oath to the death of the decedent as the party who was named in and whose death terminated his previous estate in the property under the vesting instrument. The affidavit shall have attached thereto a copy of the official death certificate of the decedent, certified to by the public authority in which the original death certificate is a matter of record.