SEDALIA, Mo. (AP) — Former state Sen. James Mathewson, the longest-serving President Pro Tem of the Missouri Senate, has died. His family said Mathewson died of cancer Monday evening at his home in Sedalia. He was 83. Mathewson, a Democrat, was first elected to the Missouri House in 1974 and was then elected to the state Senate in 1980. He served in the Senate until 2005, when he retired because of term limits. In 1989, he was elected as as President Pro Tem, the top leadership role in the legislature, and he held that position for eight years during the administration of Gov. Mel Carnahan. Funeral arrangements are pending.