The Penobscot Nation chief and his two adult sons have pleaded not guilty to misdemeanor charges of assault and disorderly conduct stemming from a January parking lot fracas in Bangor with another tribal council leader. Chief Kirk Francis, 48, of Bangor and his sons Kirk Francis Jr., 27, of Westbrook and Tannar Francis, 25, of Farmington allegedly got into a fight with Robert Dana, 51, of Indian Island in the parking lot of a Bangor bar. Dana also has pleaded not guilty to the same charges. The dispute stemmed from long-simmering tensions between Francis and Dana, a member of the Penobscot Nation’s 12-person Tribal Council, over tribal business, Dana’s wife, Tonia Dana, 45, of Indian Island said last month.