What is "sumugan"

Šumugan (Shumugan, Šumuqan, Šakkan, Šamkan, Amakandu) is, in Sumerian mythology a god of the river plains. In creation myth he is given charge by the god Enki over the flat alluvial lands of southern Mesopotamia. He is also known as a god of cattle who dwells in the court of the underworld goddess Ereshkigal. Šumugan's father is Shamash, the sun god, and he may derive from the similar god Lahar.