Enables hyaluronan synthase activity. Involved in extracellular matrix assembly and extracellular polysaccharide biosynthetic process. Acts upstream of or within hyaluronan biosynthetic process. Located in cytoplasm and membrane. Is expressed in several structures, including alimentary system epithelium; face; gonad; heart; and skin. Orthologous to human HAS1 (hyaluronan synthase 1). [provided by Alliance of Genome Resources, Apr 2022]