VESTIGIAL DUCT. “Ductus venosus → ligamentum venosum. The ductus venosus closes shortly after birth (functionally, with full structural closure occurring days later); its fibrous remnant is known as the ligamentum venosum. This is often continuous with the round ligament of the liver, also known as the ligamentum teres hepatis.”
https://evolution-outreach.springeropen.com/articles/10.1186/s12052-014-0012-5