MEXICO CITY — A longtime senior chief of the Sinaloa cartel, Ismael Zambada Garcia, or “El Mayo,” and a son of famed drug lord Joaquin “El Chapo” Guzman had been taken into custody by U.S. authorities in Texas, based on senior Mexican and U.S. officers. It was a serious blow to the Sinaloa federation, a world drug-trafficking syndicate that has despatched tons of cocaine, heroin, fentanyl and different medicine to the US.