"M. guangyuanensis" was briefly mentioned by Zhang, Li, and Zeng in 1998 with the description of "M. jingyanensis," but no details are given. Li and Cai considered it a "nomen nudum". Wang and colleagues considered it undiagnostic in 2019. "M. yunnanensis was" described by Fang and colleagues in 2004, from the Anning Formation in the Sichuan Basin, Yunnan. The type specimen consisted of disarticulated forelimb, hindlimb, and pelvic material. Wang and colleagues questioned the assignment to "Mamenchisaurus" in 2019. "M. yaochinensis" is a "nomen nudum".