Yangchuanosaurus zigongensis ("from Zigong") was originally named Szechuanosaurus zigongensis by Gao in 1993 based on an almost complete skeleton (holotype ZDM 9011, plus ZDM 9012, ZDM 9013 and ZDM 9014) from the Dashanpu Dinosaur Quarry of Zigong, Sichuan, then he named it again in a 1998 paper as if it was an all new critter! Chure 2001 believed that these fossils belonged to Szechuanoraptor dongi—a name he coined in 2001 for remnants which were originally known as Szechuanosaurus "yandonensis". Lacking similarities and being from the much older Middle Jurassic lower Shaximiao (Xiashaximiao) Formation, Matt Carrano used these remains to anchor a new species of Yangchuanosaurus — Yangchuanosaurus zigongensis — in 2012. This is the only other species of Yangchuanosaurus that is considered valid. Yangchuanosaurus hepingensis ("from Heping") was discovered in the Upper Shaximiao (Shangshaximiao) Formation about 1 km north of the Zigong Train Station by He Geyin, Wang Fucheng and other farmers from Heping in February of 1985. It was named by Gao Yuhui in 1992 but became a second species of Sinraptor—Sinraptor hepingensis—when Currie and Zhao named Sinraptor dongi in 1994. In 1999, Gao figured that by synonomising Sinraptor with Yangchuanosaurus not only would he get his Yangchuanosaurus hepingensis back he would also add a fourth species—Yangchuanosaurus dongi—to the Yangchuanosaurus stable. Unfortunately (for him!) almost no-one took his revenge-sinking seriously. In 2009, Lida Xing re-described a shoulder blade of the holotype (ZDM 0024) that he surmised had been damaged in a violent collision, perhaps with the swinging tail club of the sauropod Mamenchisaurus hochuanensis. Yangchuanosaurus magnus ("Great") was named by Dong, Zhou, and Zhang in 1983, simply for being the largest specimen of Yangchuanosaurus ever discovered (the skull measures 111 cm long and 65 cm high). According to Carrano et al, size is pretty much the only difference between Yangchuanosaurus magnus and Yangchuanosaurus shangyouensis, and no grounds to keep them separate, which is what most paleontologists have always thought. It's based on #CV00216 (a weathered skull and partial skeleton consisting mainly of vertebrae and hip bones but not much in the way of limbs) that was discovered while digging foundations for the Hongjiang Machine Factory in Yongchuan in September of 1973, and was excavated by Li Xuanmin, Zhou Shiwu, and Lan Dongyao of the Chungking Museum of Natural History. Yangchuanosaurus shangyouensis:
Yangchuanosaurus magnus (Dong, Zhou & Zhang, 1983)
Szechuanosaurus yandonensis (Dong et al., 1978)
Szechuanoraptor dongi (Chure, 2001) Yangchuanosaurus zigongensis:
Szechuanosaurus zigongensis (Gao, 1993)