It is known from GMPKU-P-1033, a partial skeleton recovered from the Upper Member of the Guanling Formation of Yangjuan village, Xinmin area; this rock unit dates to the Pelsonian substage of the Anisian stage.
The type species is known from the holotype IVPP V6064, a nearly complete skull which was collected in the Zhuengeerqi locality, from the upper Heshanggou Formation (Olenekian and earliest Anisian stages), Ordos Basin.
Sinosaurosphargis is an extinct genus of non-sauropterygian marine reptile known from the lower Middle Triassic (Pelsonian substage, Anisian stage) of Yangmazhai, Luoping County of Yunnan Province, southwestern China.