the fossil assemblage in which "diandongosuchus" was found bears many similarities to that of european fossil localities such as monte san giorgio. both include marine reptiles like thallatosaurs and nothosaurs and probably represented environments along the northern shorelines of the tethys ocean. no marine archosaurs like "diandongosuchus" and "qianosuchus" are known from europe, although the pseudosuchian "ticinosuchus" from monte san giorgio was probably adapted to life along the shorelines of the tethys. in the analyses of li "et al." (2012) and nesbitt (2011), "ticinosuchus" is either the most basal member of a clade called loricata which is the sister taxon of poposauroidea, or the sister taxon of paracrocodylomorpha which includes both loricata and poposauroidea. although "ticinosuchus" and "diandongosuchus" were initially believed to have been very closely related basal paracrocodylomorphs, this hypothesis is invalidated if "diandongosuchus" is a phytosaur as other studies have shown.