Amphithalassius

{{short description|Genus of Dolichopodid flies from South Africa}}

{{Automatic taxobox

| taxon = Amphithalassius

| authority = Ulrich, 1991{{cite journal|last=Ulrich|first=H.|year=1991|title=Two new genera of parathalassiine-Iike flies from South Africa (Diptera, Empidoidea)|url=http://www.zobodat.at/pdf/Bonner-Zoologische-Beitraege_42_0187-0216.pdf|journal=Bonner zoologische Beiträge|volume=42|issue=2|pages=187–216}}

| type_species = Amphithalassius piricornis

| type_species_authority = Ulrich, 1991

}}

Amphithalassius is a genus of flies in the family Dolichopodidae. It is found along sandy sea coasts in South Africa. It contains two described species, and three undescribed species known only from females. It is closely related to Plesiothalassius.{{cite journal|last1=Cumming|first1=J.M.|last2=Brooks|first2=S.E.|year=2019|title=Phylogenetic analysis and preliminary classification of the Parathalassiinae (Diptera: Empidoidea: Dolichopodidae sensu lato)|url=https://www.mapress.com/j/zt/article/view/zootaxa.4648.1.5/29229|journal=Zootaxa|volume=4648|issue=1|pages=111–129|doi=10.11646/zootaxa.4648.1.5|doi-access=}}