 Fossils of "D. vietnamica" have been found in the Eifelian of China (Nandan Formation, Luofu, Nandan County, Guangxi Province , and Hunan Province); and in the Pragian of Vietnam (Song Hiem, Mia Le Beds ).Fossils of "D. ductifrons" have been found in the Famennian of the United Kingdom, Germany (Eskesberg, Nehden, Varresbeck, all near Wupperthal), Poland (near Psiarnia, in the Southern part of the Holy Cross Mountains ), and the Western Urals in Russia.All phacopids were probably marine bottom-dwellers.