The first postage stamp featuring a prehistoric beast was a stamp from India (1951), celebrating the centenary of the Geological Survey of India it showed the reconstruction of the fossil elephant species Stegodon ganesca. In 1958 Cuba released a stamp dedicated to the naturalist Carlos de la Torre y Huerta (1858 - 1950), showing the giant sloth Megalocnus rodens.
In the same year China issued the very first stamp showing a dinosaur - the Chinese prosauropod Lufengosaurus. Belgium followed with the more prominent Iguanodon. From there dinosaurs will appear on postage stamps from Poland and San Marino (1965), Congo (1975), Germany (1977), Mongolia and Nicaragua (1987). The U.S. will dedicate four values to Pteranodon, Tyrannosaurus, Brontosaurus and Stegosaurus in 1989.
Fig.1.The small republic of San Marino issued a series of nine values, showing a Brontosaurus, Brachiosaurus, Pteranodon, Elasmosaurus, Tyrannosaurus, Stegosaurus, Thaumatosaurus, Iguanodon and Triceratops -mostly in dull colors (all images are in public domain).
Fig.3. Many editions of stamps with dinosaurs are intended for collectors - therefore often more aesthetic appealing as scientific accurate. Sometimes the motif is even simply copied from other artists or publications, like these two specimens, copies from the Saltopus by Jane Burton and the Tyrannosaurus by Doug Henderson.
THENIUS, E. & VAVRA, N. (1996): Fossilien im Volksglauben und im Alltag - Bedeutung und Verwendung vorzeitlicher Tier- und Pflanzenreste von der Steinzeit bis heute. Senckenberg-Buch 71, Waldemar Kramer Verlag - Frankfurt am Main: 179