The origin of dinosaurs can be traced back to the Triassic Period, about 200 million years ago. After about 100 million years of evolution, dinosaurs in the Cretaceous Period showed immense diversity. There were numerous species, with some adapting to vastly different environments and evolving specialized diets.Following the release of the “Dinosaurs Souvenir Sheet” in 2025, Chunghwa Post has issued a new souvenir sheet featuring four types of saurischian dinosaurs. This sheet contains four stamps, each with a denomination of NT$15. A brief description of the designs follows:1. Spinosaurus (NT$15): A member of the Spinosauridae family, it features a long, narrow head and conical teeth. Its strong forelimbs are equipped with giant claws, indicating its habitat of riverbanks or waterside, and adaptation of preying on fish. Its massive body and eye-catching dorsal sail are its salient characteristics.2. Xixianykus (NT$15): A member of the Alvarezsauridae family, it had exceptionally short forelimbs and a compact, agile body built for speed.3. Halszkaraptor (NT$15): Evolved from small, agile carnivorous dinosaurs such as dromaeosaurids or troodontids, it retained an enlarged claw on its second toe. Morphologically, it was similar to ducks and other modern waterfowl, and it is hypothesized that they had webbed feet for swimming.4. Mononykus (NT$15): A member of the Alvarezsauridae family, it featured a large thumb. Paleontologists hypothesize that they used these claws to dig into ant nests and were particularly adapted to feeding on termites, occupying a unique ecological niche among dinosaurs.To purchase postage stamps, please go directly to the post office branches, Postal Museum or order on line at https://stamp.post.gov.tw.