Tethyshadros, meaning “Tethys ocean thick lizard,” is a genus of hadrosaurid dinosaur from the Campanian-Maastrichtian ages of the Late Cretaceous Period (71 – 70 million years ago) from Italy. It was named and described by Italian paleontologist Fabio Marco Dalla Vecchia in 2009. The type species is T, insularis. The specific name means “insular” or “of the island.”
Tethyshadros is known from a mostly complete but crushed skeleton that was previously nicknamed “Antonio.” The specimen was believed to be about 5 or 6 years old when it died. It was discovered in the Villagio del Pescatore site in the Province of Trieste, near Duino Aurisina in the Liburnia Formation in April 1999. Since then, six more specimens have been found, one of them a skeleton that fell apart during removal.
Tethyshadros is only the second dinosaur genus to have been discovered in Italy. All fossils of Tethyshadros are kept at the Museum of Natural History in Trieste (Museo Civico di Storia Naturale di Trieste). The fossils are the property of the Italian State.
Tethyshadros was a relatively small dinosaur at about 13 feet long and weighed about 770 pounds. The skull is relatively long and the neck and tail are short. The legs are long, especially the shin bones. These proportions, along with a reduction of the number of fingers, are seen as an adaptation for bipedal running.
Tethyshadros shows a mix of primitive and derived traits. Analysis indicates it was closely related to Telmatosaurus. According to Dalla Vecchia, the presence of Tethyshadros on a European island is caused by a radiation of primitive hadrosaurids, island-hopping from Asia. He rejects the possibility of isolated evolution from earlier European hadrosaurids or descendants of American hadrosaurs.