Lying on a vertical rockface, the specimen required a difficult excavation process, involving the removal of over 300 cubic metres of mineral and use of large equipment.

[2] The significance of the find was immediately recognized, being the oldest hadrosaur known from the Europe and the most complete large dinosaur skeleton found on the continent since the 19th century discovery of Iguanodon remains at Bernissart, Belgium.

Based on the presence of foraminiferan Murciella cuvillieri and alligatoroid Acynodon, in addition to geologic data, the hadrosaur fossil dated to the Campanian-Maastrichtian boundary, around 70 million years ago.,[3] an age recently re-evaluated by more recent studies [1] to 81.5-80.5 million years ago and to the Calcare di Aurisina formation.

In 2004, a book on dinosaurs in Italy by Cristiano Dal Sasso was published which dedicated a chapter to the subject of the hadrosaurs from Trieste.

[3] "Bruno" was not prepared until 2019, at which point images were posted online and the specimen was publicly displayed at the Duino Castle through the winter of that year and 2020.

[3][5] Della Vacchia published an additional description of the species, focusing on its tail anatomy specifically, in 2020, which was mostly confuted in following studies.

[1] Although the holotype Antonio was initially thought to represent an adult,[3] it was later assessed to be a subadult individual based on the histology of its bones.

Bruno, which is 15–20% larger than Antonio, was found to be an adult, and it shows features related to maturity such as a more robust skull and stouter proportions.

In some ways the species more resembles earlier relatives like Iguanodon, such as in its general skull shape, possession of a supraorbital bone, and comparatively short neck.

[2] In 2021, Prieto-Márquez and Carrera Farias recovered Tethyshadros as the sister taxon to Fylax, in a derived position in the Hadrosauromorpha, making it one of the latest surviving non-hadrosaurid hadrosauromorphs.

Their cladogram is shown below:[7] Jeyawati Eolambia Protohadros Tanius Bactrosaurus Gilmoreosaurus Lophorhothon Penelopognathus Telmatosaurus Claosaurus Fylax Tethyshadros Plesiohadros Eotrachodon Hadrosauridae Chiarenza et al 2021 performed a phylogenetic analysis of Bruno.

[1] Jinzhousaurus Equijubus Sirindhorna Xuwulong Zuoyunlong Probactrosaurus Eolambia Yunganglong Jintasaurus Levnesovia Tanius Bactrosaurus Gilmoreosaurus Nanningosaurus Claosaurus Telmatosaurus Tethyshadros Eotrachodon Zhanghenglong Plesiohadros Adynomosaurus Nanyangosaurus Hadrosauridae