Tsintaosaurus (/sɪntaʊˈsɔːrəs/; sic for the old transliteration "Tsingtao",[2] meaning "Qingdao lizard") is a genus of hadrosaurid dinosaur from China.

The crest, as preserved, consists of an about forty centimetres long process, protruding almost vertically from the top of the rear snout.

In 1990, David B. Weishampel and Jack Horner cast doubt on the presence of the crest, suggesting that it was actually a broken nasal bone from the top of the snout distorted upward by a crushing of the fossil.

[4] A new reconstruction in 2013, by Albert Prieto-Márquez and Jonathan Wagner and based on the identification of specimen IVPP V829, a praemaxilla, as a Tsintaosaurus element, came to the conclusion that the unicorn-like bone was just the rear part of a larger cranial crest that started from the tip of the snout.

This was rejected by Prieto-Márquez and Wagner who pointed out that the tube was closed at its lower end and that with lambeosaurines in general the air passages are located in a more forward position, the bony nostrils being completely enclosed by the praemaxillae.

They assumed that Tsintaosaurus would have had a standard lambeosaurine arrangement in the snout, the air, when inhaling, entering the skull through the paired pseudonares, the "fake nostrils" of the praemaxillae behind the upper beak.

From this they concluded that the entire airflow was likely separated, the common medium chamber probably being divided into a left and right section by a cartilaginous septum.

[5] The conclusion that the tubular structure in the rear nasal bones was not an air passage, forced Prieto-Márquez and Wagner to find an alternative explanation of its function.

They suggested that it would have served to lessen the weight of the crest, such a tube combining relative strength with a low bone mass.

The ascending branches of the praemaxillae have internal processes pointing to behind, below and slightly inside, dividing a shared chamber at the midline.

is indicated by this cladogram:[7] Aralosaurus Canardia Jaxartosaurus Tsintaosaurus Pararhabdodon Charonosaurus Parasaurolophus cyrtocristatus Parasaurolophus tubicen Parasaurolophus walkeri Lambeosaurus lambei Lambeosaurus magnicristatus Corythosaurus casuarius Corythosaurus intermedius "Hypacrosaurus" stebingeri Hypacrosaurus Olorotitan Arenysaurus Blasisaurus Magnapaulia Velafrons Amurosaurus Sahaliyania A study of dinosaur eggs in successive layers of the Wangshi Series of Shandong province, of which the Jingangkou Formation is the most recent layer, shows that the region was one of high dinosaur diversity and that the climate had become drier from the preceding Jiangjunding Formation.