Evidence for the presence of nasal salt glands in the Hadrosauridae (Ornithischia)

Abstract

The subcutaneous nasal glands of some Recent reptiles and birds, mainly secreting salts of sodium and potassium, are sometimes contained within depressions in the skull; they lie above or in front of the orbit. Similar preorbital or circumnarial depressions in the skull of certain ornithischian dinosaurs (Hadrosaurinae) and lateral chambers within the hollow crests of others (Lambeosaurinae) may therefore have contained similar glands; ‘troughs’ in the premaxillae below the external nares would have prevented hypertonic solutions from entering the mouth. In the genus Parasaurolophus the nasal bones appear to have migrated into the distal part of the crest. The nature of the sediments and of the flora of the Late Cretaceous of north-western North America suggests that salt glands would have been essential to hadrosaurs, which fed on harsh terrestrial vegetation growing in a salt-rich environment.