Nostril position in dinosaurs and other vertebrates and its significance for nasal function

Many dinosaurs have enormous and complicated bony nasal apertures. Function al interpretation requires knowledge of the Location of the external openin g in the skin. Traditionally, the fleshy nostril of dinosaurs has been plac ed in the back of the bony opening, but studies of extant dinosaur relative s suggest that it is located far forward. Narial blood supply and cavernous tissue corroborate the rostra[ position in dinosaurs. A rostra[ nostril wa s, and remains, a virtually invariant rule of construction among Amniota, w hich has consequences for (I) nasal airstreaming, and hence various physiol ogical parameters, and (ii) the collection of behaviorally relevant circumo ral odorants.