Nostril Position in Dinosaurs and Other Vertebrates and Its Significance for Nasal Function Lawrence M. Witmer

Taxa comprising the extant sample are listed below. Taxa were selected to ensure as broad a sample as possible and to estimate the primitive condition in each clade. In most cases, a single specimen per species was sampled. Multiple specimens were sampled for some species to assess intraspecific variation (which was negligible), and the number per species is indicated. Squamata-Iguanidae (Iguana iguana - 2); Agamidae (Uromastyx aegypticus - 2, Hydrosaurus amboinensis); Gekkonidae (Gekko gecko); Varanidae (Varanus dumerili, V. exanthematicus, V. griseus). Crocodylia-Alligatoridae (Alligator mississippiensis - 2). Aves-Ratitae: Rheidae (Pterocnemia pennata, Rhea sp.); Casuariidae (Dromaius novaehollandiae); Struthionidae (Struthio camelus); Galliformes: Phasianidae (Gallus gallus - 3, Phasianus colchicus - 2, Meleagris gallopavo); Anseriformes: Anatidae (Anser anser - 5, Anas platyrhynchos - 3); Charadriiformes: Alcidae (Fratercula cirrhata), Laridae (Larus delawarensis - 3); Sphenisciformes: Spheniscidae (Spheniscus demersus, Pygoscelis adeliae); Procellariiformes: Procellariidae (Fulmarus glacialis); Gruiformes: Rallidae (Fulica americana - 2); Columbiformes: Columbidae (Zenaida macroura, Streptopelia dacaocta); Pelecaniformes: Phalacrocoracidae (Phalacrocorax auritus); Strigiformes: Strigidae (Otus asio - 2, Bubo virginianus); Ciconiiformes: Ardeidae (Ardea herodias), Cathartidae (Cathartes aura), Threskiornithidae (Threskiornithidae indet.); Falconiformes: Accipitridae (Buteo jamaicensis, Buteo lineatus, Accipiter cooperii); Psittaciformes: Psittacidae (Melopsittacus undulates); Cuculiformes: Cuculidae (Cuculidae indet.); Coraciiformes: Cerylidae (Megaceryle alcyon); Piciformes: Picidae (Dendrocopus pubescens, Hylatomus pileatus); Passeriformes: Icteridae (Quiscalus quiscula), Fringillidae (Cardinalis cardinalis), Corvidae (Cynanocitta cristata - 2), Muscicapidae-Turdidae (Turdus migratorius, Catharus ustulatus), Sturnidae (Sturnus vulgaris). Data on turtles and mammals were collected from the literature, numerous dried skulls, and dissection notes and accumulated experience; the stereoradiographic techniques were not used for these clades partly because turtles and mammals are less relevant for inferences about dinosaurs but mostly because the narial anatomy of turtles and mammals clearly dictates the rostral position of the fleshy nostril relative to the bony nostril.