TitleLung structure and ventilation in theropod dinosaurs and early birds
Publication TypeJournal Article
Year of Publication1997
AuthorsRuben, J, Jones, TD, Geist, NR, Hillenius, WJ
JournalScience
Volume278
Pagination1267-1270
Type of ArticleJournal Article
ISSN0036-8075
Abstract

Reptiles and birds possess septate lungs rather than the alveolar-style lungs of mammals. The morphology of the unmodified, bellowslike septate lung restricts the maximum rates of respiratory gas exchange. Among taxa possessing septate lungs, only the modified avian flow-through lung is capable of the oxygen-carbon dioxide exchange rates that are typical of active endotherms. Paleontological and neontological evidence indicates that theropod dinosaurs possessed unmodified, bellowslike septate lungs that were ventilated with a crocodilelike hepatic-piston diaphragm, The earliest birds (Archaeopteryx and enantiornithines) also possessed unmodified septate lungs but lacked a hepatic-piston diaphragm mechanism. These data are consistent with an ectothermic status for theropod dinosaurs and early birds.

URL<Go to ISI>://WOS:A1997YG04300037
DOI10.1126/science.278.5341.1267