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In contradistinction to these prevailing theories, here we show that unidirectional flow is present in the lungs of the green iguana, an ectothermic animal with low aerobic capacity, no intrapulmonary bronchus, and no intercameral perforations. This discovery indicates a transformation in our understanding of the evolution of the vertebrate respiratory system is needed.<\/jats:p>","DOI":"10.1073\/pnas.1405088111","type":"journal-article","created":{"date-parts":[[2014,11,20]],"date-time":"2014-11-20T03:43:24Z","timestamp":1416455004000},"page":"17218-17223","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":57,"title":["New insight into the evolution of the vertebrate respiratory system and the discovery of unidirectional airflow in iguana lungs"],"prefix":"10.1073","volume":"111","author":[{"given":"Robert L.","family":"Cieri","sequence":"first","affiliation":[{"name":"Department of Biology, University of Utah, Salt Lake City, UT 84112; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brent A.","family":"Craven","sequence":"additional","affiliation":[{"name":"Applied Research Laboratory, Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emma R.","family":"Schachner","sequence":"additional","affiliation":[{"name":"Department of Biology, University of Utah, Salt Lake City, UT 84112; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C. 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