{{short description|American paleontologist}}

{{Self-published|date=June 2025}} '''John A. Ruben''' is a researcher in Zoology and Vertebrate paleontology at the Oregon State University in Corvallis, United States. Much of his published research is focused on studying the respiratory system in birds, in order to contradict the theory of theropodan ancestry of birds, as well as their metabolism.

==Research== Ruben has questioned for many years the theory that birds descend from small carnivorous dinosaurs of suborder Theropoda. He suggest theropods had a diaphragma driven respiratory system which could not have evolved into the complex air sacs in birds (but the presence of air sacs in saurischian dinosaurs has been demonstrated by highly pneumatic fossil bones of e.g. ''Aerosteon'' and ''Tataouinea''). While some have claimed Ruben's research to be flawed, his papers have, nevertheless, appeared in highly regarded, heavily peer-reviewed journals such as Science, Nature and the Journal of Morphology. He has done some research on the dinosaurs ''Scipionyx''<ref>Ruben. J.A, et al. ''Pulmonary Function and Metabolic Physiology of Theropod Dinosaurs'', p. 514-516.</ref> and ''Sinosauropteryx'',<ref>Gibbons.A. ''Lung Fossils Suggests Dinos Breathed in Cold Blood'', ''Science'', 14 November 1997.</ref><ref>{{cite journal|title=Lung Fossils Suggest Dinos Breathed in Cold Blood|first=Ann|last=Gibbons|date=14 November 1997|journal=Science|volume=278|issue=5341|pages=1229–1230|doi=10.1126/science.278.5341.1229a|s2cid=82006496}}</ref> from which he gives his arguments. Ruben also took part in the 2009 discovery of a close correlation between the immobilized thighbone and complex respiratory systems in birds.<ref>Quick et al. ''Cardio-pulmonary anatomy in theropod dinosaurs: Implications from extant archosaurs'', ''Journal of Morphology'' 2009.</ref><ref>[https://www.sciencedaily.com/releases/2009/06/090609092055.htm Quick et al. Ibid, ''www.sciencedaily.com''.]</ref>

Research on the fossil animal ''Microraptor'' has also led Ruben to suggest that Dromaeosauridae, for a long time regarded as feathered dinosaurs, actually represent flightless descendants of older birds,<ref>{{cite web|url=https://www.sciencedaily.com/releases/2010/02/100209183335.htm|title=Bird-from-dinosaur theory of evolution challenged: Was it the other way around?|publisher=}}</ref> as he said: "We think the evidence is showing that these animals which are usually considered dinosaurs were actually descended from birds, not the other way around".<ref>This statement is somewhat incorrect, as Dromaeosauridae are not believed to be the ancestors of birds, but a close sister taxon to them.</ref> Ruben sees it more possible that perhaps a creature like the diapsid reptile ''Longisquama'' represents the ancestor to birds.<ref>[http://oregonstate.edu/dept/ncs/newsarch/2000/Jun00/birds.htm John Ruben about ''Longisquama''.] {{webarchive|url=https://web.archive.org/web/20051226211815/http://oregonstate.edu/dept/ncs/newsarch/2000/Jun00/birds.htm |date=2005-12-26 }}</ref>

== References. == {{reflist}}

==External links== * [http://people.oregonstate.edu/~rubenj/index.htm Ruben's profile at Oregon State University's homepage].

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{{DEFAULTSORT:Ruben, John}} Category:21st-century American zoologists Category:American paleontologists Category:Oregon State University faculty Category:Living people Category:Year of birth missing (living people)