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Re: Pachycephalosaur nasal airflow



Another news release with good videos:

http://phys.org/news/2014-10-dinosaur-noses-cooled-brain.html

On Tue, Oct 14, 2014 at 1:45 PM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
>
> A news story:
>
> http://news.discovery.com/animals/dinosaurs/dinosaurs-were-heavy-wet-breathers-141014.htm
>
> On Tue, Oct 14, 2014 at 8:10 AM, Ben Creisler <bcreisler@gmail.com> wrote:
>> Ben Creisler
>> bcreisler@gmail.com
>>
>> A new paper:
>>
>> Jason M. Bourke, WM. Ruger Porter, Ryan C. Ridgely, Tyler R. Lyson,
>> Emma R. Schachner, Phil R. Bell and Lawrence M. Witmer (2014)
>> Breathing Life Into Dinosaurs: Tackling Challenges of Soft-Tissue
>> Restoration and Nasal Airflow in Extinct Species.
>> The Anatomical Record 297(11): 2148–2186
>> Special Issue: Special Issue The Vertebrate Nose: Evolution,
>> Structure, and Function
>> DOI: 10.1002/ar.23046
>> http://onlinelibrary.wiley.com/doi/10.1002/ar.23046/abstract
>>
>>
>>
>>
>> The nasal region plays a key role in sensory, thermal, and respiratory
>> physiology, but exploring its evolution is hampered by a lack of
>> preservation of soft-tissue structures in extinct vertebrates. As a
>> test case, we investigated members of the “bony-headed” ornithischian
>> dinosaur clade Pachycephalosauridae (particularly Stegoceras validum)
>> because of their small body size (which mitigated allometric concerns)
>> and their tendency to preserve nasal soft tissues within their
>> hypermineralized skulls. Hypermineralization directly preserved
>> portions of the olfactory turbinates along with an internal nasal
>> ridge that we regard as potentially an osteological correlate for
>> respiratory conchae. Fossil specimens were CT-scanned, and nasal
>> cavities were segmented and restored. Soft-tissue reconstruction of
>> the nasal capsule was functionally tested in a virtual environment
>> using computational fluid dynamics by running air through multiple
>> models differing in nasal soft-tissue conformation: a bony-bounded
>> model (i.e., skull without soft tissue) and then models with soft
>> tissues added, such as a paranasal septum, a scrolled concha, a
>> branched concha, and a model combining the paranasal septum with a
>> concha. Deviations in fluid flow in comparison to a phylogenetically
>> constrained sample of extant diapsids were used as indicators of
>> missing soft tissue. Models that restored aspects of airflow found in
>> extant diapsids, such as appreciable airflow in the olfactory chamber,
>> were judged as more likely. The model with a branched concha produced
>> airflow patterns closest to those of extant diapsids. These results
>> from both paleontological observation and airflow modeling indicate
>> that S. validum and other pachycephalosaurids could have had both
>> olfactory and respiratory conchae. Although respiratory conchae have
>> been linked to endothermy, such conclusions require caution in that
>> our re-evaluation of the reptilian nasal apparatus indicates that
>> respiratory conchae may be more widespread than originally thought,
>> and other functions, such as selective brain temperature regulation,
>> could be important.