Re: [dinosaur] Lateral-line-like wind-detecting sensory organs on albertosaurine tyrannosaur dentaries? (free pdf)

[Dann Pigdon <dannj@alphalink.com.au>]

I imagine there'd have been another reason why large theropods would have 
needed to be able to gauge 
wind direction and speed accurately, other than being able to locate scented 
prey. Being a multi-tonne biped 
with a horizontal spine and long neck/tail would have made it high 
disadvantageous to be caught broadside 
by a strong gust of wind. Even if they didn't get blown over completely (which 
would have been disastrous itself),
the twisting forces on the ankle or knee joints might have caused injury. 
Quadrupeds can generally cope with 
an injured leg if need be, but a multi-tonne biped wouldn't have had that same 
degree of locomotional adaptability.

I especially pity the poor spinosaur that got caught in gusty conditions!


On Fri, Nov 3rd, 2017 at 11:30 AM, Ben Creisler <bcreisler@gmail.com> wrote:

> Bruce M. Rothschild &, Virginia Naples (2017)
> Apparent sixth sense in theropod evolution: The making of a Cretaceous
> weathervane.
> PLoS ONE12(11): e0187064.
>
> Objective
> 
> Two separate and distinctive skills are necessary to find prey: Detection
> of its presence and determination of its location. Surface microscopy of
> the dentary of albertosaurines revealed a previously undescribed sensory
> modification, as will be described here. While dentary â??foraminaâ?? were
> previously thought to contain tactile sensory organs, the potential
> function of this theropod modification as a unique localizing system is
> explored in this study.
> 
> Method
> 
> Dentary surface perforations were examined by surface epi-illumination
> microscopy in tyrannosaurine and albertosaurine dinosaurs to characterize
> their anatomy. Fish lateral lines were examined as potentially comparable
> structures.
> 
> Result
> 
> In contrast to the subsurface vascular bifurcation noted in tyrannosaurines
> (which lack a lateral dentary surface groove), the area subjacent to the
> apertures in albertosaurine grooves has the appearance of an expanded
> chamber. That appearance seemed to be indistinguishable from the lateral
> line of fish.
> 
> Conclusion
> 
> Dentary groove apertures in certain tyrannosaurid lines (specifically
> albertosaurines) not only have a unique appearance, but one with
> significant functional and behavior implications. The appearance of the
> perforations in the dentary groove of albertosaurines mirrors that
> previously noted only with specialized neurologic structures accommodating
> derived sensory functions, as seen in the lateral line of fish. The
> possibility that this specialized morphology could also represent a unique
> function in albertosaurine theropods for interacting with the environment
> or facilitating prey acquisition cannot be ignored. It is suggested that
> these expanded chambers function in perceiving and aligning the body
> relative to the direction of wind, perhaps a Cretaceous analogue of the
> contemporary midwestern weathervane.

-- 
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 Dann Pigdon
 GIS Officer
 Melbourne, Australia
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