[MARMAM] Recent Paper on Comparative Pinniped Whisker Morphology

Chris Marshall marshalc at tamug.edu
Mon Apr 9 09:49:36 PDT 2012


Dear Colleagues,

I'd like to draw your attention to a recent paper published by Ginter, DeWitt, Fish, and Marshall in PLoS ONE on the comparative morphology of pinniped whiskers.  This work fuses traditional morphometrics with geometric morphometrics to provide new comparative data that demonstrates species specific differences in the morphology of pinniped hair shafts of their vibrissae (whiskers).

Ginter CC, DeWitt TJ, Fish FE, Marshall CD (2012) Fused Traditional and Geometric Morphometrics Demonstrate Pinniped Whisker Diversity. PLoS ONE 7(4): e34481. doi:10.1371/journal.pone.0034481

Abstract

Vibrissae (whiskers) are important components of the mammalian tactile sensory system, and primarily function as detectors of vibrotactile information from the environment. Pinnipeds possess the largest vibrissae among mammals and their vibrissal hair shafts demonstrate a diversity of shapes. The vibrissae of most phocid seals exhibit a beaded morphology with repeating sequences of crests and troughs along their length. However, there are few detailed analyses of pinniped vibrissal morphology, and these are limited to a few species. Therefore, we comparatively characterized differences in vibrissal hair shaft morphologies among phocid species with a beaded profile, phocid species with a smooth profile, and otariids with a smooth profile using traditional and geometric morphometric methods. Traditional morphometric measurements (peak-to- peak distance, crest width, trough width and total length) were collected using digital photographs. Elliptic Fourier analysis (geometric morphometrics) was used to quantify the outlines of whole vibrissae. The traditional and geometric morphometric datasets were subsequently combined by mathematically scaling each to true rank, followed by a single eigendecomposition. Quadratic discriminant function analysis demonstrated that 79.3, 97.8 and 100% of individuals could be correctly classified to their species based on vibrissal shape variables in the traditional, geometric and combined morphometric analyses, respectively. Phocids with beaded vibrissae, phocids with smooth vibrissae, and otariids each occupied distinct morphospace in the geometric morphometric and combined data analyses. Otariids split into two groups in the geometric morphometric analysis and gray seals appeared intermediate between beaded- and smooth-whiskered species in the traditional and combined analyses. Vibrissal hair shafts modulate the transduction of environmental stimuli to the mechanoreceptors in the follicle-sinus complex (F-SC), which results in vibrotactile reception, but it is currently unclear how the diversity of shapes affects environmental signal modulation.

Since PLoS ONE is an open access journal, PDF's of the paper should be easily obtained through their website.

Thanks,

Christopher Marshall

------------------------------
Christopher D. Marshall, Ph.D.
Associate Professor
Department of Marine Biology, and Wildlife and Fisheries Sciences
200 Seawolf Parkway
Building 3029, Room 253
Texas A&M University
Galveston, Texas 77553
Phone: (409) 740-4884
Fax: (409) 740-5001
Email: marshalc at tamug.edu<mailto:marshalc at tamug.edu>
(please note the difference in the spelling of my last name)
Website: www.marinebiology.edu/Marshall
--
Great things are not done by impulse, but by a series of small things
brought together.
- Vincent van Gogh





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