Details:

Journal Title:
Journal of Morphology
Personal Author:
Popp, Meagan ; White, Connor F. ; Bernal, Diego ; Wainwright, Dylan K. ; Lauder, George V.
Popp, Meagan ; White, Connor F. ; Bernal, Diego ; Wainwright, Dylan K. ; Lauder, George V. Less -
NOAA Program & Office:
NMFS (National Marine Fisheries Service)
Description:
Shark skin denticles (scales) are diverse in morphology both among species and across the body of single individuals, although the function of this diversity is poorly understood. The extremely elongate and highly flexible tail of thresher sharks provides an opportunity to characterize gradients in denticle surface characteristics along the length of the tail and assess correlations between denticle morphology and tail kinematics. We measured denticle morphology on the caudal fin of three mature and two embryo common thresher sharks (Alopias vulpinus), and we compared thresher tail denticles to those of eleven other shark species. Using surface profilometry, we quantified 3D‐denticle patterning and texture along the tail of threshers (27 regions in adults, and 16 regions in embryos). We report that tails of thresher embryos have a membrane that covers the denticles and reduces surface roughness. In mature thresher tails, surfaces have an average roughness of 5.6 μm which is smoother than some other pelagic shark species, but similar in roughness to blacktip, porbeagle, and bonnethead shark tails. There is no gradient down the tail in roughness for the middle or trailing edge regions and hence no correlation with kinematic amplitude or inferred magnitude of flow separation along the tail during locomotion. Along the length of the tail there is a leading‐to‐trailing‐edge gradient with larger leading edge denticles that lack ridges (average roughness = 9.6 μm), and smaller trailing edge denticles with 5 ridges (average roughness = 5.7 μm). Thresher shark tails have many missing denticles visible as gaps in the surface, and we present evidence that these denticles are being replaced by new denticles that emerge from the skin below.
Keywords:
[+]
Animal Science And Zoology Developmental Biology
Source:
Journal of Morphology, 281(8), 938-955
DOI:
https://doi.org/10.1002/jmor.21222
ISSN:
0362-2525;1097-4687;
Format:
PDF
Publisher:
Wiley
Document Type:
Journal Article
Funding:
Grant no. NA16NMF4270231
Rights Information:
Accepted Manuscript
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:f4512e34f55622ea1d09873aefb033b1be88c0cd08178d4ac85e18e8d9a3b94a
Download URL:
https://repository.library.noaa.gov/view/noaa/57173/noaa_57173_DS1.pdf
File Type:

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