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Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)

Dissertation (MSc (Zoology))--University of Pretoria, 2014.

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Other Authors: Bester, Marthan Nieuwoudt
Format: Thesis
Language:English
Published: University of Pretoria 2022
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access_status_str Open Access
author2 Bester, Marthan Nieuwoudt
author_browse Bester, Marthan Nieuwoudt
author_facet Bester, Marthan Nieuwoudt
collection Thesis
dc_rights_str_mv © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
description Dissertation (MSc (Zoology))--University of Pretoria, 2014.
format Thesis
id oai:repository.up.ac.za:2263/84067
institution University of Pretoria (South Africa)
language English
last_indexed 2026-06-10T12:39:48.717Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository
publishDate 2022
publishDateRange 2022
publishDateSort 2022
publisher University of Pretoria
publisherStr University of Pretoria
record_format dspace
source_str UPSpace — University of Pretoria Institutional Repository
spelling oai:repository.up.ac.za:2263/84067 Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis) Bester, Marthan Nieuwoudt pjndebruyn@zoology.up.ac.za De Bruyn, P.J. Nico Moshobane, Moleseng Claude Digital morphometrics Cranial morphology Subantarctic Fur seal Marion Island Gough Island Photogrammetry 3D Modelling Geographical variation Photomodeler scanner® UCTD Dissertation (MSc (Zoology))--University of Pretoria, 2014. Craniometrics is a very reliable and effective tool for studying the difference in animal morphology. Previously, traditional craniometrics were conducted with the aid of calipers in two dimensional format (2D). Such discounting of actual three-dimensional 3D form may result in loss of some relevant and critical information leading to compromised and unreliable results for studies such as population variation analysis of morphology. The employment of 3D photogrammetry allows a close to complete representation of the physical dimensions of a specimen. The use of photogrammetry in mammalogy concentrated on measuring of body size/mass, but little has been done on animal skull delineation through photogrammetry. This dissertation describes advances in morphometrics and 3D photogrammetry application in craniometrics, investigates the craniometric variation between closely related species (Arctocephalus gazella and A. tropicalis), and A. tropicalis interpopulation craniometrics between two geographically distinct populations, at Marion Island and Gough Island, using Photomodeler Scanner® (PMSc®) three-dimensional (3D) modelling software to produce accurate, high resolution 3D skull models. A total of 117 3D models were created from adult male fur seal crania, and 16 traditional measurements recorded, using specimens archived at the Port Elizabeth Museum, Bayworld, South Africa. Sixteen linear measurements, (8 caliper recordings and 8 3D recordings) were used for PMSc® methodology testing, 16 (A. gazella n= 8 and A. tropicalis n= 8) used for species cranial comparison and 85 (Marion Island n= 54 and Gough Island n= 31) used for interpopulation variation. The craniometric variations were analysed using the Statistica® v11 software package, StatSoft, Inc. The comparison between linear traditional caliper cranial measurements and 3D measurements produced significantly similar results, attesting to the accuracy of the PMSc® 3D model production. Photomodeler Scanner® therefore produces accurate and high resolution 3D models of skulls which allow 3D measurements. I predicted that PMSc® would detect the existing significant differences between the skulls of adult male A. gazella and A. tropicalis and modelled and compared their 3D models, and I further predicted that PMSc® would detect any existing differences between the skulls of A. tropicalis from Gough and Marion islands by comparison of their 3D models. The Gough Island and Marion Island A. tropicalis populations could not be discriminated based on linear 3D cranial I conclude that PMSc® is a reliable and effective tool for accurate and high resolution 3D modelling. The present study confirms previous findings and contributes additional evidence that suggests that adult A. tropicalis males from Gough Island and Marion Island cannot be discriminated based on linear measurements of craniometrics, and deviates from the Bergmanian rule as applied to large mammals. The present study, however, makes several noteworthy contributions to the use of PMSc® and 3D modelling in morphometrics. Taken together, these findings suggest a role for PMSc® 3D modelling in promoting accurate digitization of museum specimens and creation of online museum libraries. This research will serve as a baseline for future studies and usefulness of PMSc® in 3D morpho-volumetric measurements. Zoology and Entomology MSc (Zoology) Unrestricted 2022-02-18T08:45:04Z 2022-02-18T08:45:04Z 2014 2014-03 Dissertation * http://hdl.handle.net/2263/84067 en © 2021 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria
spellingShingle Digital morphometrics
Cranial morphology
Subantarctic Fur seal
Marion Island
Gough Island
Photogrammetry
3D Modelling
Geographical variation
Photomodeler scanner®
UCTD
Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title_full Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title_fullStr Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title_full_unstemmed Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title_short Inter-population craniometrics of adult male Subantarctic fur seals (Arctocephalus tropicalis)
title_sort inter population craniometrics of adult male subantarctic fur seals arctocephalus tropicalis
topic Digital morphometrics
Cranial morphology
Subantarctic Fur seal
Marion Island
Gough Island
Photogrammetry
3D Modelling
Geographical variation
Photomodeler scanner®
UCTD
url http://hdl.handle.net/2263/84067