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Evolutionary drivers of morphological differentiation among three bottlenose dolphin lineages, Tursiops spp. (Delphinidae), in the northwest Indian Ocean utilizing linear and geometric morphometric techniques

Gray, Howard; van Waerebeek, Koen; Owen, Joseph; Collins, Tim; Minton, Gianna; Ponnampalam, Louisa; Willson, Andrew; Baldwin, Robert; Hoelzel, A Rus

Evolutionary drivers of morphological differentiation among three bottlenose dolphin lineages, Tursiops spp. (Delphinidae), in the northwest Indian Ocean utilizing linear and geometric morphometric techniques Thumbnail


Authors

Howard Gray

Koen van Waerebeek

Joseph Owen

Tim Collins

Gianna Minton

Louisa Ponnampalam

Andrew Willson

Robert Baldwin



Abstract

Local adaptation and adaptive radiations are typically associated with phenotypic variation suited to alternative environments. In the marine environment, the nature of relevant ecological or environmental transitions is poorly understood, especially for highly mobile species. Here we compare three genetic lineages in the genus Tursiops (bottlenose dolphins), using linear measurements and geometric morphometric techniques, in the context of environmental variation in the northwest Indian Ocean. Cranial morphology was clearly differentiated comparing Tursiops truncatus and Tursiops aduncus, while a recently discovered genetic lineage, found in the Arabian Sea, was morphologically most similar to T. aduncus from the same region, but distinct for various measures, particularly metrics associated with the lateral dimension of the skull. The extent of divergence between T. truncatus and T. aduncus compared to differences between the T. aduncus lineages is consistent with the recent phylogeny for these species. Therefore, with the corroboration of genetic and morphological inference, we propose two conservation units of T. aduncus be recognized in the region at a sub-specific level so that their conservation can be managed effectively. We consider possible evolutionary mechanisms associated with regional habitat characteristics and the exploitation of distinct prey resources.

Citation

Gray, H., van Waerebeek, K., Owen, J., Collins, T., Minton, G., Ponnampalam, L., …Hoelzel, A. R. (2022). Evolutionary drivers of morphological differentiation among three bottlenose dolphin lineages, Tursiops spp. (Delphinidae), in the northwest Indian Ocean utilizing linear and geometric morphometric techniques. Biological Journal of the Linnean Society, 135(3), 610-629. https://doi.org/10.1093/biolinnean/blab133

Journal Article Type Article
Acceptance Date Aug 26, 2021
Online Publication Date Dec 31, 2021
Publication Date 2022-03
Deposit Date Jul 15, 2022
Publicly Available Date Mar 29, 2024
Journal Biological Journal of the Linnean Society
Print ISSN 0024-4066
Electronic ISSN 1095-8312
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 135
Issue 3
Pages 610-629
DOI https://doi.org/10.1093/biolinnean/blab133

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Copyright Statement
This is a pre-copyedited, author-produced version of an article accepted for publication in Biological Journal of the Linnean Society following peer review. The version of record: Gray, Howard, van Waerebeek, Koen, Owen, Joseph, Collins, Tim, Minton, Gianna, Ponnampalam, Louisa, Willson, Andrew, Baldwin, Robert & Hoelzel, A Rus (2022). Evolutionary drivers of morphological differentiation among three bottlenose dolphin lineages, Tursiops spp. (Delphinidae), in the northwest Indian Ocean utilizing linear and geometric morphometric techniques. Biological Journal of the Linnean Society 135(3): 610-629 is available online at: https://doi.org/10.1093/biolinnean/blab133





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