Morphological convergence in ‘river dolphin’ skulls: a disparate grouping justified
- Published
- Accepted
- Subject Areas
- Evolutionary Studies, Taxonomy, Zoology
- Keywords
- Convergent evolution, Geometric Morphometrics, Inia geoffrensis, Lipotes vexillifer, Pontoporia blainvillei, Platanista gangetica, Mandible, Skull
- Copyright
- © 2017 Page et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2017. Morphological convergence in ‘river dolphin’ skulls: a disparate grouping justified. PeerJ Preprints 5:e3222v1 https://doi.org/10.7287/peerj.preprints.3222v1
Abstract
Convergent evolution can provide insights into the predictability of, and constraints on, the evolution of biodiversity. One striking example of convergence is seen in the ‘river dolphins’. The four dolphin genera that make up the ‘river dolphins’ (Inia geoffrensis, Pontoporia blainvillei, Platanista gangetica and Lipotes vexillifer) do not represent a monophyletic group, despite being very similar in morphology. This has led many to using the ‘river dolphins’ as an example of convergent evolution. However, these morphological similarities have never been quantified. We investigate whether the skulls of the four ‘river dolphin’ genera are convergent when compared to other toothed dolphin taxa. We use geometric morphometrics to uncover shape variation in the skulls of the ‘river dolphins’ and then apply a number of phylogenetic techniques to test for convergence. We find significant convergence in the skull morphology of the ‘river dolphins’. The four genera seem to have experienced evolution in the same direction, leading to a convergent morphotype characterised by elongation of skull features. The cause of this morphological convergence remains unclear, but our results support hypotheses of shared feeding mode or diet and thus provide the foundation for future work into convergence within the Odontoceti.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Supplemental Information S1
Supplemental Information document number 1, detailing further information on the specimens used and their accession numbers. Table S1.
Supplemental Information S2
Supplemental Information document number 2, detailing further information on landmark identification and error analyses. Tables S2-S5.
Supplemental Information S3
Supplemental Information document number 3, detailing further results of principal component analyses, in addition to results of tests for convergence at both the species and specimen level. Tables S6-S10.