Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines
- Published
- Accepted
- Subject Areas
- Anthropology, Biodiversity, Evolutionary Studies, Zoology
- Keywords
- Molar shape, platyrrhines, Geometric morphometric, phylogeny
- Copyright
- © 2016 Nova Delgado 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
- 2016. Morphometric variation of extant platyrrhine molars: taxonomic implications for fossil platyrrhines. PeerJ Preprints 4:e1796v2 https://doi.org/10.7287/peerj.preprints.1796v2
Abstract
The phylogenetic position of many fossil platyrrhines with respect to extant ones is not yet clear. Two main hypotheses have been proposed: the layered or successive radiations hypothesis suggests that Patagonian fossils are Middle Miocene stem platyrrhines lacking modern descendants, whereas the long lineage hypothesis argues for an evolutionary continuity of all fossil platyrrhines with the extant ones. Our geometric morphometric analysis of a 15 landmark-based configuration of platyrrhines' first and second lower molars suggest that morphological stasis, may explain the reduced molar shape variation observed. Platyrrhine lower molar shape might be a primitive retention of the ancestral state affected by strong ecological constraints thoughout the radiation the main platyrrhine families. The Patagonian fossil specimens showed two distinct morphological patterns of lower molars, Callicebus -like and Saguinus -like, which might be the precursors of the extant forms, whereas the Middle Miocene specimens, though showing morphological resemblances with the Patagonian fossils, also displayed new, derived molar patternss, Alouatta- like and Pitheciinae -like, thereby suggesting that despite the overall morphological stasis of molars, phenotypic diversification of molar shape was already settled during the Middle Miocene.
Author Comment
Minor editorial corrections have been made. Measurement error has been analyzed and the results have been included.