Disparate heterochronic processes in baleen whale evolution
Journal
Evolutionary Biology
Journal Volume
41
Journal Issue
2
Start Page
299
End Page
307
ISSN
0071-3260
Date Issued
2014-01-17
Author(s)
R. Ewan Fordyce
Abstract
Skulls of living baleen whales show distinctive patterns of heterochronic ontogenetic change with implications for mysticete evolution. Here, three baleen whale species are analysed and considered in a heterochronic context. Landmarks show that, during ontogeny, skull morphology changes significantly in the rorqual Balaenoptera borealis and humpback Megaptera novaeangliae (both Balaenopteridae), while the pygmy right whale Caperea marginata (Cetotheriidae: Neobalaeninae) retains an overall juvenile morphology from foetus to adult. Geometric morphometric analyses show that foetal and adult C. marginata are similar, whereas the balaenopterids are more disparate: foetal M. novaeangliae and B. borealis appear in one group, and adult M. novaeangliae and B. borealis are grouped closely. Heterochrony involves paedomorphosis for Caperea, and peramorphosis for the balaenopterids. Heterochrony might cause limited or released developmental constraints, leading to low taxonomic diversity in the single surviving species of neobalaenine, and higher diversity amongst balaenopterids. © 2014 Springer Science+Business Media New York.
Subjects
Evolution
Heterochrony
Morphology
Mysticete
Ontogeny
SDGs
Publisher
Springer Verlag
Type
journal article