Convergent evolution in toothed whale cochleae

摘要: Odontocetes (toothed whales) are the most species-rich marine mammal lineage. The catalyst for their evolutionary success is echolocation - a form of biological sonar that uses high-frequency sound, produced in forehead and ultimately detected by cochlea. ubiquity odontocetes across wide range physical acoustic environments suggests convergent evolution cochlear shape likely to have occurred. To test this, we used SURFACE; method fits Ornstein-Uhlenbeck (OU) models with stepwise AIC (Akaike Information Criterion) identify regimes on odontocete phylogeny, then tested whether convergence these was significantly greater than expected chance. We identified three regimes: (1) True’s (Mesoplodon mirus) Cuvier’s (Ziphius cavirostris) beaked whales; (2) sperm whales (Physeter macrocephalus) all other sampled; (3) pygmy (Kogia breviceps) dwarf sima) Dall’s porpoise (Phocoenoides dalli). Interestingly ‘river dolphins’, group notorious morphologies riverine ecologies, do not shapes. first two were convergent, habitat type dive correlated membership whale + regime. extreme environment deep ocean constrains shape, causing morphology converge. This study adds support being predict ecology extinct cetaceans.