Hearing the puzzle: The inner ear evolution of Platanistoidea (Cetacea: Odontoceti)

Abstract

Hearing is one of the key senses for modern cetaceans (Neoceti) to hunting and communication, adapted for either infrasonic (Mysticeti) or ultrasonic (Odontoceti) frequencies. Among odontocetes, the Platanistoidea comprises a single extant riverine representative (Platanista gangetica) but numerous extinct marine species from the late Oligocene onward. Platanista is a critically endangered odontocete species that possess unique morphological characteristics, but their evolutionary patterns remain mostly unknown. Studying extinct platanistoids' hearing abilities might contribute a piece to the complex evolutionary puzzle of this group to understand its drastic diversity reduction. Thus, we describe for the first time the inner ear morphology of 6 late Oligocene–early Miocene extinct marine platanistoids from New Zealand and Patagonia (Argentina).