Wonky whales: the evolution of cranial asymmetry in cetaceans.

ABSTRACT:

Background

Unlike most mammals, toothed whale (Odontoceti) skulls lack symmetry in the nasal and facial (nasofacial) region. This asymmetry is hypothesised to relate to echolocation, which may have evolved in the earliest diverging odontocetes. Early cetaceans (whales, dolphins, and porpoises) such as archaeocetes, namely the protocetids and basilosaurids, have asymmetric rostra, but it is unclear when nasofacial asymmetry evolved during the transition from archaeocetes to modern whales. We used three-dimensional geometric morphometrics and phylogenetic comparative methods to reconstruct the evolution of asymmetry in the skulls of 162 living and extinct cetaceans over 50 million years.

Results

In archaeocetes, we found asymmetry is prevalent in the rostrum and also in the sq

SUBMITTER: Coombs EJ 

PROVIDER: S-EPMC7350770 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature