[MARMAM] Fwd: New article on the ontogeny and evolution of the sound-generating structures in dolphins

Guilherme Frainer gui.frainer at gmail.com
Tue Oct 1 07:28:15 PDT 2019

Dear all,

We are happy to share our recent publication in Biological Journal of the
Linnean Society.

Link: https://doi.org/10.1093/biolinnean/blz118


The ontogeny of the structures involved in sound generation and modulation
in dolphins was investigated through a comparison of the soft nasal
structures of foetal, perinatal, neonatal and adult specimens of
Pontoporiidae, Phocoenidae and Delphinidae. Foetal samples were sectioned
at 10 μm in the saggital and coronal planes, and stained for histological
examination. Computed tomography and magentic resonance imaging scan series
were combined with new data to represent the ontogenetic stages of the
three groups. The images were analysed in 3D-Slicer to characterize the
general head topography. The origins of the melon and the vestibular air
sac were detected between Carnegie stages C16 and F22. The three groups
analysed showed distinct formation of the nasal plug and nasal plug
muscles, mainly with regard to the loss of fat pathways (or their
maintenance in Pontoporiidae) and the development of the nasal plug muscles
on both sides (during perinatal development of Phocoenidae) or just on the
left side (during postnatal development in Delphinidae). Broadband
vocalizing delphinidans might have evolved under heterochronic events
acting on the formation of sound-generating structures such as the rostrum
and vestibular air sacs, and on the transformation of the branches of the
melon, probably leading to a reduced directionality of the sonar beam.

All the best,


*Guilherme Frainer *

Programa de Pós-Graduação em Biologia Animal (PPGBAN/UFRGS). Departamento
De Zoologia. Universidade Federal do Rio Grande do Sul.

de vírus. www.avg.com
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