Rotation of middle ear ossicles during cetacean development.

Title

Rotation of middle ear ossicles during cetacean development.

Creator

Kinkel M D; Thewissen J G; Oelschlager H A

Publisher

Journal of morphology

Date

2001
2001-08

Description

Cetacean middle ears are unique among mammals in that they have an elongated tympanic membrane, a greatly reduced manubrium mallei, and an incudal crus longum that is shorter than the crus breve. Elongation of the tympanic membrane and reduction of the manubrium is thought to be related to an evolutionary rotation of the incus and malleus out of the plane of the tympanic membrane. We examined if rotation also occurs during ontogeny by comparing the middle ears of two species of dolphins (Delphinus delphis, Stenella attenuata) at different stages of development. We observed that: the incus has the body and crural proportions as in terrestrial mammals early in development; the incudomallear complex rotates approximately 90 degrees following ossification; the tympanic membrane is not elongated until relatively late in development. Therefore, some of the unique characteristics of the cetacean middle ear develop as modifications of an initially terrestrial-like morphology.

Subject

*Rotation; Animals; Body Patterning/*physiology; Dolphins/*embryology/*growth & development/physiology; Ear Ossicles/*embryology/*growth & development/physiology; Hearing/*physiology

Identifier

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

126–131

Issue

2

Volume

249

Citation

Kinkel M D; Thewissen J G; Oelschlager H A, “Rotation of middle ear ossicles during cetacean development.,” NEOMED Bibliography Database, accessed June 23, 2024, https://neomed.omeka.net/items/show/3051.