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The morphogenic features of otoconia during larval development of Cynops pyrrhogaster, the Japanese red-bellied newtOtoconia are calcified protein matrices within the gravity-sensing organs of the vertebrate vestibular system. Mammalian otoconia are barrel-shaped with triplanar facets at each end. Reptilian otoconia are commonly prismatic or fusiform in shape. Amphibians have all three otoconial morphologies, barrel-shaped otoconia within the utricle, with prismatic and fusiform otoconia in the saccule. Scanning electron microscopy revealed a sequential appearance of all three otoconial morphologies during larval development of the newt, Cynops pyrrhogaster. The first otoconia appear within a single, developing otolith, and some resemble adult barrel-shaped otoconia. As the larvae hatch, around stages 39-42, the single otolith divides into two anatomically separate regions, the utricle and saccule, and both contain otoconia similar to those seen in the single otolith. Throughout development, these otoconia may have variable morphologies, with serrated surfaces, or circumferential striations with either separated facets or adjacent facets in the triplanar end-regions. Small fusiform otoconia occur later, at stage 51, and only in the saccule. Prismatic otoconia appear later still, at stage 55, and again only in the saccule. Thus, although prismatic otoconia are the most numerous in adult newts, it is the last vestibular otoconial morphology to be expressed.
Document ID
20050000209
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Steyger, P. S.
(University of Texas Health Science Center at San Antonio 78284-7777 United States)
Wiederhold, M. L.
Batten, J.
Date Acquired
August 22, 2013
Publication Date
April 1, 1995
Publication Information
Publication: Hearing research
Volume: 84
Issue: 1-2
ISSN: 0378-5955
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Neuroscience
Non-NASA Center

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