The spiral ganglion and Rosenthal's canal in beluga whales

Sensor, Jennifer D.; Suydam, Robert; George, J. C.; Liberman, M. Charles; Lovano, Denise M.; Rhaganti, Mary Ann; Usip, Sharon; Vinyard, Christopher J.; Thewissen, J. G. M.

doi:10.1002/jmor.20434

Cited by 11 publications

(14 citation statements)

References 40 publications

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“…The number of turns found in our samples was two, which corresponds to previous work by Sensor et al (2015) in which they found 1.75-2 turns in the ears of beluga whales. Ketten and Wartzok (1990) categorized marine species as specialists with two distinct cochlear morphologies, separated into Type I (high frequency) and Type II (low frequency) (reviewed in Ketten 1992aKetten , 1992b.…”

Section: Discussionsupporting

confidence: 91%

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Description of Cochlear Morphology and Hair Cell Variation in the Beluga Whale

Girdlestone¹,

Piscitelli-Doshkov²,

Ostertag³

et al. 2017

Arctic Science

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Environmental change and decreased ice cover in the Arctic make new areas accessible to humans and animals. It is important to understand how these changes impact marine mammals, such as beluga whales (Delphinapterus leucas Pallas, 1776). Hearing is crucial in the daily lives of cetaceans. Consequently, we need normal baselines to further understand how anthropogenic noise affects these animals. Relatively little is known about the inner ear morphology of belugas, particularly the organ of Corti, or hearing organ, found within the cochlea. The base of the cochlea encodes for high-frequency sounds, while low frequencies are detected in the apex. We showed differences between the apex, or centremost point of the cochlea, and the base, the region closest to the stapes. Our results showed that average outer hair cell density changed from 148 cells/mm in the apex to 117 cells/mm in the base. Cell width varied between the two regions, from 5.8 μm in the apex to 8.4 μm in the base. These results revealed variation throughout the cochlea, and thus the need to understand the basic morphology, to give further insight on hearing function in belugas and allow us to recognize damage if or when we find it.

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Section: Discussionsupporting

confidence: 91%

“…Instead, earlier work describes the density and counts of the spiral ganglion cells or afferent neuron cell body counts (Gao and Zhou 1992;Ketten 2000;Sensor et al 2015). In our study, the total number of hair cells (inner and outer combined) was conservatively calculated to be 9535-28 927 based on absolute minimum and maximum counts.…”

Section: Discussionmentioning

confidence: 99%

Description of Cochlear Morphology and Hair Cell Variation in the Beluga Whale

Girdlestone¹,

Piscitelli-Doshkov²,

Ostertag³

et al. 2017

Arctic Science

View full text Add to dashboard Cite

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“…The smaller and thinner size of the same canal in D. leucas was also visible in a previous study (Sensor et al. ). These differences may be useful phylogenetic differences to note for future morphological phylogenetic studies.…”

Section: Discussionsupporting

confidence: 82%

“…Sensor et al. ; Figs and ). The canaliculus cochleae for the cochlear aqueduct is transversely thinner along its length in all specimens of D. leucas compared with any M. monoceros specimen (e.g.…”

Section: Resultsmentioning

confidence: 95%

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Neuroanatomy and inner ear labyrinths of the narwhal, Monodon monoceros, and beluga, Delphinapterus leucas (Cetacea: Monodontidae)

2018

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Narwhals (Monodon monoceros) and belugas (Delphinapterus leucas) are the only extant members of the Monodontidae, and are charismatic Arctic-endemic cetaceans that are at risk from global change. Investigating the anatomy and sensory apparatuses of these animals is essential to understanding their ecology and evolution, and informs efforts for their conservation. Here, we use X-ray CT scans to compare aspects of the endocranial and inner ear labyrinth anatomy of extant monodontids and use the overall morphology to draw larger inferences about the relationship between morphology and ecology. We show that differences in the shape of the brain, vasculature, and neural canals of both species may relate to differences in diving and other behaviors. The cochleae are similar in morphology in the two species, signifying similar hearing ranges and a close evolutionary relationship. Lastly, we compare two different methods for calculating 90var - a calculation independent of body size that is increasingly being used as a proxy for habitat preference. We show that a 'direct' angular measurement method shows significant differences between Arctic and other habitat preferences, but angle measurements based on planes through the semicircular canals do not, emphasizing the need for more detailed study and standardization of this measurement. This work represents the first comparative internal anatomical study of the endocranium and inner ear labyrinths of this small clade of toothed whales.

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Review and experimental evaluation of the embryonic development and evolutionary history of flipper development and hyperphalangy in dolphins (Cetacea: Mammalia)

Cooper

Sears

Armfield

et al. 2017

Genesis

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SummaryCetaceans are the only mammals to have evolved hyperphalangy, an increase in the number of phalanges beyond the mammalian plesiomorphic condition of three phalanges per digit. In this study, cetaceans were used as a novel model to review previous studies of mammalian hyperphalangy and contribute new experimental evidence as to the molecular origins of this phenotype in embryos of the pantropical spotted dolphin (Stenella attenuata). Results show embryos of dolphins, mice, and pigs share similar spatiotemporal patterns of signaling proteins known to shape limbs of mammals (e.g., and delphinids, and was probably associated with a wave of signaling within the interdigital tissues.

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The spiral ganglion and Rosenthal's canal in beluga whales

Cited by 11 publications

References 40 publications

Description of Cochlear Morphology and Hair Cell Variation in the Beluga Whale

Description of Cochlear Morphology and Hair Cell Variation in the Beluga Whale

Neuroanatomy and inner ear labyrinths of the narwhal, Monodon monoceros, and beluga, Delphinapterus leucas (Cetacea: Monodontidae)

Review and experimental evaluation of the embryonic development and evolutionary history of flipper development and hyperphalangy in dolphins (Cetacea: Mammalia)

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