Great Ears: Low-Frequency Sensitivity Correlates in Land and Marine Leviathans

Ketten, Darlene R.; Arruda, Julie; Cramer, Scott; Yamato, Maya

doi:10.1007/978-1-4939-2981-8_64

Cited by 12 publications

(18 citation statements)

References 14 publications

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“…Number of cochlear turns, deemed functionally insignificant by Fleischer (1976a), was already identified as an indicator for LF hearing sensitivity by West (1985). Interestingly, radii ratio has previously only been linked to LF hearing limits or thresholds in hearing generalists Manoussaki et al, 2008) and LF specialists (Ketten et al, 2016). In this study; however, radii ratio is connected to PC1, number of turns, and HF hearing limit.…”

Section: Interpretation Of the Correlationsmentioning

confidence: 41%

“…The ratio of the most basal and the most apical cochlear turns was determined according to the method as introduced by Manoussaki et al (2008), allowing both turns to have one centrum each, as opposed to a common centrum on the modiolar axis (cf. Chadwick et al, 2006;Ekdale and Racicot, 2015;Ketten et al, 2016). For the determination of the radii of curvature of these turns the line representative of the basilar membrane (derived as described above) was projected in apical view onto an isometric twodimensional (2-D) grid created with MatheKonstruktor (http: //www.martware.de/mathekonstruktor.html, last accessed 14 April 2016).…”

Section: Number Of Turns and Radii Ratiomentioning

confidence: 99%

“…A different procedure to determine basal and apical radii was used by Chadwick et al (2006), Ekdale and Racicot (2015), and Ketten et al (2016). These authors connected one point at the basal end and one point at the apical end of the basilar membrane each to a common center, positioned either at the center of the spiral or at the center of the modiolus, in an orthogonal 2-D projection of the cochlea.…”

Section: S Ritsche Et Al: Relationships Of Cochlear Coiling Shapmentioning

confidence: 99%

“…Various methods have been applied to test such a relationship, using either individual variables, and products thereof, such as number of turns and basilar membrane length (West, 1985), the ratio of the radii of the basal and apical turns (Manoussaki et al, 2008), or cochlear shape (Wannaprasert and Jeffery, 2015). However, these methods have either been used in incomparable ways, e.g., radii ratio measured from the modiolar axis Ekdale and Racicot, 2015;Ketten et al, 2016) or using individual spiral centers for each measurement of basal and apical turn (Manoussaki et al, 2008), or they have been applied to a variety of mammals, mainly including hearing generalists (Manoussaki et al, 2008;Wannaprasert and Jeffery, 2015), not shedding much light on hearing in cetaceans in particular. Also, Ketten (1992) and Ketten et al (2016) used basilar membrane width and thickness as correlates for LF sensitivity in whales.…”

Section: Introductionmentioning

confidence: 99%

“…However, these methods have either been used in incomparable ways, e.g., radii ratio measured from the modiolar axis Ekdale and Racicot, 2015;Ketten et al, 2016) or using individual spiral centers for each measurement of basal and apical turn (Manoussaki et al, 2008), or they have been applied to a variety of mammals, mainly including hearing generalists (Manoussaki et al, 2008;Wannaprasert and Jeffery, 2015), not shedding much light on hearing in cetaceans in particular. Also, Ketten (1992) and Ketten et al (2016) used basilar membrane width and thickness as correlates for LF sensitivity in whales. However, soft tissue is not preserved in fossil cochleae, and osteological features that indicate the extent of the basilar membrane, such as the secondary bony lamina, are very delicate and do not preserve well (Ekdale and Racicot, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti

et al. 2018

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Abstract. Baleen whales (Mysticeti) are known to use low frequencies (LF; 200 Hz and below) and infrasound (< 20 Hz) for communication. The lowest hearing limits of toothed whales (Odontoceti), which are able to produce ultrasound (> 20 kHz), reach low frequencies. Researchers have tried to understand the evolution of LF and infrasonic hearing in mysticetes by linking the shape of the inner ear cochlea or individual cochlear measurements to known hearing frequencies and making inferences to extinct species. Using landmark-based shape analysis of complete cochlear coiling, we show that cochlear coiling shape correlates with LF and high-frequency (HF; > 10 kHz) hearing limits in cetaceans. Very LF ( ≤ 50 Hz) and infrasonic hearing are associated with, for example, a protruding second turn, a descending apex, and a high number of turns. Correlations between cochlear and cranial variables and cochlear and cranial shape indicate that low LF hearing limits are furthermore connected to longer cochleae and relatively larger cranial widths. Very LF hearing in Mysticeti appeared in the middle Miocene, and mysticete infrasonic hearing had evolved by the late Miocene. Complete cochlear coiling is suitable for estimating hearing limits in cetaceans, closely approximated by cochlear length times number of cochlear turns.

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Section: Interpretation Of the Correlationsmentioning

confidence: 41%

Section: Number Of Turns and Radii Ratiomentioning

confidence: 99%

Section: S Ritsche Et Al: Relationships Of Cochlear Coiling Shapmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti

et al. 2018

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Evolution of whale sensory ecology: Frontiers in nondestructive anatomical investigations

Racicot

2021

The Anatomical Record

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Studies surrounding the evolution of sensory system anatomy in cetaceans over the last ~100 years have shed light on aspects of the early evolution of hearing sensitivities, the small relative size of the organ of balance (semicircular canals and vestibule), brain (endocast) shape and relative volume changes, and ontogenetic development of sensory-related structures. Here, I review advances in our knowledge of sensory system anatomy as informed by the use of nondestructive imaging techniques, with a focus on applied methods in computed tomography (CT and μCT), and identify the key questions that remain to be addressed. Of these, the most important are: Is lower frequency hearing sensitivity the ancestral condition for whales? Did echolocation evolve more than once in odontocetes; and if so, when and why? How has the structure of the cetacean brain changed, through the evolution of whales, and does this correspond to changes in hearing sensitivities? Finally, what are the general pathways of ontogenetic development of sensory systems in odontocetes and mysticetes? Answering these questions will allow us to understand important macroevolutionary patterns in a fully aquatic mammalian group and provides baseline data on species for which we have limited biological information because of logistical limitations.

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Morphological variation among the inner ears of extinct and extant baleen whales (Cetacea: Mysticeti)

Ekdale

2016

Journal of Morphology

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Living mysticetes (baleen whales) and odontocetes (toothed whales) differ significantly in auditory function in that toothed whales are sensitive to high-frequency and ultrasonic sound vibrations and mysticetes to low-frequency and infrasonic noises. Our knowledge of the evolution and phylogeny of cetaceans, and mysticetes in particular, is at a point at which we can explore morphological and physiological changes within the baleen whale inner ear. Traditional comparative anatomy and landmark-based 3D-geometric morphometric analyses were performed to investigate the anatomical diversity of the inner ears of extinct and extant mysticetes in comparison with other cetaceans. Principal component analyses (PCAs) show that the cochlear morphospace of odontocetes is tangential to that of mysticetes, but odontocetes are completely separated from mysticetes when semicircular canal landmarks are combined with the cochlear data. The cochlea of the archaeocete Zygorhiza kochii and early diverging extinct mysticetes plot within the morphospace of crown mysticetes, suggesting that mysticetes possess ancestral cochlear morphology and physiology. The PCA results indicate variation among mysticete species, although no major patterns are recovered to suggest separate hearing or locomotor regimes. Phylogenetic signal was detected for several clades, including crown Cetacea and crown Mysticeti, with the most clades expressing phylogenetic signal in the semicircular canal dataset. Brownian motion could not be excluded as an explanation for the signal, except for analyses combining cochlea and semicircular canal datasets for Balaenopteridae. J. Morphol. 277:1599-1615, 2016. © 2016 Wiley Periodicals, Inc.

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Great Ears: Low-Frequency Sensitivity Correlates in Land and Marine Leviathans

Cited by 12 publications

References 14 publications

Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti

Relationships of cochlear coiling shape and hearing frequencies in cetaceans, and the occurrence of infrasonic hearing in Miocene Mysticeti

Evolution of whale sensory ecology: Frontiers in nondestructive anatomical investigations

Morphological variation among the inner ears of extinct and extant baleen whales (Cetacea: Mysticeti)

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