Lungfish Hearing

Implications for the evolution of the tetrapod middle ear

Christian Bech Christensen, Peter Teglberg Madsen, Jakob Christensen-Dalsgaard

Research output: Contribution to conference without publisher/journalConference abstract for conferenceResearch

Abstract

Recent research has shown that tympanic middle ears
evolved independently in the major vertebrate groups and
represent independent experiments in terrestrial hearing.
Furthermore, the tympanic ear emerged quite late – ap
-
proximately 120 mya after the origin of the tetrapods and
approximately 70 my after the first truly terrestrial tetrapods
emerged. One of the major challenges is to understand the
transitional stages from tetrapod ancestors to the tympanic
tetrapod ear, for example how a non-tympanic ear functions
in terrestrial hearing. Lungfish are the closest living relatives
of the tetrapods, and the ear of lungfish may be similar to the
ear of theearly tetrapods.
We have studied the sensitivity of African lungfish to air-borne
sound, underwater sound and vibrations. We show that lung
-
fish detect underwater sound pressure via pressure-to-par
-
ticle motion transduction by air volumes in their lungs and
that lungfish detect air-borne sound by sound-induced head
vibrations, resulting in a limited sensitivity to low-frequen
-
cy sound (lowest thresholds from 80 dB SPL). Adiditionally,
lungfish are sensitive to substrate vibration with a sensitivity
comparable to anurans and urodeles.
Based on ABR and vibration measurements also on amphib
-
ians, lizards, snakes and alligators we can outline scenarios
for the initial adaptations of the middle ear to non-tympanic
hearing and assess the selection pressures later adapting the
middle ear for tympanic hearing. Hearing by bone conduc
-
tion, sound induced vibrations of the skull, is found in snakes
and some earless frogs, whereas urodeles and other earless
frogs are more sensitive than predicted from sound-induced
skull vibrations and may have specialized pathways to the
inner ear. We propose four stages : 1) the unspecialized cros
-
sopterygian ear with immobile middle ear bone, 2) increased
inner ear frequency ranges, 3) mobile middle ear structures
and 4) the tympanic middle ear.
Original languageEnglish
Publication date21. Feb 2015
Publication statusPublished - 21. Feb 2015
Event38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology - Baltimore Marriott Waterfront, Baltimore, Denmark
Duration: 21. Feb 201525. Feb 2015

Conference

Conference38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology
LocationBaltimore Marriott Waterfront
CountryDenmark
CityBaltimore
Period21/02/201525/02/2015

Cite this

Christensen, C. B., Madsen, P. T., & Christensen-Dalsgaard, J. (2015). Lungfish Hearing: Implications for the evolution of the tetrapod middle ear. Abstract from 38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology, Baltimore, Denmark.
Christensen, Christian Bech ; Madsen, Peter Teglberg ; Christensen-Dalsgaard, Jakob. / Lungfish Hearing : Implications for the evolution of the tetrapod middle ear. Abstract from 38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology, Baltimore, Denmark.
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abstract = "Recent research has shown that tympanic middle earsevolved independently in the major vertebrate groups andrepresent independent experiments in terrestrial hearing.Furthermore, the tympanic ear emerged quite late – ap-proximately 120 mya after the origin of the tetrapods andapproximately 70 my after the first truly terrestrial tetrapodsemerged. One of the major challenges is to understand thetransitional stages from tetrapod ancestors to the tympanictetrapod ear, for example how a non-tympanic ear functionsin terrestrial hearing. Lungfish are the closest living relativesof the tetrapods, and the ear of lungfish may be similar to theear of theearly tetrapods.We have studied the sensitivity of African lungfish to air-bornesound, underwater sound and vibrations. We show that lung-fish detect underwater sound pressure via pressure-to-par-ticle motion transduction by air volumes in their lungs andthat lungfish detect air-borne sound by sound-induced headvibrations, resulting in a limited sensitivity to low-frequen-cy sound (lowest thresholds from 80 dB SPL). Adiditionally,lungfish are sensitive to substrate vibration with a sensitivitycomparable to anurans and urodeles.Based on ABR and vibration measurements also on amphib-ians, lizards, snakes and alligators we can outline scenariosfor the initial adaptations of the middle ear to non-tympanichearing and assess the selection pressures later adapting themiddle ear for tympanic hearing. Hearing by bone conduc-tion, sound induced vibrations of the skull, is found in snakesand some earless frogs, whereas urodeles and other earlessfrogs are more sensitive than predicted from sound-inducedskull vibrations and may have specialized pathways to theinner ear. We propose four stages : 1) the unspecialized cros-sopterygian ear with immobile middle ear bone, 2) increasedinner ear frequency ranges, 3) mobile middle ear structuresand 4) the tympanic middle ear.",
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Christensen, CB, Madsen, PT & Christensen-Dalsgaard, J 2015, 'Lungfish Hearing: Implications for the evolution of the tetrapod middle ear' 38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology, Baltimore, Denmark, 21/02/2015 - 25/02/2015, .

Lungfish Hearing : Implications for the evolution of the tetrapod middle ear. / Christensen, Christian Bech; Madsen, Peter Teglberg; Christensen-Dalsgaard, Jakob.

2015. Abstract from 38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology, Baltimore, Denmark.

Research output: Contribution to conference without publisher/journalConference abstract for conferenceResearch

TY - ABST

T1 - Lungfish Hearing

T2 - Implications for the evolution of the tetrapod middle ear

AU - Christensen, Christian Bech

AU - Madsen, Peter Teglberg

AU - Christensen-Dalsgaard, Jakob

PY - 2015/2/21

Y1 - 2015/2/21

N2 - Recent research has shown that tympanic middle earsevolved independently in the major vertebrate groups andrepresent independent experiments in terrestrial hearing.Furthermore, the tympanic ear emerged quite late – ap-proximately 120 mya after the origin of the tetrapods andapproximately 70 my after the first truly terrestrial tetrapodsemerged. One of the major challenges is to understand thetransitional stages from tetrapod ancestors to the tympanictetrapod ear, for example how a non-tympanic ear functionsin terrestrial hearing. Lungfish are the closest living relativesof the tetrapods, and the ear of lungfish may be similar to theear of theearly tetrapods.We have studied the sensitivity of African lungfish to air-bornesound, underwater sound and vibrations. We show that lung-fish detect underwater sound pressure via pressure-to-par-ticle motion transduction by air volumes in their lungs andthat lungfish detect air-borne sound by sound-induced headvibrations, resulting in a limited sensitivity to low-frequen-cy sound (lowest thresholds from 80 dB SPL). Adiditionally,lungfish are sensitive to substrate vibration with a sensitivitycomparable to anurans and urodeles.Based on ABR and vibration measurements also on amphib-ians, lizards, snakes and alligators we can outline scenariosfor the initial adaptations of the middle ear to non-tympanichearing and assess the selection pressures later adapting themiddle ear for tympanic hearing. Hearing by bone conduc-tion, sound induced vibrations of the skull, is found in snakesand some earless frogs, whereas urodeles and other earlessfrogs are more sensitive than predicted from sound-inducedskull vibrations and may have specialized pathways to theinner ear. We propose four stages : 1) the unspecialized cros-sopterygian ear with immobile middle ear bone, 2) increasedinner ear frequency ranges, 3) mobile middle ear structuresand 4) the tympanic middle ear.

AB - Recent research has shown that tympanic middle earsevolved independently in the major vertebrate groups andrepresent independent experiments in terrestrial hearing.Furthermore, the tympanic ear emerged quite late – ap-proximately 120 mya after the origin of the tetrapods andapproximately 70 my after the first truly terrestrial tetrapodsemerged. One of the major challenges is to understand thetransitional stages from tetrapod ancestors to the tympanictetrapod ear, for example how a non-tympanic ear functionsin terrestrial hearing. Lungfish are the closest living relativesof the tetrapods, and the ear of lungfish may be similar to theear of theearly tetrapods.We have studied the sensitivity of African lungfish to air-bornesound, underwater sound and vibrations. We show that lung-fish detect underwater sound pressure via pressure-to-par-ticle motion transduction by air volumes in their lungs andthat lungfish detect air-borne sound by sound-induced headvibrations, resulting in a limited sensitivity to low-frequen-cy sound (lowest thresholds from 80 dB SPL). Adiditionally,lungfish are sensitive to substrate vibration with a sensitivitycomparable to anurans and urodeles.Based on ABR and vibration measurements also on amphib-ians, lizards, snakes and alligators we can outline scenariosfor the initial adaptations of the middle ear to non-tympanichearing and assess the selection pressures later adapting themiddle ear for tympanic hearing. Hearing by bone conduc-tion, sound induced vibrations of the skull, is found in snakesand some earless frogs, whereas urodeles and other earlessfrogs are more sensitive than predicted from sound-inducedskull vibrations and may have specialized pathways to theinner ear. We propose four stages : 1) the unspecialized cros-sopterygian ear with immobile middle ear bone, 2) increasedinner ear frequency ranges, 3) mobile middle ear structuresand 4) the tympanic middle ear.

KW - mellemøre, evolution, trommehinde

M3 - Conference abstract for conference

ER -

Christensen CB, Madsen PT, Christensen-Dalsgaard J. Lungfish Hearing: Implications for the evolution of the tetrapod middle ear. 2015. Abstract from 38th Annual Midwinter Meeting of the Association for Research in Otorhinolaryngology, Baltimore, Denmark.