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Zhao L, Zhang M, Qin Y, Wang T, Zhai X, Cui J, Wang J. Auditory sensitivity and tympanic middle ear in a vocal and a non-vocal frog. Hear Res 2024; 444:108970. [PMID: 38367458 DOI: 10.1016/j.heares.2024.108970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/01/2024] [Accepted: 02/04/2024] [Indexed: 02/19/2024]
Abstract
The tympanic middle ear is important for anuran hearing on land. However, many species have partly or entirely lost their tympanic apparatus. Previous studies have compared hearing sensitivities in species that possess and lack tympanic membranes capable of sound production and acoustic communication. However, little is known about how these hearing abilities are comparable to those of mutant species. Here, we compared the eardrum and middle ear anatomies of two sympatric sibling species from a noisy stream habitat, namely the "non-vocal" Hainan torrent frog (Amolops hainanensis) and the "vocal" little torrent frog (Amolops torrentis), the latter of which is capable of acoustic communication. Our results showed that the relative (to head size) eardrum diameter of A. hainanensis was smaller than that of A. torrentis, although the absolute size was not smaller. Unlike A. torrentis, the tympanic membrane area of A. hainanensis was not clearly differentiated from the surrounding skin. The middle ear, however, was well-developed in both species. We measured the auditory brainstem responses (ABRs) of A. hainanensis and compared the ABR thresholds and latencies to those previously obtained for A. torrentis. Our results suggested that these two species exhibited significant differences in hearing sensitivity. A. hainanensis (smaller relative eardrum, nonvocal) had higher ABR thresholds and longer initial response times than A. torrentis (larger relative eardrum, vocal) at lower frequencies. Neurophysiological responses from the brain were obtained for tone pips between 800 Hz and 7,000 Hz, with peak sensitivities found at 3,000 Hz (73 dB SPL) for A. hainanensis, and at 1,800 Hz (61 dB SPL) for A. torrentis. Our results suggest that the non-vocal A. hainanensis has lower hearing sensitivity than its vocal sister species (i.e., A. torrentis), which may be related to differences in tympanic or inner ear structure and morphology.
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Affiliation(s)
- Longhui Zhao
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China
| | - Meihua Zhang
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China
| | - Yuanyu Qin
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China
| | - Tongliang Wang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China
| | - Xiaofei Zhai
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China
| | - Jianguo Cui
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China.
| | - Jichao Wang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China.
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Womack MC, Hoke KL. Convergent Anuran Middle Ear Loss Lacks a Universal, Adaptive Explanation. BRAIN, BEHAVIOR AND EVOLUTION 2023; 98:290-301. [PMID: 37913755 PMCID: PMC10885836 DOI: 10.1159/000534936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
INTRODUCTION Shared selection pressures often explain convergent trait loss, yet anurans (frogs and toads) have lost their middle ears at least 38 times with no obvious shared selection pressures unifying "earless" taxa. Anuran tympanic middle ear loss is especially perplexing because acoustic communication is dominant within Anura and tympanic middle ears enhance airborne hearing in most tetrapods. METHODS Here, we use phylogenetic comparative methods to examine whether particular geographic ranges, microhabitats, activity patterns, or aspects of acoustic communication are associated with anuran tympanic middle ear loss. RESULTS Although we find some differences between the geographic ranges of eared and earless species on average, there is plenty of overlap between the geographic distributions of eared and earless species. Additionally, we find a higher prevalence of diurnality in earless species, but not all earless species are diurnal. We find no universal adaptive explanation for the many instances of anuran tympanic middle ear loss. CONCLUSION The puzzling lack of universally shared selection pressures among earless species motivates discussion of alternative hypotheses, including genetic or developmental constraints, and the possibility that tympanic middle ear loss is maladaptive.
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Affiliation(s)
| | - Kim L. Hoke
- Biology Department, Colorado State University, Fort Collins, CO, USA
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3
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Capshaw G, Brown AD, Peña JL, Carr CE, Christensen-Dalsgaard J, Tollin DJ, Womack MC, McCullagh EA. The continued importance of comparative auditory research to modern scientific discovery. Hear Res 2023; 433:108766. [PMID: 37084504 DOI: 10.1016/j.heares.2023.108766] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/23/2023] [Accepted: 04/05/2023] [Indexed: 04/23/2023]
Abstract
A rich history of comparative research in the auditory field has afforded a synthetic view of sound information processing by ears and brains. Some organisms have proven to be powerful models for human hearing due to fundamental similarities (e.g., well-matched hearing ranges), while others feature intriguing differences (e.g., atympanic ears) that invite further study. Work across diverse "non-traditional" organisms, from small mammals to avians to amphibians and beyond, continues to propel auditory science forward, netting a variety of biomedical and technological advances along the way. In this brief review, limited primarily to tetrapod vertebrates, we discuss the continued importance of comparative studies in hearing research from the periphery to central nervous system with a focus on outstanding questions such as mechanisms for sound capture, peripheral and central processing of directional/spatial information, and non-canonical auditory processing, including efferent and hormonal effects.
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Affiliation(s)
- Grace Capshaw
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - Andrew D Brown
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA 98105, USA
| | - José L Peña
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Catherine E Carr
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Daniel J Tollin
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Molly C Womack
- Department of Biology, Utah State University, Logan, UT 84322, USA.
| | - Elizabeth A McCullagh
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078, USA.
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Abstract
The ability to sense and localize sound is so advantageous for survival that it is difficult to understand the almost 100 million year gap separating the appearance of early tetrapods and the emergence of an impedance-matching tympanic middle ear - which we normally regard as a prerequisite for sensitive hearing on land - in their descendants. Recent studies of hearing in extant atympanate vertebrates have provided significant insights into the ancestral state(s) and the early evolution of the terrestrial tetrapod auditory system. These reveal a mechanism for sound pressure detection and directional hearing in 'earless' atympanate vertebrates that may be generalizable to all tetrapods, including the earliest terrestrial species. Here, we review the structure and function of vertebrate tympanic middle ears and highlight the multiple acquisition and loss events that characterize the complex evolutionary history of this important sensory structure. We describe extratympanic pathways for sound transmission to the inner ear and synthesize findings from recent studies to propose a general mechanism for hearing in 'earless' atympanate vertebrates. Finally, we integrate these studies with research on tympanate species that may also rely on extratympanic mechanisms for acoustic reception of infrasound (<20 Hz) and with studies on human bone conduction mechanisms of hearing.
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Affiliation(s)
- Grace Capshaw
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Catherine E Carr
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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5
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Zheng Y, Xie F. Underwater calling behavior in two high‐altitude frog species. J Zool (1987) 2022. [DOI: 10.1111/jzo.12960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Y. Zheng
- Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China
| | - F. Xie
- Chengdu Institute of Biology Chinese Academy of Sciences Chengdu China
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6
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Bardua C, Fabre AC, Clavel J, Bon M, Das K, Stanley EL, Blackburn DC, Goswami A. Size, microhabitat, and loss of larval feeding drive cranial diversification in frogs. Nat Commun 2021; 12:2503. [PMID: 33947859 PMCID: PMC8096824 DOI: 10.1038/s41467-021-22792-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 03/25/2021] [Indexed: 02/02/2023] Open
Abstract
Habitat is one of the most important factors shaping organismal morphology, but it may vary across life history stages. Ontogenetic shifts in ecology may introduce antagonistic selection that constrains adult phenotype, particularly with ecologically distinct developmental phases such as the free-living, feeding larval stage of many frogs (Lissamphibia: Anura). We test the relative influences of developmental and ecological factors on the diversification of adult skull morphology with a detailed analysis of 15 individual cranial regions across 173 anuran species, representing every extant family. Skull size, adult microhabitat, larval feeding, and ossification timing are all significant factors shaping aspects of cranial evolution in frogs, with late-ossifying elements showing the greatest disparity and fastest evolutionary rates. Size and microhabitat show the strongest effects on cranial shape, and we identify a "large size-wide skull" pattern of anuran, and possibly amphibian, evolutionary allometry. Fossorial and aquatic microhabitats occupy distinct regions of morphospace and display fast evolution and high disparity. Taxa with and without feeding larvae do not notably differ in cranial morphology. However, loss of an actively feeding larval stage is associated with higher evolutionary rates and disparity, suggesting that functional pressures experienced earlier in ontogeny significantly impact adult morphological evolution.
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Affiliation(s)
- Carla Bardua
- Department of Life Sciences, Natural History Museum, London, UK
- Department of Genetics, Evolution & Environment, University College London, London, UK
| | - Anne-Claire Fabre
- Department of Life Sciences, Natural History Museum, London, UK
- Paläontologisches Institut und Museum, Universität Zürich, Zürich, Switzerland
| | - Julien Clavel
- Department of Life Sciences, Natural History Museum, London, UK
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
| | - Margot Bon
- Department of Life Sciences, Natural History Museum, London, UK
| | - Kalpana Das
- Museum für Naturkunde, Leibniz Institut für Evolutions und Biodiversitätsforschung, Berlin, Germany
| | - Edward L Stanley
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - David C Blackburn
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Anjali Goswami
- Department of Life Sciences, Natural History Museum, London, UK.
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7
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Santos MTT, Barata IM, Ferreira RB, Haddad CFB, Gridi-Papp M, de Carvalho TR. Complex acoustic signals in Crossodactylodes (Leptodactylidae, Paratelmatobiinae): a frog genus historically regarded as voiceless. BIOACOUSTICS 2021. [DOI: 10.1080/09524622.2021.1904443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Marcus Thadeu T. Santos
- Laboratório de Herpetologia, Departamento de Zoologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | | | | | - Célio F. B. Haddad
- Laboratório de Herpetologia, Departamento de Biodiversidade e Centro de Aquicultura (CAUNESP), Universidade Estadual Paulista, Rio Claro, Brazil
| | - Marcos Gridi-Papp
- Department of Biological Sciences, University of the Pacific, Stockton, CA, USA
| | - Thiago R. de Carvalho
- Laboratório de Herpetologia, Departamento de Biodiversidade e Centro de Aquicultura (CAUNESP), Universidade Estadual Paulista, Rio Claro, Brazil
- Department of Biological Sciences, University of the Pacific, Stockton, CA, USA
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8
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Christensen-Dalsgaard J, Kuokkanen P, Matthews JE, Carr CE. Strongly directional responses to tones and conspecific calls in the auditory nerve of the Tokay gecko, Gekko gecko. J Neurophysiol 2021; 125:887-902. [PMID: 33534648 DOI: 10.1152/jn.00576.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The configuration of lizard ears, where sound can reach both surfaces of the eardrums, produces a strongly directional ear, but the subsequent processing of sound direction by the auditory pathway is unknown. We report here on directional responses from the first stage, the auditory nerve. We used laser vibrometry to measure eardrum responses in Tokay geckos and in the same animals recorded 117 auditory nerve single fiber responses to free-field sound from radially distributed speakers. Responses from all fibers showed strongly lateralized activity at all frequencies, with an ovoidal directivity that resembled the eardrum directivity. Geckos are vocal and showed pronounced nerve fiber directionality to components of the call. To estimate the accuracy with which a gecko could discriminate between sound sources, we computed the Fisher information (FI) for each neuron. FI was highest just contralateral to the midline, front and back. Thus, the auditory nerve could provide a population code for sound source direction, and geckos should have a high capacity to differentiate between midline sound sources. In brain, binaural comparisons, for example, by IE (ipsilateral excitatory, contralateral inhibitory) neurons, should sharpen the lateralized responses and extend the dynamic range of directionality.NEW & NOTEWORTHY In mammals, the two ears are unconnected pressure receivers, and sound direction is computed from binaural interactions in the brain, but in lizards, the eardrums interact acoustically, producing a strongly directional response. We show strongly lateralized responses from gecko auditory nerve fibers to directional sound stimulation and high Fisher information on either side of the midline. Thus, already the auditory nerve provides a population code for sound source direction in the gecko.
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Affiliation(s)
| | - Paula Kuokkanen
- Department of Biology, Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Catherine E Carr
- Department of Biology, University of Maryland, College Park, Maryland
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9
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Lauridsen TB, Brandt C, Christensen-Dalsgaard J. Three auditory brainstem response (ABR) methods tested and compared in two anuran species. J Exp Biol 2021; 224:jeb237313. [PMID: 33268532 DOI: 10.1242/jeb.237313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/24/2020] [Indexed: 11/20/2022]
Abstract
Hearing sensitivity has been extensively investigated, often by measuring the auditory brainstem response (ABR). ABR measurements are relatively non-invasive, easy to reproduce, and allow the assessment of sensitivity when psychophysical data are difficult to obtain. However, the experimental methods differ greatly in respect to stimulation, which may result in different audiograms. We used three different methods in the same individual frogs: stimulating with brief tone bursts (tABR), long-duration tones (ltABR) and masked ABR (mABR), where transients are masked by a long-duration sinusoid, and the sensitivity is assessed by the difference between unmasked and masked ABR. We measured sensitivity in a range from 100 to 3500 Hz, and the resulting audiograms show two sensitivity peaks at 400-600 Hz and 1500-1600 Hz (both sensitive down to 30 dB re. 20 µPa). We found similar results below 1000 Hz, but when stimulating with long-duration tones, the sensitivity decreased more rapidly above this frequency. We showed that the frequency specificity of tone bursts becomes poorly defined with shorter duration at low frequencies. Comparisons between subjectively (visual inspection by researchers) and objectively (thresholds defined by signal-to-noise ratio) defined audiograms showed very little variation. In conclusion, the mABR method gave the most sensitive audiograms. The tABR method showed a similar audiogram when using relatively long-duration tone bursts (25 ms). The ltABR method is not a good choice for studying hearing thresholds above 1000 Hz because of the bias introduced by spike rate saturation in the nerve fibers and their inability to phase lock.
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Affiliation(s)
- Tanya B Lauridsen
- Department of Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Christian Brandt
- Department of Clinical Research, University of Southern Denmark, 5230 Odense, Denmark
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10
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Capshaw G, Soares D, Christensen-Dalsgaard J, Carr CE. Seismic sensitivity and bone conduction mechanisms enable extratympanic hearing in salamanders. J Exp Biol 2020; 223:jeb236489. [PMID: 33161383 PMCID: PMC7774885 DOI: 10.1242/jeb.236489] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/01/2020] [Indexed: 11/20/2022]
Abstract
The tympanic middle ear is an adaptive sensory novelty that evolved multiple times in all the major terrestrial tetrapod groups to overcome the impedance mismatch generated when aerial sound encounters the air-skin boundary. Many extant tetrapod species have lost their tympanic middle ears, yet they retain the ability to detect airborne sound. In the absence of a functional tympanic ear, extratympanic hearing may occur via the resonant qualities of air-filled body cavities, sensitivity to seismic vibration, and/or bone conduction pathways to transmit sound from the environment to the ear. We used auditory brainstem response recording and laser vibrometry to assess the contributions of these extratympanic pathways for airborne sound in atympanic salamanders. We measured auditory sensitivity thresholds in eight species and observed sensitivity to low-frequency sound and vibration from 0.05-1.2 kHz and 0.02-1.2 kHz, respectively. We determined that sensitivity to airborne sound is not facilitated by the vibrational responsiveness of the lungs or mouth cavity. We further observed that, although seismic sensitivity probably contributes to sound detection under naturalistic scenarios, airborne sound stimuli presented under experimental conditions did not produce vibrations detectable to the salamander ear. Instead, threshold-level sound pressure is sufficient to generate translational movements in the salamander head, and these sound-induced head vibrations are detectable by the acoustic sensors of the inner ear. This extratympanic hearing mechanism mediates low-frequency sensitivity in vertebrate ears that are unspecialized for the detection of aerial sound pressure, and may represent a common mechanism for terrestrial hearing across atympanic tetrapods.
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Affiliation(s)
- G Capshaw
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - D Soares
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA
| | - J Christensen-Dalsgaard
- Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - C E Carr
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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11
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Stynoski JL, Womack MC, Trama FA, Coloma LA, Hoke KL. Whispers from vestigial nubbins: Arrested development provokes trait loss in toads. Evol Dev 2020; 23:5-18. [PMID: 33107688 DOI: 10.1111/ede.12356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/29/2022]
Abstract
Despite the use of acoustic communication, many species of toads (family Bufonidae) have lost parts of the tympanic middle ear, representing at least 12 independent evolutionary occurrences of trait loss. The comparative development of the tympanic middle ear in toads is poorly understood. Here, we compared middle ear development among two pairs of closely related toad species in the genera Atelopus and Rhinella that have (eared) or lack (earless) middle ear structures. We bred toads in Peru and Ecuador, preserved developmental series from tadpoles to juveniles, and examined ontogenetic timing and volume of the otic capsule, oval window, operculum, opercularis muscle, columella (stapes), and extracolumella in three-dimensional histological reconstructions. All species had similar ontogenesis of the otic capsule, oval window, operculum, and opercularis muscle. Moreover, cell clusters of primordial columella in the oval window appeared just before metamorphosis in both eared and earless lineages. However, in earless lineages, the cell clusters either remained as small nubbins or cell buds in the location of the columella footplate within the oval window or disappeared by juvenile and adult stages. Thus, columella growth began around metamorphosis in all species but was truncated and/or degenerated after metamorphosis in earless species, leaving earless adults with morphology typical of metamorphic anurans. Shifts in the timing or expression of biochemical pathways that regulate the extension or differentiation of the columella after metamorphosis may be the developmental mechanism underlying convergent trait loss among toad lineages.
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Affiliation(s)
- Jennifer L Stynoski
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA.,Instituto Clodomiro Picado, Universidad de Costa Rica, Coronado, Costa Rica
| | - Molly C Womack
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Florencia A Trama
- Grupo de Investigación en Entomología y Medio Ambiente, Universidad San Ignacio de Loyola, Lima, Peru.,Centro de Capacitación en Conservación y Desarrollo Sostenible (CDS/CNEH-Perú), Oxapampa, Peru
| | - Luis A Coloma
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Jambatu, Quito, Ecuador
| | - Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
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12
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Stynoski JL, Trama FA, Rizo Patrón FL, Tapia E, Hoke KL. Reproductive Ecology of the Peruvian Earless Toad Rhinella yunga (Amphibia, Bufonidae) with Descriptions of Calls, Tadpole, and Female Competition. SOUTH AMERICAN JOURNAL OF HERPETOLOGY 2020. [DOI: 10.2994/sajh-d-18-00030.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
| | - Florencia A. Trama
- Centro de Capacitación en Conservación y Desarrollo Sostenible, Oxapampa, Peru
| | | | - Elicio Tapia
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Otonga, Quito, Ecuador
| | - Kim L. Hoke
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
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13
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Womack MC, Metz MJ, Hoke KL. Larger Genomes Linked to Slower Development and Loss of Late-Developing Traits. Am Nat 2019; 194:854-864. [PMID: 31738099 DOI: 10.1086/705897] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Genome size varies widely among organisms and is known to affect vertebrate development, morphology, and physiology. In amphibians, genome size is hypothesized to contribute to loss of late-forming structures, although this hypothesis has mainly been discussed in salamanders. Here we estimated genome size for 22 anuran species and combined this novel data set with existing genome size data for an additional 234 anuran species to determine whether larger genome size is associated with loss of a late-forming anuran sensory structure, the tympanic middle ear. We established that genome size is negatively correlated with development rate across 90 anuran species and found that genome size evolution is correlated with evolutionary loss of the middle ear bone (columella) among 241 species (224 eared and 17 earless). We further tested whether the development of the tympanic middle ear could be constrained by large cell sizes and small body sizes during key stages of tympanic middle ear development (metamorphosis). Together, our evidence suggests that larger genomes, slower development rate, and smaller body sizes at metamorphosis may contribute to the loss of the anuran tympanic middle ear. We conclude that increases in anuran genome size, although less drastic than those in salamanders, may affect development of late-forming traits.
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14
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Beatini JR, Proudfoot GA, Gall MD. Effects of presentation rate and onset time on auditory brainstem responses in Northern saw-whet owls (Aegolius acadicus). THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:2062. [PMID: 31046339 DOI: 10.1121/1.5096532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
Monitoring auditory brainstem responses (ABRs) is a common method of assessing auditory processing in non-model species. Although ABRs are widely used to compare auditory abilities across taxa, the extent to which different features of acoustic stimuli affect the ABR is largely unknown in most non-mammalian species. The authors investigated the effects of varying presentation rate and onset time to determine how different features of acoustic stimuli influence the ABR in Northern saw-whet owls (Aegolius acadicus), a species known for their unique auditory adaptations and hunting abilities. At presentation rates ranging from 21.1 to 51.1 s-1, there were no differences in the size or synchrony of ABRs, suggesting that stimuli can be presented at a relatively rapid rate to maximize the number of observations recorded for analysis. While increasing onset time was associated with a decrement in response size and synchrony, tonebursts with 1 ms onset times produced overgeneralized neural responses as a result of spectral splatter. This suggests that 2 to 3 ms onset times may balance the trade-off between response synchrony and frequency specificity when comparing relative neural recruitment across frequencies. These findings highlight the importance of considering stimulus parameters when interpreting ABR data.
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Affiliation(s)
- Julia R Beatini
- Biology Department, Vassar College, Poughkeepsie, New York 12604, USA
| | - Glenn A Proudfoot
- Biology Department, Vassar College, Poughkeepsie, New York 12604, USA
| | - Megan D Gall
- Biology Department, Vassar College, Poughkeepsie, New York 12604, USA
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15
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Ceríaco LMP, Marques MP, Bandeira S, Agarwal I, Stanley EL, Bauer AM, Heinicke MP, Blackburn DC. A new earless species of Poyntonophrynus (Anura, Bufonidae) from the Serra da Neve Inselberg, Namibe Province, Angola. Zookeys 2018:109-136. [PMID: 30127660 PMCID: PMC6093966 DOI: 10.3897/zookeys.780.25859] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/05/2018] [Indexed: 11/16/2022] Open
Abstract
African pygmy toads of the genus Poyntonophrynus are some of the least known species of African toads. The genus comprises ten recognized species endemic to sub-Saharan Africa, five of which are restricted to southwestern Africa. Recent field research in Angola provided new material for three species of Poyntonophrynus, including a morphologically distinctive population from the Serra da Neve Inselberg. Based on a combination of external morphology, high-resolution computed tomography scanning, and molecular phylogenetic analysis, the Serra da Neve population is described as new species that is nested within the genus. The most striking character that differentiates the newly described species from its congeners is the lack of a tympanic middle ear, a condition common in the family Bufonidae, but so far not known for Poyntonophrynus. The description of this new species from southwestern Angola reinforces the biogeographic importance of the region and further suggests that southwestern Africa is the cradle of diversity for this genus.
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Affiliation(s)
- Luis M P Ceríaco
- Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, Michigan 48128, USA University of Michigan-Dearborn Dearborn United States of America.,Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085-1699, USA Universidade de Lisboa Lisbon Portugal.,Museu Nacional de História Natural e da Ciência, Universidade de Lisboa, Rua da Escola Politécnica, 58, 1269-102 Lisboa, Portugal Villanova University Villanova United States of America
| | - Mariana P Marques
- Museu Nacional de História Natural e da Ciência, Universidade de Lisboa, Rua da Escola Politécnica, 58, 1269-102 Lisboa, Portugal Villanova University Villanova United States of America.,Research Center in Biodiversity and Genetic Resources (CIBIO), InBIO, University of Porto, Rua Padre Armando Quintas 7, Vairão, 4485-661 Porto, Portugal University of Porto Porto Portugal
| | - Suzana Bandeira
- Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085-1699, USA Universidade de Lisboa Lisbon Portugal.,Instituto Nacional da Biodiversidade e Áreas de Conservação (INBAC), Ministério do Ambiente de Angola, Centralidade do Kilamba, Rua 26 de Fevereiro, Quarteirão Nimi Ya Lukemi, edifício Q11, 3° andar, Angola Ministério do Ambiente de Angola Luanda Angola
| | - Ishan Agarwal
- Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085-1699, USA Universidade de Lisboa Lisbon Portugal
| | - Edward L Stanley
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA University of Florida Gainsville United States of America
| | - Aaron M Bauer
- Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085-1699, USA Universidade de Lisboa Lisbon Portugal
| | - Matthew P Heinicke
- Department of Natural Sciences, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, Michigan 48128, USA University of Michigan-Dearborn Dearborn United States of America
| | - David C Blackburn
- Department of Natural History, Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA University of Florida Gainsville United States of America
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16
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Womack MC, Christensen-Dalsgaard J, Coloma LA, Hoke KL. Sensitive high-frequency hearing in earless and partially eared harlequin frogs ( Atelopus). ACTA ACUST UNITED AC 2018; 221:jeb.169664. [PMID: 29674377 DOI: 10.1242/jeb.169664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 04/11/2018] [Indexed: 11/20/2022]
Abstract
Harlequin frogs, genus Atelopus, communicate at high frequencies despite most species lacking a complete tympanic middle ear that facilitates high-frequency hearing in most anurans and other tetrapods. Here, we tested whether Atelopus are better at sensing high-frequency acoustic sound compared with other eared and earless species in the Bufonidae family, determined whether middle ear variation within Atelopus affects hearing sensitivity and tested potential hearing mechanisms in Atelopus We determined that at high frequencies (2000-4000 Hz), Atelopus are 10-34 dB more sensitive than other earless bufonids but are relatively insensitive to mid-range frequencies (900-1500 Hz) compared with eared bufonids. Hearing among Atelopus species is fairly consistent, evidence that the partial middle ears present in a subset of Atelopus species do not convey a substantial hearing advantage. We further demonstrate that Atelopus hearing is probably not facilitated by vibration of the skin overlying the normal tympanic membrane region or the body lung wall, leaving the extratympanic hearing pathways in Atelopus enigmatic. Together, these results show Atelopus have sensitive high-frequency hearing without the aid of a tympanic middle ear and prompt further study of extratympanic hearing mechanisms in anurans.
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Affiliation(s)
- Molly C Womack
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | | | - Luis A Coloma
- Centro Jambatu de Investigación y Conservación de Anfibios, Fundación Otonga, Giovanni Farina 566 y Baltra, San Rafael, Quito, Ecuador
| | - Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
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17
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von May R, Lehr E, Rabosky DL. Evolutionary radiation of earless frogs in the Andes: molecular phylogenetics and habitat shifts in high-elevation terrestrial breeding frogs. PeerJ 2018; 6:e4313. [PMID: 29492332 PMCID: PMC5825883 DOI: 10.7717/peerj.4313] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 01/11/2018] [Indexed: 11/20/2022] Open
Abstract
The loss of hearing structures and loss of advertisement calls in many terrestrial breeding frogs (Strabomantidae) living at high elevations in South America are common and intriguing phenomena. The Andean frog genus Phrynopus Peters, 1873 has undergone an evolutionary radiation in which most species lack the tympanic membrane and tympanic annulus, yet the phylogenetic relationships among species in this group remain largely unknown. Here, we present an expanded molecular phylogeny of Phrynopus that includes 24 nominal species. Our phylogeny includes Phrynopus peruanus, the type species of the genus, and 10 other species for which genetic data were previously unavailable. We found strong support for monophyly of Phrynopus, and that two nominal species-Phrynopus curator and Phrynopus nicoleae-are junior synonyms of Phrynopus tribulosus. Using X-ray computed tomography (CT) imaging, we demonstrate that the absence of external hearing structures is associated with complete loss of the auditory skeletal elements (columella) in at least one member of the genus. We mapped the tympanum condition on to a species tree to infer whether the loss of hearing structures took place once or multiple times. We also assessed whether tympanum condition, body size, and body shape are associated with the elevational distribution and habitat use. We identified a single evolutionary transition that involved the loss of both the tympanic membrane and tympanic annulus, which in turn is correlated with the absence of advertisement calls. We also identified several species pairs where one species inhabits the Andean grassland and the other montane forest. When accounting for phylogenetic relatedness among species, we detected a significant pattern of increasing body size with increasing elevation. Additionally, species at higher elevations tend to develop shorter limbs, shorter head, and shorter snout than species living at lower elevations. Our findings strongly suggest a link between ecological divergence and morphological diversity of terrestrial breeding frogs living in montane gradients.
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Affiliation(s)
- Rudolf von May
- Museum of Zoology & Department of Ecology and Evolutionary Biology, University of Michigan-Ann Arbor, Ann Arbor, MI, United States of America.,Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, United States of America
| | - Edgar Lehr
- Department of Biology, Illinois Wesleyan University, Bloomington, IL, United States of America
| | - Daniel L Rabosky
- Museum of Zoology & Department of Ecology and Evolutionary Biology, University of Michigan-Ann Arbor, Ann Arbor, MI, United States of America
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18
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Womack MC, Fiero TS, Hoke KL. Trait independence primes convergent trait loss. Evolution 2018; 72:679-687. [PMID: 29383712 DOI: 10.1111/evo.13442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/21/2018] [Indexed: 01/24/2023]
Abstract
The repeated, independent evolution of traits (convergent evolution) is often attributed to shared environmental selection pressures. However, developmental dependencies among traits can limit the phenotypic variation available to selection and bias evolutionary outcomes. Here, we determine how changes in developmentally correlated traits may impact convergent loss of the tympanic middle ear, a highly labile trait within toads that currently lack adaptive explanation. The middle ear's lability could reflect evolutionary trade-offs with other skull features under selection, or the middle ear may evolve independently of the rest of the skull, allowing it to be modified by active or passive processes without pleiotropic trade-offs with other skull features. We compare the skulls of 55 species (39 eared, 16 earless) within the family Bufonidae, spanning six hypothesized independent middle ear transitions. We test whether shared or lineage-specific changes in skull shape distinguish earless species from eared species and whether earless skulls lack other late-forming skull bones. We find no evidence for pleiotropic trade-offs between the middle ear and other skull structures. Instead, middle ear loss in anurans may provide a rare example of developmental independence contributing to evolutionary lability of a sensory system.
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Affiliation(s)
- Molly C Womack
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia 20560
| | - Tyler S Fiero
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Kim L Hoke
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523
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