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

Fossil Record ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 33-45 ◽  
Author(s):  
Indira S. Ritsche ◽  
Julia M. Fahlke ◽  
Frank Wieder ◽  
André Hilger ◽  
Ingo Manke ◽  
...  
Keyword(s):  
Inner Ear ◽  
Shape Analysis ◽  
Late Miocene ◽  
High Frequency ◽  
Middle Miocene ◽  
Low Frequencies ◽  
Baleen Whales ◽  
Extinct Species ◽  
Cranial Shape

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.

scholarly journals New Paratethyan dwarf baleen whales mark the origin of cetotheres

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5800 ◽  
Author(s):  
Pavel Gol'din
Keyword(s):  
Late Miocene ◽  
Middle Miocene ◽  
Sensu Stricto ◽  
Anterior Lobe ◽  
New Genus And Species ◽  
Facial Bones ◽  
Baleen Whales ◽  
The Family ◽  
Juvenile Specimen ◽  
Stepwise Evolution

Background Family Cetotheriidae sensu stricto and several closely related taxa comprise the Cetotherioidea and represent a lineage of Neogene baleen whales that includes the smallest edentulous baleen whales in Earth history. Most of known cetotheriids came from the Late Miocene to Quaternary, and the earliest records from the latest Middle Miocene. The Paratethys region shows a great diversity of Middle to Late Miocene cetotheriids. That includes nominative taxon of the family, Cetotherium rathkii, and this suggests that the earliest cetotheriids may have lived in that region. Materials and methods Here, Ciuciulea davidi, a new genus and species from the Middle Miocene of southeastern Europe, is described as the chronologically earliest and earliest diverging member of Cetotheriidae. Also, a new specimen of Otradnocetus, a basal Cetotherioidea sensu Gol’din & Steeman, 2015 is identified from the Late Miocene deposits of Caucasus and compared with Otradnocetus virodovi from the Middle Miocene of the same region. Results and discussion Ciuciulea davidi is a dwarf whale displaying primitive traits: posterior ends of facial bones forming a single transverse line, a narrow occipital shield, and a relatively long interparietal region. Meanwhile, it shares some cetotheriid apomorphies: posteriorly telescoped wedge-shaped facial bones and an ovoid tympanic bulla with shallow lateral and medial furrows, a short anterior lobe and a short sigmoid process. Phylogenetic analysis suggests that Parietobalaena and Otradnocetus are branches diverging before the clade Cetotheriidae + Neobalaenidae. This is confirmed by the stepwise evolution of the anatomy of the squamosal, mandible, and ear bones across these groups. The re-described juvenile specimen of Otradnocetus differs from O. virodovi in the more primitive anatomy of the mandible and the autapomorphic anatomy of the humerus. Records of the earliest cetotheriids and related taxa in the Paratethys support the idea that this could be the region where Cetotheriidae evolved before their worldwide dispersal and radiation.

scholarly journals Low-frequency hearing preceded the evolution of giant body size and filter feeding in baleen whales

2017 ◽  
Vol 284 (1848) ◽  
pp. 20162528 ◽  
Author(s):  
Travis Park ◽  
Alistair R. Evans ◽  
Stephen J. Gallagher ◽  
Erich M. G. Fitzgerald
Keyword(s):  
Body Size ◽  
High Frequency ◽  
Low Frequency ◽  
Frequency Range ◽  
Range Estimation ◽  
Filter Feeding ◽  
Low Frequencies ◽  
Baleen Whales ◽  
Lack Of Information ◽  
The Usa

Living baleen whales (mysticetes) produce and hear the lowest-frequency (infrasonic) sounds among mammals. There is currently debate over whether the ancestor of crown cetaceans (Neoceti) was able to detect low frequencies. However, the lack of information on the most archaic fossil mysticetes has prevented us from determining the earliest evolution of their extreme acoustic biology. Here, we report the first anatomical analyses and frequency range estimation of the inner ear in Oligocene (34–23 Ma) fossils of archaic toothed mysticetes from Australia and the USA. The cochlear anatomy of these small fossil mysticetes resembles basilosaurid archaeocetes, but is also similar to that of today's baleen whales, indicating that even the earliest mysticetes detected low-frequency sounds, and lacked ultrasonic hearing and echolocation. This suggests that, in contrast to recent research, the plesiomorphic hearing condition for Neoceti was low frequency, which was retained by toothed mysticetes, and the high-frequency hearing of odontocetes is derived. Therefore, the low-frequency hearing of baleen whales has remained relatively unchanged over the last approximately 34 Myr, being present before the evolution of other signature mysticete traits, including filter feeding, baleen and giant body size.

scholarly journals Earless toads sense low frequencies but miss the high notes

2017 ◽  
Vol 284 (1864) ◽  
pp. 20171670 ◽  
Author(s):  
Molly C. Womack ◽  
Jakob Christensen-Dalsgaard ◽  
Luis A. Coloma ◽  
Juan C. Chaparro ◽  
Kim L. Hoke
Keyword(s):  
High Frequency ◽  
Species Differences ◽  
Low Frequency ◽  
Auditory Brainstem ◽  
Low Frequencies ◽  
Hearing Sensitivity ◽  
Sensory Pathways ◽  
Airborne Sound ◽  
Vibrational Sensitivity ◽  
Species Specific

Sensory losses or reductions are frequently attributed to relaxed selection. However, anuran species have lost tympanic middle ears many times, despite anurans' use of acoustic communication and the benefit of middle ears for hearing airborne sound. Here we determine whether pre-existing alternative sensory pathways enable anurans lacking tympanic middle ears (termed earless anurans) to hear airborne sound as well as eared species or to better sense vibrations in the environment. We used auditory brainstem recordings to compare hearing and vibrational sensitivity among 10 species (six eared, four earless) within the Neotropical true toad family (Bufonidae). We found that species lacking middle ears are less sensitive to high-frequency sounds, however, low-frequency hearing and vibrational sensitivity are equivalent between eared and earless species. Furthermore, extratympanic hearing sensitivity varies among earless species, highlighting potential species differences in extratympanic hearing mechanisms. We argue that ancestral bufonids may have sufficient extratympanic hearing and vibrational sensitivity such that earless lineages tolerated the loss of high frequency hearing sensitivity by adopting species-specific behavioural strategies to detect conspecifics, predators and prey.

scholarly journals Hearing from the ocean and into the river: the evolution of the inner ear of Platanistoidea (Cetacea: Odontoceti)

Paleobiology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Mariana Viglino ◽  
Maximiliano Gaetán ◽  
Mónica R. Buono ◽  
R. Ewan Fordyce ◽  
Travis Park
Keyword(s):  
Inner Ear ◽  
High Frequency ◽  
Sound Production ◽  
Marine Species ◽  
Late Oligocene ◽  
Evolutionary Patterns ◽  
Ear Morphology ◽  
Cochlear Morphology ◽  
First Time ◽  
Hearing Abilities

Abstract The inner ear of the two higher clades of modern cetaceans (Neoceti) is highly adapted for hearing infrasonic (mysticetes) or ultrasonic (odontocetes) frequencies. Within odontocetes, Platanistoidea comprises a single extant riverine representative, Platanista gangetica, and a diversity of mainly extinct marine species from the late Oligocene onward. Recent studies drawing on features including the disparate tympanoperiotic have not yet provided a consensus phylogenetic hypothesis for platanistoids. Further, cochlear morphology and evolutionary patterns have never been reported. Here, we describe for the first time the inner ear morphology of late Oligocene–early Miocene extinct marine platanistoids and their evolutionary patterns. We initially hypothesized that extinct marine platanistoids lacked a specialized inner ear like P. gangetica and thus, their morphology and inferred hearing abilities were more similar to those of pelagic odontocetes. Our results reveal there is no “typical” platanistoid cochlear type, as the group displays a disparate range of cochlear anatomies, but all are consistent with high-frequency hearing. Stem odontocete Prosqualodon australis and platanistoid Otekaikea huata present a tympanal recess in their cochlea, of yet uncertain function in the hearing mechanism in cetaceans. The more basal morphology of Aondelphis talen indicates it had lower high-frequency hearing than other platanistoids. Finally, Platanista has the most derived cochlear morphology, adding to evidence that it is an outlier within the group and consistent with a >9-Myr-long separation from its sister genus Zarhachis. The evolution of a singular sound production morphology within Platanistidae may have facilitated the survival of Platanista to the present day.

Middle Miocene (∼14 Ma) and Late Miocene (∼6 Ma) Paleogeographic Boundary Conditions

2021 ◽  
Author(s):  
Zhilin He ◽  
Zhongshi Zhang ◽  
Zhengtang Guo ◽  
Christopher R. Scotese ◽  
Chenglong Deng
Keyword(s):  
Boundary Conditions ◽  
Late Miocene ◽  
Middle Miocene

A new argyrolagoid (Mammalia: Marsupialia) from the middle Miocene of Bolivia

1988 ◽  
Vol 62 (3) ◽  
pp. 463-467 ◽  
Author(s):  
Villarroel A. Carlos ◽  
Larry G. Marshall
Keyword(s):  
South America ◽  
Late Miocene ◽  
Adaptive Radiation ◽  
Middle Miocene ◽  
Northwest Argentina ◽  
The Family ◽  
Size And Structure

A new argyrolagoid marsupial, Hondalagus altiplanensis n. gen., n. sp., from the middle Miocene (Santacrucian–Friasian) age locality of Quebrada Honda in southernmost Bolivia represents the smallest and most specialized member of the family Argyrolagidae known. The lower molars are hypselodont and lack vertical grooves labially and lingually, and M4 is greatly reduced relative to M3. In overall size and structure, H. altiplanensis compares best with Microtragulus catamarcensis (Kraglievich, 1931) from rocks of late Miocene (Huayquerian) age in northwest Argentina. Hondalagus altiplanensis demonstrates that the adaptive radiation of argyrolagoids was much greater than previously envisioned, and that generic differentiation of known taxa occurred no later than early–middle Miocene time in South America.

scholarly journals The Estimation of Hydrometeor Profiles from Wideband Microwave Observations

2000 ◽  
Vol 39 (10) ◽  
pp. 1645-1656 ◽  
Author(s):  
Gail M. Skofronick-Jackson ◽  
James R. Wang
Keyword(s):  
High Frequency ◽  
Cloud Water ◽  
Tropical Ocean ◽  
Low Frequencies ◽  
High Frequencies ◽  
Atmospheric Research ◽  
Brightness Temperatures ◽  
Microphysical Properties ◽  
Ice Microphysics ◽  
Updraft Region

Abstract Profiles of the microphysical properties of clouds and rain cells are essential in many areas of atmospheric research and operational meteorology. To enhance the understanding of the nonlinear and underconstrained relationships between cloud and hydrometeor microphysical profiles and passive microwave brightness temperatures, estimations of cloud profiles for an anvil region, a convective region, and an updraft region of an oceanic squall were performed. The estimations relied on comparisons between radiative transfer calculations of incrementally estimated microphysical profiles and concurrent dual-altitude wideband brightness temperatures from the 22 February 1993 flight during the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment. The wideband observations (10–220 GHz) are necessary for estimating cloud profiles reaching up to 20 km. The low frequencies enhance the rain and cloud water profiles, and the high frequencies are required to detail the higher-altitude ice microphysics. A microphysical profile was estimated for each of the three regions of the storm. Each of the three estimated profiles produced calculated brightness temperatures within ∼10 K of the observations. A majority of the total iterative adjustments were to the estimated profile’s frozen hydrometeor characteristics and were necessary to match the high-frequency calculations with the observations. This requirement indicates a need to validate cloud-resolving models using high frequencies. Some difficulties matching the 37-GHz observation channels on the DC-8 and ER-2 aircraft with the calculations simulated at the two aircraft heights (∼11 km and 20 km, respectively) were noted, and potential causes were presented.

scholarly journals The dual-slope conversion improvement

2014 ◽  
Vol 11 (3) ◽  
pp. 351-363
Author(s):  
Radojle Radetic ◽  
Marijana Pavlov-Kagadejev ◽  
Nikola Milivojevic
Keyword(s):  
High Frequency ◽  
Frequency Noise ◽  
Good Resolution ◽  
Practical Realization ◽  
Digital Conversion ◽  
Low Frequencies ◽  
Analog To Digital ◽  
High Frequency Noise ◽  
Low Input ◽  
Analog To Digital Conversion

The dual-slope ADC (DSADC) is a type of analog-to-digital conversion with low input bandwidths. It is pretty slow, but its ability to reject high-frequency noise and fixed low frequencies such as 50 Hz or 60 Hz makes it useful in noisy industrial environments and applications. It provides very good resolution. For the practical measurements in the Institutes laboratory an instrument is designed and realized. The base DSADC method is used, but improved by multiple conversions to make the measuring more precise and the time shorter. The special attention is paid to the problems occurred in practical realization and the way to overcome them. The paper describes the proposed and applied solutions, functional principles and achieved performances of the realized instrument.

scholarly journals Novel Negative Capacitance and Conductance in All Temperatures and Voltages of Au/CNTs/n-Si/Al at Low and High Frequencies

2021 ◽  
Author(s):  
A. Ashery ◽  
Samia Gad ◽  
A. E.H. Gaballah ◽  
G. M. Turky
Keyword(s):  
Carbon Nanotube ◽  
High Frequency ◽  
Series Resistance ◽  
Negative Capacitance ◽  
Donor Concentration ◽  
Low Frequencies ◽  
High Frequencies ◽  
Depletion Width ◽  
Density Surface ◽  
P Type

Abstract The structure of carbon nanotube CNTs functioning as p-type material deposited over n-type silicon to produce heterojunction of Au/CNTs/n-Si/Al is presented in this study.This work explored the capacitance and conductance at various frequencies, temperatures, and voltages, the novelty here is that negative capacitance and conductance were observed at high frequencies in all temperatures and voltages, whereas capacitance appeared at both high and low frequencies, such as (2x107,1x107,1x102,10) Hz. At high-frequency f = 2x107 Hz, the capacitance raises while the conductance decreases; at all temperatures and voltages, the capacitance and conductance exhibit the same behavior at particular frequencies such as 1x106,1x105,1x104,1x103Hz, however their behavior differs at 2x107,1x107, 1x102 and 10Hz. Investigating the reverse square capacitance with voltage yielded the energy fermi (Ef), density surface of states (Nss), depletion width (Wd), barrier height, series resistance, and donor concentration (Nd)

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