@article {58409, title = {Morphological Evidence for the Sensitivity of the Ear Canal of Odontocetes as shown by Immunohistochemistry and Transmission Electron Microscopy}, year = {2020}, abstract = {

Tthe function of the external ear canal in cetaceans is still under debate and its morphology is largely\ unknown. Immunohistochemical (IHC) analyses using antibodies specific for nervous tissue (anti-S100, anti-NSE, anti-NF, and anti-PGP 9.5), together with transmission electron microscopy (TEM) and various histological techniques, were carried out to investigate the peripheral nervous system of the ear canals of several species of toothed whales and terrestrial cetartiodactyla. this study highlights the innervation of the ear canal with the presence of lamellar corpuscles over its entire course, and their absence in all studied terrestrial mammals. Each corpuscle consisted of a central axon, surrounded\ by lamellae of Schwann receptor cells, surrounded by a thin cellular layer, as shown by IHC and TEM. These findings indicate that the corpuscles are mechanoreceptors that resemble the inner core of Pacinian corpuscles without capsule or outer core, and were labelled as simple lamellar corpuscles. They form part of a sensory system that may represent a unique phylogenetic feature of cetaceans, and an evolutionary adaptation to life in the marine environment. Although the exact function of the ear canal is not fully clear, we provide essential knowledge and a preliminary hypothetical deviation on its function as a unique sensory organ.

}, doi = {10.1038/s41598-020-61170-4}, url = {http://www.nature.com/articles/s41598-020-61170-4}, author = {De Vreese, Steffen and Andr{\'e}, Michel and Cozzi, Bruno and Centelleghe, Cinzia and van der Schaar, Mike and Mazzariol, Sandro} } @article {57998, title = {Dolphin whistle repertoires around S{\~a}o Miguel (Azores): Are you common or spotted?}, year = {2020}, abstract = {

Short-beaked common dolphins (Delphinus delphis) and Atlantic spotted dolphins (Stenella frontalis) are both common in the Azores archipelago during summer. Because both species are sympatric, at least in part of their range, they may use acoustic features to recognize conspecifics and maintain school cohesion throughout their different activities. Delphinid whistles were recorded with a 96-kHz sampling rate using towed hydrophone system during surveys held in summer of 2013 and 2014 around S\ão Miguel Island (Azores, Portugal). A total of 256 whistles attributed to either short-beaked common dolphin (n = 133) or Atlantic spotted dolphin (n = 123) were selected and processed with a contour extraction software. Elementary statistical analysis showed that duration, frequency and slope variables were significantly different for both species, although in most cases their range overlapped. We performed a discriminant analysis to test species classification: the dataset was randomly split into one calibration subset (186 whistles) and one validation subset (70 whistles). The discriminant analysis retained four variables (global slope, duration, minimal and final frequencies) as useful for classification. The discriminant function resulted in correct classification rates of 78.5\% (calibration subset) and 81.4\% (validation subset). Common dolphin whistles were better classified than Atlantic spotted dolphin whistles (83.4\% and 74.8\%) respectively. This study shows that reliable species identification can be achieved for common and spotted dolphins using their whistle repertoire characteristics.

}, doi = {10.1016/j.apacoust.2019.107169}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003682X16305394}, author = {Gannier, Alexandre and Fuchs, Sandra and Gannier, Adrien and Fernandez, Marc and Azevedo, Jos{\'e} M.N.} } @article {53288, title = {Clymene dolphin ( Stenella clymene) whistles in the Southwest Atlantic Ocean}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1952 - 1952}, abstract = {

The Clymene dolphin despite being endemic for the Atlantic Ocean continues to be the least known species in the genus Stenella without available information on their vocal repertoire in Brazilian waters. Data were obtained during mitigation and monitoring work required by IBAMA under the federal environmental licensing as conditions of the license 108/16 for the 3D seismic survey in Par\á/Maranh\ão Sedimentary Basin process 02022.000015/2014. The species record was performed onboard the vessel Polarcus Alima with a Mseis (Night Hawk III) four-element towed array passing signals to a digital M-Audio, recording at 96 kHz/16bits. During visual and acoustic monitoring with the air-guns off, a group of approximate 80 dolphins were sighted and recorded on May 8th, 2016 (00o38\’00\” N, 44o45\’25\” O) at 3,425 m depth. The wav-files were analyzed through the spectrogram configured as DFT 2048 samples, 70\% overlap and Hamming window of 1024 points generated by software Raven Pro 1.5. The results of 14 min recording allowed the extraction of 257 whistles. Minimum frequencies ranged from 5.20 kHz to 15.92 kHz (mean\ =\ 10.99 kHz); maximum frequencies ranged from 7.72 kHz to 28.04 kHz (mean\ =\ 16.16 kHz); whistle duration ranged from 0.01 s to 1.52 s (mean\ =\ 0.43 s). These results are important since they represent the first acoustic record of Clymene dolphins in Brazil.

}, issn = {0001-4966}, doi = {10.1121/1.5068534}, url = {http://asa.scitation.org/doi/10.1121/1.5068534}, author = {Juliana R. Moron and Alves, Luiz Cl{\'a}udio P. and de Assis, Carla Viviane and Garcia, Felipe C. and Andriolo, Artur} } @article {47326, title = {Successful suction-cup tagging of a small delphinid species, Stenella attenuata: Insights into whistle characteristics}, journal = {Marine Mammal Science}, year = {2016}, month = {Jan-12-2016}, doi = {10.1111/mms.12376}, url = {http://doi.wiley.com/10.1111/mms.12376}, author = {Silva, Tammy L. and Laela S. Sayigh and Baird, Robin W.} } @article {47322, title = {Acoustic classification of dolphins in the California Current using whistles, echolocation clicks, and burst pulses}, journal = {Marine Mammal Science}, year = {2016}, month = {Jan-12-2016}, abstract = {

Passive acoustic monitoring of dolphins is limited by our ability to classify calls to species. Significant overlap in call characteristics among many species, combined with a wide range of call types and acoustic behavior, makes classification of calls to species challenging. Here, we introduce BANTER, a compound acoustic classification method for dolphins that utilizes information from all call types produced by dolphins rather than a single call type, as has been typical for acoustic classifiers. Output from the passive acoustic monitoring software, PAMGuard, was used to create independent classifiers for whistles, echolocation clicks, and burst pulses, which were then merged into a final, compound classifier for each species. Classifiers for five species found in the California Current ecosystem were trained and tested using 153 single-species acoustic events recorded during a 4.5 mo combined visual and acoustic shipboard cetacean survey off the west coast of the United States. Correct classification scores for individual species ranged from 71\% to 92\%, with an overall correct classification score of 84\% for all five species. The conceptual framework of this approach easily lends itself to other species and study areas as well as to noncetacean taxa.

}, keywords = {acoustics, burst pulses, classification, delphinids, dolphins, echolocation clicks, whistles}, doi = {10.1111/mms.12381}, url = {http://doi.wiley.com/10.1111/mms.12381}, author = {Rankin, Shannon and Archer, Frederick and Keating, Jennifer L. and Oswald, Julie N. and Oswald, Michael and Curtis, Alex and Barlow, Jay} }