Raising your voice: evolution of narrow-band high-frequency signals in toothed whales (Odontoceti)

Galatius, Anders; Olsen, Morten Tange; Steeman, Mette Elstrup; Racicot, Rachel A.; Bradshaw, Catherine; Kyhn, Line A.; Miller, Lee A.

doi:10.1093/biolinnean/bly194

Cited by 46 publications

(47 citation statements)

References 53 publications

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“…3 ) [ 26 ]. This low asymmetry is likely tied to their relatively low peak-power biosonar [ 22 , 64 ]. Further, many descriptions of eurhinodelphinids have suggested that their crania are only slightly asymmetric [ 32 , 65 ], as is supported here (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Monodon remains the most asymmetric skull in the sample, even when the rostrum is removed (Σ ρ spec = 0.472) which rules out the possibility that the asymmetric tusk and residual teeth may be skewing the overall Σ ρ spec (see below for details). Their unique sound repertoire (narrowband structured, NBS) is ideal for projecting and receiving signals in icy, shallow waters, where the animals can detect targets in high levels of ambient noise and backscatter [ 44 ] (Additional file 1 : Table S8 [ 24 , 40 – 42 , 45 – 54 , 64 , 70 – 72 ]). Jumps detected in the delphinids all belong to the subfamily Globicephalinae (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…By regime, we mean a particular condition or process that may be underlying the observed patterns of cranial asymmetry. We further fitted a ‘frequency echolocation’ model (model: ‘echo-freq’) (Table 4 ; Additional file 1 : Table S8 [ 40 – 42 , 45 – 54 , 64 , 70 – 72 ]). This study is not a specialist analysis of acoustics (nor behaviours affecting acoustics) in cetaceans, and we use these values to indicate potential drivers for the evolution of cranial asymmetry.…”

Section: Methodsmentioning

confidence: 99%

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Wonky whales: the evolution of cranial asymmetry in cetaceans

et al. 2020

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Background Unlike most mammals, toothed whale (Odontoceti) skulls lack symmetry in the nasal and facial (nasofacial) region. This asymmetry is hypothesised to relate to echolocation, which may have evolved in the earliest diverging odontocetes. Early cetaceans (whales, dolphins, and porpoises) such as archaeocetes, namely the protocetids and basilosaurids, have asymmetric rostra, but it is unclear when nasofacial asymmetry evolved during the transition from archaeocetes to modern whales. We used three-dimensional geometric morphometrics and phylogenetic comparative methods to reconstruct the evolution of asymmetry in the skulls of 162 living and extinct cetaceans over 50 million years. Results In archaeocetes, we found asymmetry is prevalent in the rostrum and also in the squamosal, jugal, and orbit, possibly reflecting preservational deformation. Asymmetry in odontocetes is predominant in the nasofacial region. Mysticetes (baleen whales) show symmetry similar to terrestrial artiodactyls such as bovines. The first significant shift in asymmetry occurred in the stem odontocete family Xenorophidae during the Early Oligocene. Further increases in asymmetry occur in the physeteroids in the Late Oligocene, Squalodelphinidae and Platanistidae in the Late Oligocene/Early Miocene, and in the Monodontidae in the Late Miocene/Early Pliocene. Additional episodes of rapid change in odontocete skull asymmetry were found in the Mid-Late Oligocene, a period of rapid evolution and diversification. No high-probability increases or jumps in asymmetry were found in mysticetes or archaeocetes. Unexpectedly, no increases in asymmetry were recovered within the highly asymmetric ziphiids, which may result from the extreme, asymmetric shape of premaxillary crests in these taxa not being captured by landmarks alone. Conclusions Early ancestors of living whales had little cranial asymmetry and likely were not able to echolocate. Archaeocetes display high levels of asymmetry in the rostrum, potentially related to directional hearing, which is lost in early neocetes—the taxon including the most recent common ancestor of living cetaceans. Nasofacial asymmetry becomes a significant feature of Odontoceti skulls in the Early Oligocene, reaching its highest levels in extant taxa. Separate evolutionary regimes are reconstructed for odontocetes living in acoustically complex environments, suggesting that these niches impose strong selective pressure on echolocation ability and thus increased cranial asymmetry.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Wonky whales: the evolution of cranial asymmetry in cetaceans

et al. 2020

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“…Functional conclusions, for example, about hearing capabilities, cannot be drawn at this stage. Therefore, comprehensive CT-scan data of the cochlea are one of the essential basics (see Ekdale and Racicot, 2015;Ritsche et al, 2018) and are available so far in detail only for the living sperm whale (Davids et al, 2011) and, very recently, for Acrophyseter deinodon (Galatius et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

An unfamiliar physeteroid periotic (Cetacea: Odontoceti) from the German middle–late Miocene North Sea basin at Groß Pampau

Montañez-Rivera

Hampe

2020

Foss. Rec.

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Abstract. The Miocene mica clay locality of Groß Pampau, known for numerous and partly spectacular finds of marine mammals is becoming more and more a prominent site that bears the potential to resolve questions regarding taphonomic relationships and to interpret life communities of the ancient North Sea because of its rich faunal assemblage including invertebrates and other remains of various vertebrate organisms. In the present work we describe a right periotic of Physeteroidea with morphological characters so far unknown from other sperm whales. The periotics of the middle Miocene Aulophyseter morricei demonstrate the closest resemblance to the Groß Pampau specimen in their overall appearance and in the general arrangement and proportions of single structures, particularly of the anterior process and pars cochlearis. A great similarity is also documented with periotics of the living sperm whale, Physeter macrocephalus, especially regarding the shape and disposition of the anterior process and the bony element located dorsally to the accessory ossicle. Kogiid periotics differ strongly from that of the Groß Pampau specimen by having an inflated and short anterior process and, typically, three well-defined spines on it. A new taxonomic naming of the Groß Pampau periotic is not appropriate at this stage, although it might demonstrate the existence of a so-far undescribed physeteroid species. Additionally, its systematic position remains yet unclear and it is unknown at this point if it could belong to Hoplocetus ritzi, another physeterid, whose fragments were discovered in the same locality, or to another, already-described taxon, of which the periotic is still unknown.

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“…A click train is loosely defined as "any series of clicks separated by gradually or cyclically changing inter-click interval suggesting a unit during an echolocation event or a communication signal" (Koschinski, Diederichs, and Amundin 2008). Other odontocetes that produce NBHF clicks are all the porpoises (Phocoenidae), some dolphins of the Lissodelphininae subfamilily, pygmy and dwarf sperm whales (Kogiidae), and the river dolphin Pontoporia blainvillei (Galatius et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Porpoise click classifier (PorCC): A high-accuracy classifier to study harbour porpoises (Phocoena phocoena) in the wild

Cosentino

Guarato

Tougaard

et al. 2019

The Journal of the Acoustical Society of America

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Harbour porpoises are well-suited for passive acoustic monitoring (PAM) as they produce highly stereotyped narrow-band high-frequency (NBHF) echolocation clicks. PAM systems must be coupled with a classification algorithm to identify the signals of interest. Here, we present a harbour porpoise click classifier (PorCC) developed in MATLAB, which uses the coefficients of two logistic regression models in a decision-making pathway to assign candidate signals to one of three categories: high-quality clicks (HQ), low-quality clicks (LQ), or high-frequency noise (N). The receiver operating characteristics of PorCC was compared to that of PAMGuard's Porpoise Click Detector/Classifier Module. PorCC outperformed PAMGuard's classifier achieving higher hit rates (correctly classified clicks) and lower false alarm levels (noise classified as HQ or LQ clicks). Additionally, the detectability index (d') for HQ clicks for PAMGuard was 2.2 (overall d' = 2.0) versus 4.1 for PorCC (overall d' = 3.4). PorCC classification algorithm is a rapid and highly accurate method to classify NBHF clicks, which could be applied for real time monitoring, as well as to study harbour porpoises, and potentially other NBHF species, throughout their distribution range from data collected using towed hydrophones or static recorders. Moreover, PorCC is suitable for studies of acoustic communication of porpoises.

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Raising your voice: evolution of narrow-band high-frequency signals in toothed whales (Odontoceti)

Cited by 46 publications

References 53 publications

Wonky whales: the evolution of cranial asymmetry in cetaceans

Wonky whales: the evolution of cranial asymmetry in cetaceans

An unfamiliar physeteroid periotic (Cetacea: Odontoceti) from the German middle–late Miocene North Sea basin at Groß Pampau

Porpoise click classifier (PorCC): A high-accuracy classifier to study harbour porpoises (Phocoena phocoena) in the wild

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