Journal articles: 'Whales Whales Whales Cetacea Cetacea Cetacea'

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O'Leary, Maureen A., and Mark D. Uhen. "The time of origin of whales and the role of behavioral changes in the terrestrial-aquatic transition." Paleobiology 25, no. 4 (1999): 534–56. http://dx.doi.org/10.1017/s0094837300020376.

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Addition of the recently discovered fossil Nalacetus to a phylogenetic analysis of basicranial, cranial, dental, postcranial, and soft morphological characters reveals that it is the most basal cetacean, and that mesonychians form the monophyletic sister group to Cetacea. The molars of Nalacetus elucidate transformations in dental morphology that occurred early in the cetacean radiation and clarify certain derived differences in molar cusp position between cetaceans and the extinct clade, Mesonychia, hypothesized to be their sister taxon. Nalacetus and other archaic cetaceans share derived vertically elongate shearing facets on the lower molars. Applying the Extant Phylogenetic Bracket, we advance the hypothesis that these facets are an osteological correlate of aquatic predation. Our functional interpretation of this character and its distribution within Cetacea indicates that a behavioral change in tooth use characterized the origin of the clade. Comparison of the transformation of this dental character with that of the cetacean pelvis indicates that a change in tooth use (feeding behavior) occurred before loss of the ability to engage in terrestrial locomotion.The most parsimonious phylogenetic hypothesis presented here has a significant fit with the stratigraphic record as determined by the Manhattan Stratigraphic Measure, which is corroborated by retention indices of stratigraphic data. Ghost lineages necessitated by the phylogenetic hypothesis extend the stratigraphic range of Cetacea into the middle Paleocene (Torrejonian), ten million years earlier than the oldest cetacean fossil currently known. Primitive features of Nalacetus, the large number of synapomorphies diagnosing Cetacea, and the implied ghost lineage suggest that the early cetacean radiation was much more extensive than has been previously recognized.

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RAVIKANT, VADLAMANI, and S. BAJPAI. "Strontium isotope evidence for the age of Eocene fossil whales of Kutch, western India." Geological Magazine 147, no. 3 (2010): 473–77. http://dx.doi.org/10.1017/s0016756810000099.

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AbstractThe Indian subcontinent is widely considered to be the birthplace of whales (Cetacea), and the middle Eocene Harudi Formation of Kutch has long been known to be a major source of early whales. The Kutch cetaceans are of critical importance in understanding the evolutionary transition of whales from land to sea. Strontium isotope analysis of marine biogenic carbonates from the Harudi Formation was conducted to obtain a numerical age of the whale-bearing strata. Although the measured 87Sr/86Sr ratios (0.707742 to 0.707764) correspond to two distinct age clusters of 46–47.5 Ma or 41–42.5 Ma, we prefer the latter, late Lutetian, age cluster.

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Kulemzina, Anastasia I., Anastasia A. Proskuryakova, Violetta R. Beklemisheva, Natalia A. Lemskaya, Polina L. Perelman, and Alexander S. Graphodatsky. "Comparative Chromosome Map and Heterochromatin Features of the Gray Whale Karyotype (Cetacea)." Cytogenetic and Genome Research 148, no. 1 (2016): 25–34. http://dx.doi.org/10.1159/000445459.

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Cetacean karyotypes possess exceptionally stable diploid numbers and highly conserved chromosomes. To date, only toothed whales (Odontoceti) have been analyzed by comparative chromosome painting. Here, we studied the karyotype of a representative of baleen whales, the gray whale (Eschrichtius robustus, Mysticeti), by Zoo-FISH with dromedary camel and human chromosome-specific probes. We confirmed a high degree of karyotype conservation and found an identical order of syntenic segments in both branches of cetaceans. Yet, whale chromosomes harbor variable heterochromatic regions constituting up to a third of the genome due to the presence of several types of repeats. To investigate the cause of this variability, several classes of repeated DNA sequences were mapped onto chromosomes of whale species from both Mysticeti and Odontoceti. We uncovered extensive intrapopulation variability in the size of heterochromatic blocks present in homologous chromosomes among 3 individuals of the gray whale by 2-step differential chromosome staining. We show that some of the heteromorphisms observed in the gray whale karyotype are due to distinct amplification of a complex of common cetacean repeat and heavy satellite repeat on homologous autosomes. Furthermore, we demonstrate localization of the telomeric repeat in the heterochromatin of both gray and pilot whale (Globicephala melas, Odontoceti). Heterochromatic blocks in the pilot whale represent a composite of telomeric and common repeats, while heavy satellite repeat is lacking in the toothed whale consistent with previous studies.

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Lisney, Thomas J., and Shaun P. Collin. "Retinal Topography in Two Species of Baleen Whale (Cetacea: Mysticeti)." Brain, Behavior and Evolution 92, no. 3-4 (2018): 97–116. http://dx.doi.org/10.1159/000495285.

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Little is known about the visual systems of large baleen whales (Mysticeti: Cetacea). In this study, we investigate eye morphology and the topographic distribution of retinal ganglion cells (RGCs) in two species of mysticete, Bryde’s whale (Balaenoptera edeni) and the humpback whale (Megaptera novaeanglia). Both species have large eyes characterised by a thickened cornea, a heavily thickened sclera, a highly vascularised fibro-adipose bundle surrounding the optic nerve at the back of the eye, and a reflective blue-green tapetum fibrosum. Using stereology and retinal whole mounts, we estimate a total of 274,268 and 161,371 RGCs in the Bryde’s whale and humpback whale retinas, respectively. Both species have a similar retinal topography, consisting of nasal and temporal areas of high RGC density, suggesting that having higher visual acuity in the anterior and latero-caudal visual fields is particularly important in these animals. The temporal area is larger in both species and contains the peak RGC densities (160 cells mm–2 in the humpback whale and 200 cells mm–2 in Bryde’s whale). In the Bryde’s whale retina, the two high-density areas are connected by a weak centro-ventral visual streak, but such a specialisation is not evident in the humpback whale. Measurements of RGC soma area reveal that although the RGCs in both species vary substantially in size, RGC soma area is inversely proportional to RGC density, with cells in the nasal and temporal high-density areas being relatively more homogeneous in size compared to the RGCs in the central retina and the dorsal and ventral retinal periphery. Some of the RGCs were very large, with soma areas of over 2,000 µm2. Using peak RGC density and eye axial diameter (Bryde’s whale: 63.5 mm; humpback whale: 48.5 mm), we estimated the peak anatomical spatial resolving power in water to be 4.8 cycles/degree and 3.3 cycles/degree in the Bryde’s whale and the humpback whale, respectively. Overall, our findings for these two species are very similar to those reported for other species of cetaceans. This indicates that, irrespective of the significant differences in body size and shape, behavioural ecology and feeding strategy between mysticetes and odontocetes (toothed whales), cetacean eyes are adapted to vision in dim light and adhere to a common “bauplan” that evolved prior to the divergence of the two cetacean parvorders (Odontoceti and Mysticeti) over 30 million years ago.

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McGowen, Michael R., Georgia Tsagkogeorga, Sandra Álvarez-Carretero, et al. "Phylogenomic Resolution of the Cetacean Tree of Life Using Target Sequence Capture." Systematic Biology 69, no. 3 (2019): 479–501. http://dx.doi.org/10.1093/sysbio/syz068.

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Abstract The evolution of cetaceans, from their early transition to an aquatic lifestyle to their subsequent diversification, has been the subject of numerous studies. However, although the higher-level relationships among cetacean families have been largely settled, several aspects of the systematics within these groups remain unresolved. Problematic clades include the oceanic dolphins (37 spp.), which have experienced a recent rapid radiation, and the beaked whales (22 spp.), which have not been investigated in detail using nuclear loci. The combined application of high-throughput sequencing with techniques that target specific genomic sequences provide a powerful means of rapidly generating large volumes of orthologous sequence data for use in phylogenomic studies. To elucidate the phylogenetic relationships within the Cetacea, we combined sequence capture with Illumina sequencing to generate data for $\sim $3200 protein-coding genes for 68 cetacean species and their close relatives including the pygmy hippopotamus. By combining data from $&gt;$38,000 exons with existing sequences from 11 cetaceans and seven outgroup taxa, we produced the first comprehensive comparative genomic data set for cetaceans, spanning 6,527,596 aligned base pairs (bp) and 89 taxa. Phylogenetic trees reconstructed with maximum likelihood and Bayesian inference of concatenated loci, as well as with coalescence analyses of individual gene trees, produced mostly concordant and well-supported trees. Our results completely resolve the relationships among beaked whales as well as the contentious relationships among oceanic dolphins, especially the problematic subfamily Delphinidae. We carried out Bayesian estimation of species divergence times using MCMCTree and compared our complete data set to a subset of clocklike genes. Analyses using the complete data set consistently showed less variance in divergence times than the reduced data set. In addition, integration of new fossils (e.g., Mystacodon selenensis) indicates that the diversification of Crown Cetacea began before the Late Eocene and the divergence of Crown Delphinidae as early as the Middle Miocene. [Cetaceans; phylogenomics; Delphinidae; Ziphiidae; dolphins; whales.]

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Whitehead, Hal. "Gene–culture coevolution in whales and dolphins." Proceedings of the National Academy of Sciences 114, no. 30 (2017): 7814–21. http://dx.doi.org/10.1073/pnas.1620736114.

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Whales and dolphins (Cetacea) have excellent social learning skills as well as a long and strong mother–calf bond. These features produce stable cultures, and, in some species, sympatric groups with different cultures. There is evidence and speculation that this cultural transmission of behavior has affected gene distributions. Culture seems to have driven killer whales into distinct ecotypes, which may be incipient species or subspecies. There are ecotype-specific signals of selection in functional genes that correspond to cultural foraging behavior and habitat use by the different ecotypes. The five species of whale with matrilineal social systems have remarkably low diversity of mtDNA. Cultural hitchhiking, the transmission of functionally neutral genes in parallel with selective cultural traits, is a plausible hypothesis for this low diversity, especially in sperm whales. In killer whales the ecotype divisions, together with founding bottlenecks, selection, and cultural hitchhiking, likely explain the low mtDNA diversity. Several cetacean species show habitat-specific distributions of mtDNA haplotypes, probably the result of mother–offspring cultural transmission of migration routes or destinations. In bottlenose dolphins, remarkable small-scale differences in haplotype distribution result from maternal cultural transmission of foraging methods, and large-scale redistributions of sperm whale cultural clans in the Pacific have likely changed mitochondrial genetic geography. With the acceleration of genomics new results should come fast, but understanding gene–culture coevolution will be hampered by the measured pace of research on the socio-cultural side of cetacean biology.

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Dungan, Sarah Z., and Belinda S. W. Chang. "Epistatic interactions influence terrestrial–marine functional shifts in cetacean rhodopsin." Proceedings of the Royal Society B: Biological Sciences 284, no. 1850 (2017): 20162743. http://dx.doi.org/10.1098/rspb.2016.2743.

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Like many aquatic vertebrates, whales have blue-shifting spectral tuning substitutions in the dim-light visual pigment, rhodopsin, that are thought to increase photosensitivity in underwater environments. We have discovered that known spectral tuning substitutions also have surprising epistatic effects on another function of rhodopsin, the kinetic rates associated with light-activated intermediates. By using absorbance spectroscopy and fluorescence-based retinal release assays on heterologously expressed rhodopsin, we assessed both spectral and kinetic differences between cetaceans (killer whale) and terrestrial outgroups (hippo, bovine). Mutation experiments revealed that killer whale rhodopsin is unusually resilient to pleiotropic effects on retinal release from key blue-shifting substitutions (D83N and A292S), largely due to a surprisingly specific epistatic interaction between D83N and the background residue, S299. Ancestral sequence reconstruction indicated that S299 is an ancestral residue that predates the evolution of blue-shifting substitutions at the origins of Cetacea. Based on these results, we hypothesize that intramolecular epistasis helped to conserve rhodopsin's kinetic properties while enabling blue-shifting spectral tuning substitutions as cetaceans adapted to aquatic environments. Trade-offs between different aspects of molecular function are rarely considered in protein evolution, but in cetacean and other vertebrate rhodopsins, may underlie multiple evolutionary scenarios for the selection of specific amino acid substitutions.

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McGowen, Michael R., Georgia Tsagkogeorga, Joseph Williamson, Phillip A. Morin, and and Stephen J. Rossiter. "Positive Selection and Inactivation in the Vision and Hearing Genes of Cetaceans." Molecular Biology and Evolution 37, no. 7 (2020): 2069–83. http://dx.doi.org/10.1093/molbev/msaa070.

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Abstract The transition to an aquatic lifestyle in cetaceans (whales and dolphins) resulted in a radical transformation in their sensory systems. Toothed whales acquired specialized high-frequency hearing tied to the evolution of echolocation, whereas baleen whales evolved low-frequency hearing. More generally, all cetaceans show adaptations for hearing and seeing underwater. To determine the extent to which these phenotypic changes have been driven by molecular adaptation, we performed large-scale targeted sequence capture of 179 sensory genes across the Cetacea, incorporating up to 54 cetacean species from all major clades as well as their closest relatives, the hippopotamuses. We screened for positive selection in 167 loci related to vision and hearing and found that the diversification of cetaceans has been accompanied by pervasive molecular adaptations in both sets of genes, including several loci implicated in nonsyndromic hearing loss. Despite these findings, however, we found no direct evidence of positive selection at the base of odontocetes coinciding with the origin of echolocation, as found in studies examining fewer taxa. By using contingency tables incorporating taxon- and gene-based controls, we show that, although numbers of positively selected hearing and nonsyndromic hearing loss genes are disproportionately high in cetaceans, counts of vision genes do not differ significantly from expected values. Alongside these adaptive changes, we find increased evidence of pseudogenization of genes involved in cone-mediated vision in mysticetes and deep-diving odontocetes.

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Ridgway, Sam H., Donald A. Carder, Tricia Kamolnick, Robert R. Smith, Carolyn E. Schlundt, and Wesley R. Elsberry. "Hearing and whistling in the deep sea: depth influences whistle spectra but does not attenuate hearing by white whales (Delphinapterus leucas) (Odontoceti, Cetacea)." Journal of Experimental Biology 204, no. 22 (2001): 3829–41. http://dx.doi.org/10.1242/jeb.204.22.3829.

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SUMMARY Hearing is attenuated in the aerial ear of humans and other land mammals tested in pressure chambers as a result of middle ear impedance changes that result from increased air density. We tested the hypothesis, based on recent middle ear models, that increasing the density of middle ear air at depth might attenuate whale hearing. Two white whales Delphinapterus leucas made dives to a platform at a depth of 5, 100, 200 or 300 m in the Pacific Ocean. During dives to station on the platform for up to 12 min, the whales whistled in response to 500 ms tones projected at random intervals to assess their hearing threshold at each depth. Analysis of response whistle spectra, whistle latency in response to tones and hearing thresholds showed that the increased hydrostatic pressure at depth changed each whale’s whistle response at depth, but did not attenuate hearing overall. The finding that whale hearing is not attenuated at depth suggests that sound is conducted through the head tissues of the whale to the ear without requiring the usual ear drum/ossicular chain amplification of the aerial middle ear. These first ever hearing tests in the open ocean demonstrate that zones of audibility for human-made sounds are just as great throughout the depths to which these whales dive, or at least down to 300 m.

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Toledo, G., and A. Langguth. "Maxillary teeth in sperm whales, Physeter macrocephalus (Cetacea: Physeteridae)." Journal of Morphological Sciences 32, no. 03 (2015): 212–15. http://dx.doi.org/10.4322/jms.082314.

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AbstractSperm whales, Physeter macrocephalus Linnaeus, 1758, have 18 to 28 pairs of well developed conical mandibular teeth, but maxillary teeth are vestigial and supposedly rare. The aim of this study is to report a new case of erupted maxillary teeth in P. macrocephalus, the first description for Brazil. On 29 October 2008 a female sperm whale was found stranded in Campina's Beach (06° 46' S, 34° 55' W), Paraíba state, northeastern Brazil. Inspection on the gums revealed three upper teeth on the right maxilla, corresponded to mandibular teeth 9 to 11 in a rostrocaudal sequence. The maxillary teeth were nearly straight, strongly worn in the tip and had no pulp cavity remaining. Most literature states that maxillary teeth are absent or rarely present, somewhat questionable, since other authors never failed to expose them by an incision in the gum. Data show that upper teeth have been overlooked, and its real frequency can only be determined by thorough dissections. This is important, since the study of maxillary teeth can provide information about evolution, functional morphology and age determination in sperm whales.

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Gonçalves, Leandra Regina, Mabel Augustowski, and Artur Andriolo. "Occurrence, distribution and behaviour of Bryde's whales (Cetacea: Mysticeti) off south-east Brazil." Journal of the Marine Biological Association of the United Kingdom 96, no. 4 (2015): 943–54. http://dx.doi.org/10.1017/s0025315415001812.

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Bryde's whales are among the lesser known balaenopterids found in Brazilian waters, as well as globally. At the beginning of this project, only occasional sightings of this species were identified off the coast of São Paulo State. In this paper, we present the results of our investigations into the occurrence and behaviour of Bryde's whales along the São Paulo coast, both inside and outside the Marine State Park of Laje de Santos, as a contribution to biological and behavioural knowledge of Bryde's whales under the conservation scope. Sighting surveys were conducted from January 2003 to July 2005 in coastal and oceanic areas. During the survey, 42 sightings were made, totalling 71 individuals, between the isobaths of 20 and 3000 m. Sightings and individual rates were higher in coastal areas during the summer season. Different kinds of behaviour were observed in coastal and oceanic areas. At the 1200 m isobath, notable social interactions were observed in which four adult individuals performed breaching – the first report of this behavioural pattern for Brazil. Results suggest that Bryde's whales possibly use coastal areas for feeding and may migrate to oceanic areas for breeding, thus providing important aspects that must be considered for the proper management of Marine Protected Areas and for oceanic areas, especially considering the intensive and continuous increase of oil and gas exploitation activities in those areas. Data reported here, therefore, constitute a significant contribution in Bryde's whale research and to cetacean conservation efforts in Brazil.

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Waller, G. N. H. "An annotated checklist of mesoplodont whale species (Cetacea, Ziphiidae) discovered after the nineteenth century." Archives of Natural History 44, no. 1 (2017): 31–42. http://dx.doi.org/10.3366/anh.2017.0412.

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Seven species of mesoplodont whales (genus Mesoplodon Gervais, 1850 ) named after the nineteenth century are based on valid descriptions. A checklist listing the original description and type material for each of these species is provided. Additional data given include type locality and illustrative sources, type material holding institution and type registration number. External morphology was recorded for all type specimens except Andrews' Beaked Whale (Mesoplodon bowdoini) and the Pygmy Beaked Whale (Mesoplodon peruvianus).

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Bisconti, Michelangelo, Luca Pellegrino, and Giorgio Carnevale. "Evolution of gigantism in right and bowhead whales (Cetacea: Mysticeti: Balaenidae)." Biological Journal of the Linnean Society 134, no. 2 (2021): 498–524. http://dx.doi.org/10.1093/biolinnean/blab086.

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Abstract The evolution of gigantic body size represents a key to understand the ecological role of baleen whales in oceanic ecosystems. Many efforts have been devoted to the formulation of equations relating different body parts to total body length and mass in living and fossil mysticetes, mainly focusing on balaenopterid and balaenopterid-like mysticetes. Right whales (family Balaenidae) have a unique head-to-body length ratio, suggesting that their body proportions cannot be predicted effectively using equations based primarily on non-balaenid mysticetes. A new morphometric dataset of living and fossil balaenids is provided herein, and new regression equations allow one to predict the body length and mass of extinct species based on the expected head-to-body length ratio of extant balaenids. The reconstructed values are mapped on a new phylogenetic analysis of the Balaenidae, inferring body size and mass at ancestral nodes. The variations of body size and mass in Balaenidae since the early Miocene are reconstructed, revealing that: (1) a reduction in total body length occurred in the early Pliocene; (2) the origin of the gigantic body size in the bowhead whale (Balaena mysticetus) is probably related to invasion of the Arctic Ocean in the last 3 Myr; and (3) the origin of the gigantic body size in the right whales (genus Eubalaena) occurred since the latest Miocene, probably concomitant with pulses of nutrients sustaining large zooplankton populations. We suggest that the evolution of gigantism in Balaenidae occurred independently in two lineages and, probably, in response to different palaeoenvironmental drivers.

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Tsai, Cheng-Hsiu, and R. Ewan Fordyce. "Ancestor–descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata." Biology Letters 11, no. 1 (2015): 20140875. http://dx.doi.org/10.1098/rsbl.2014.0875.

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Ancestor–descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, †Miocaperea pulchra , and its sole living relative, the enigmatic pygmy right whale Caperea marginata , the latter represented by both adult and juvenile specimens. †Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR—the first so far identified within baleen whales (Cetacea: Mysticeti). The †Miocaperea–Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.

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Bianucci, Giovanni, Christian de Muizon, Mario Urbina, and Olivier Lambert. "Extensive Diversity and Disparity of the Early Miocene Platanistoids (Cetacea, Odontoceti) in the Southeastern Pacific (Chilcatay Formation, Peru)." Life 10, no. 3 (2020): 27. http://dx.doi.org/10.3390/life10030027.

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Several aspects of the fascinating evolutionary history of toothed and baleen whales (Cetacea) are still to be clarified due to the fragmentation and discontinuity (in space and time) of the fossil record. Here we open a window on the past, describing a part of the extraordinary cetacean fossil assemblage deposited in a restricted interval of time (19–18 Ma) in the Chilcatay Formation (Peru). All the fossils here examined belong to the Platanistoidea clade as here redefined, a toothed whale group nowadays represented only by the Asian river dolphin Platanista gangetica. Two new genera and species, the hyper-longirostrine Ensidelphis riveroi and the squalodelphinid Furcacetus flexirostrum, are described together with new material referred to the squalodelphinid Notocetus vanbenedeni and fragmentary remains showing affinities with the platanistid Araeodelphis. Our cladistic analysis defines the new clade Platanidelphidi, sister-group to Allodelphinidae and including E. riveroi and the clade Squalodelphinidae + Platanistidae. The fossils here examined further confirm the high diversity and disparity of platanistoids during the early Miocene. Finally, morphofunctional considerations on the entire platanistoid assemblage of the Chilcatay Formation suggest a high trophic partitioning of this peculiar cetacean paleocommunity.

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Waller, G. N. H. "An annotated checklist of mesoplodont whale species (Cetacea, Ziphiidae) discovered during the nineteenth century." Archives of Natural History 42, no. 2 (2015): 226–35. http://dx.doi.org/10.3366/anh.2015.0307.

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Eight species of mesoplodont whales (genus Mesoplodon Gervais, 1850) named during the nineteenth century are based on valid descriptions. A checklist with the original description and type material for each of these species is provided. Additional data given may include type locality and illustrative sources, type material holding institution and type registration number(s). The only type specimen for which a record of external morphology was published relates to the 1803 stranding of Sowerby's beaked whale (Mesoplodon bidens).

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Ukishima, Yoshiyuki, Masahiko Kino, Hiroyuki Kubota, Shiro Wada, and Shoji Okada. "Identification of Whale Species by Thin-Layer Isoelectric Focusing of Sarcoplasmic Proteins1." Journal of AOAC INTERNATIONAL 74, no. 6 (1991): 943–50. http://dx.doi.org/10.1093/jaoac/74.6.943.

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Abstract Thin-layer isoelectric focusing was applied to the identification of whale (Cetacea) species by using water-soluble sarcoplasmic proteins of skeletal muscles. Twenty-eight samples consisting of 4 species (10 samples) of baleen whales (Mysticeti) and 8 species (18 samples) of toothed whales (Odontoceti) were analyzed. Each sample (approximately 1 g) was electrophoresed with Ampholine PAGplate, pH 3.5-9.5. The electrophoretic profiles were species-specific on the 4 toothed whale species that did not have a marked intra-species difference, and all 4 baleen whale species. However, the profiles were not specific on the 4 other dolphin species, even though they were discriminable from the other 4 toothed whale species. Numerical values of pls and relative peak heights were obtained by densitometric analysis of the isoelectro-focused protein bands. The bands were also species-specific for the 8 toothed whale species mentioned. The values may be applicable to species identification without the need for a standard sample, which may not be readily obtainable. Experiments on test samples of minke and sei whales showed that bloodletting with ice water made the densities of isoelectro-focused bands thinner, although species identification was still possible by using the Inside part of muscles. Heat treatment at below 60°C for 10 min caused little denaturation; at higher temperatures the protein bands were diminished in a temperature-dependent fashion. Therefore, the present isoelectric focusing analysis should be applicable to small samples of whale meat, excluding several species of dolphins.

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Lopes-Marques, Mónica, André M. Machado, Luís Q. Alves, et al. "Complete Inactivation of Sebum-Producing Genes Parallels the Loss of Sebaceous Glands in Cetacea." Molecular Biology and Evolution 36, no. 6 (2019): 1270–80. http://dx.doi.org/10.1093/molbev/msz068.

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AbstractGenomes are dynamic biological units, with processes of gene duplication and loss triggering evolutionary novelty. The mammalian skin provides a remarkable case study on the occurrence of adaptive morphological innovations. Skin sebaceous glands (SGs), for instance, emerged in the ancestor of mammals serving pivotal roles, such as lubrication, waterproofing, immunity, and thermoregulation, through the secretion of sebum, a complex mixture of various neutral lipids such as triacylglycerol, free fatty acids, wax esters, cholesterol, and squalene. Remarkably, SGs are absent in a few mammalian lineages, including the iconic Cetacea. We investigated the evolution of the key molecular components responsible for skin sebum production: Dgat2l6, Awat1, Awat2, Elovl3, Mogat3, and Fabp9. We show that all analyzed genes have been rendered nonfunctional in Cetacea species (toothed and baleen whales). Transcriptomic analysis, including a novel skin transcriptome from blue whale, supports gene inactivation. The conserved mutational pattern found in most analyzed genes, indicates that pseudogenization events took place prior to the diversification of modern Cetacea lineages. Genome and skin transcriptome analysis of the common hippopotamus highlighted the convergent loss of a subset of sebum-producing genes, notably Awat1 and Mogat3. Partial loss profiles were also detected in non-Cetacea aquatic mammals, such as the Florida manatee, and in terrestrial mammals displaying specialized skin phenotypes such as the African elephant, white rhinoceros and pig. Our findings reveal a unique landscape of “gene vestiges” in the Cetacea sebum-producing compartment, with limited gene loss observed in other mammalian lineages: suggestive of specific adaptations or specializations of skin lipids.

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Rottner, Regina. "Are “non-human sounds/music” lesser than human music? A comparison from a biological and musicological perspective." Sign Systems Studies 37, no. 3/4 (2009): 509–24. http://dx.doi.org/10.12697/sss.2009.37.3-4.07.

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The complexity and variation of sound emission by members of the animal kingdom, primarily produced by the orders Passeriformes (songbirds), Cetacea (whales), but also reported in species belonging to the Exopterygota (insects) and Carnivora (mammals), has attracted human attention since the Middle Ages, where birds’ calls were used in compositions of that time. However, the focus of this paper will be on sound productions of birds and whales, as recent scientific and musicological research concentrates on these two animals.

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Versiani, Leonardo Leão, and Cristiano Schetini Azevedo. "Surface activity of Humpback whales Megaptera novaeangliae (Cetacea, Mysticeti) on the northern coast of Bahia, Brazil." Revista Brasileira de Zoociências 21, no. 1 (2020): 1–12. http://dx.doi.org/10.34019/2596-3325.2020.v21.29788.

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Surface activities of humpback whale groups were studied during the reproductive seasons of 2008, 2009 and 2010 on the northern coast of Bahia State, Brazil, near the district of Praia do Forte. The level of surface activity exhibited by 342 groups of whales was evaluated according to the sea state (measured on the Beaufort scale) and cloud coverage. Five behaviours were recorded: breaching, head slapping, tail slapping, pectoral flipper slapping and tail breaching. Most of the sightings occurred with a sea state classified on the Beaufort scale as 2, and with a cloud coverage of 26 to 50%. The most recorded level of surface activity was pectoral flipper slapping. The results showed that humpback whale behaviours do not seem to be influenced by the sea state or by cloud coverage.

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Racicot, Rachel A., Robert W. Boessenecker, Simon A. F. Darroch, and Jonathan H. Geisler. "Evidence for convergent evolution of ultrasonic hearing in toothed whales (Cetacea: Odontoceti)." Biology Letters 15, no. 5 (2019): 20190083. http://dx.doi.org/10.1098/rsbl.2019.0083.

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Toothed whales (Cetacea: Odontoceti) are the most diverse group of modern cetaceans, originating during the Eocene/Oligocene transition approximately 38 Ma. All extant odontocetes echolocate; a single origin for this behaviour is supported by a unique facial source for ultrasonic vocalizations and a cochlea adapted for hearing the corresponding echoes. The craniofacial and inner ear morphology of Oligocene odontocetes support a rapid (less than 5 Myr) early evolution of echolocation. Although some cranial features in the stem odontocetes Simocetus and Olympicetus suggest an ability to generate ultrasonic sound, until now, the bony labyrinths of taxa of this grade have not been investigated. Here, we use µCT to examine a petrosal of a taxon with clear similarities to Olympicetus avitus . Measurements of the bony labyrinth, when added to an extensive dataset of cetartiodactyls, resulted in this specimen sharing a morphospace with stem whales, suggesting a transitional inner ear. This discovery implies that either the lineage leading to this Olympicetus -like taxon lost the ability to hear ultrasonic sound, or adaptations for ultrasonic hearing evolved twice, once in xenorophids and again on the stem of the odontocete crown group. We favour the latter interpretation as it matches a well-documented convergence of craniofacial morphology between xenorophids and extant odontocetes.

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Churchill, Morgan, Jonathan H. Geisler, Brian L. Beatty, and Anjali Goswami. "Evolution of cranial telescoping in echolocating whales (Cetacea: Odontoceti)." Evolution 72, no. 5 (2018): 1092–108. http://dx.doi.org/10.1111/evo.13480.

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Fitzgerald, Erich M. G. "A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales." Proceedings of the Royal Society B: Biological Sciences 273, no. 1604 (2006): 2955–63. http://dx.doi.org/10.1098/rspb.2006.3664.

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Extant baleen whales (Cetacea, Mysticeti) are all large filter-feeding marine mammals that lack teeth as adults, instead possessing baleen, and feed on small marine animals in bulk. The early evolution of these superlative mammals, and their unique feeding method, has hitherto remained enigmatic. Here, I report a new toothed mysticete from the Late Oligocene of Australia that is more archaic than any previously described. Unlike all other mysticetes, this new whale was small, had enormous eyes and lacked derived adaptations for bulk filter-feeding. Several morphological features suggest that this mysticete was a macrophagous predator, being convergent on some Mesozoic marine reptiles and the extant leopard seal ( Hydrurga leptonyx ). It thus refutes the notions that all stem mysticetes were filter-feeders, and that the origins and initial radiation of mysticetes was linked to the evolution of filter-feeding. Mysticetes evidently radiated into a variety of disparate forms and feeding ecologies before the evolution of baleen or filter-feeding. The phylogenetic context of the new whale indicates that basal mysticetes were macrophagous predators that did not employ filter-feeding or echolocation, and that the evolution of characters associated with bulk filter-feeding was gradual.

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Hazevoet, Cornelis J., and Frederick W. Wenzel. "Whales and dolphins (Mammalia, Cetacea) of the Cape Verde Islands, with special reference to the Humpback Whale Megaptera novaeangliae (Borowski, 1781)." Contributions to Zoology 69, no. 3 (2000): 197–211. http://dx.doi.org/10.1163/18759866-06903004.

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Observations of whales and dolphins in the Cape Verde Islands obtained in 1995 and 1996 are reported and data on the occurrence of 14 taxa are given, including four not previously reported from the region, viz. Bryde’s Whale Balaenoptera edeni, Killer Whale Orcinus orca,Rough-toothed Dolphin Steno bredanensis, and Striped Dolphin Stenella coeruleoalba. An earlier report of Fin Whale B. physalus is reviewed and re-identified as B. cf. borealis. Status and occurrence of the Humpback Whale Megaptera novaeangliae are discussed at some length. Unpublished observations from other observers are also included and a short account on the history of whaling in the islands is given. A list of all cetacean taxa reliably recorded in the Cape Verde region is presented and unsubstantiated reports are briefly discussed.

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Robineau, Daniel, and Vivian de Buffrénil. "Nouvelles données sur la masse du squelette chez les grands cétacés (Mammalia, Cetacea)." Canadian Journal of Zoology 71, no. 4 (1993): 828–34. http://dx.doi.org/10.1139/z93-108.

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The mass of dry and fat-free skeletons was measured in a small sample representing five species of large cetaceans: two balaenids, two balaenopterids, and one physeterid (the sperm whale). Expressed as a percentage of total body mass, skeletal mass in these animals varies from 3.5 to 5%. Such values are very close to those established previously for small to medium size toothed whales. This means that the dynamics of mass growth of the skeleton, as compared with that of the body as a whole, does not follow a positive allometry in cetaceans. Such a growth pattern differs markedly from the tendencies described in terrestrial mammals. Conversely, it is similar to that described in bony fishes. The distribution of loads within the skeletons reflects rather different functional patterns among the taxa examined here. The possible adaptive significance of these differences is discussed in reference to the locomotion of large cetaceans.

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Juri, Eduardo, Meica Valdivia, Paulo Cesar Simoes-Lopes, and Alfredo Le Bas. "A note on minke whales (Cetacea: Balaenopteridae) in Uruguay: strandings review." J. Cetacean Res. Manage. 21, no. 1 (2020): 135–40. http://dx.doi.org/10.47536/jcrm.v21i1.203.

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The minke whale is the smallest of the living rorquals and is widely distributed in the tropical, temperate and polar waters of both hemispheres. In the western Southwest Atlantic Ocean there are two currently recognised species, the dwarf form of the common minke whale, Balaenoptera acutorostrata unnamed subsp. and the Antarctic minke whale B. bonaerensis. All stranding records and collected specimens of minke whale on the coast of Uruguay were reviewed and analysed. Between 1962 and 2018, 33 records were gathered in a non-systematic way, 22 specimens of B. acutorostrata and 11 of B. bonaerensis. It was found that most animals were discovered alive or recently dead and assigned as neonates/young calves. This supports the hypothesis that Uruguayan coasts are part of an important region for reproduction and breeding for the species.

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Geisler, Jonathan H., and Zhexi Luo. "The petrosal and inner ear of Herpetocetus sp. (Mammalia: Cetacea) and their implications for the phylogeny and hearing of archaic mysticetes." Journal of Paleontology 70, no. 6 (1996): 1045–66. http://dx.doi.org/10.1017/s0022336000038749.

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This paper describes the petrosal (periotic) and the inner ear of Herpetocetus sp., an archaic mysticete whale (Mysticeti, Mammalia) from the Yorktown Formation (Pliocene) of North Carolina, USA. Parsimony analysis of 28 petrosal characters of Herpetocetus sp. and 11 other cetacean taxa supports the monophyly of mysticetes and the division of odontocetes and mysticetes. The in-group taxa of this analysis are: Herpetocetus, Parietobalaena, Pelocetus, Balaenidae, Eschrichtius, and Balaenopteridae. Odontocetes and the archaeocete Zygorhiza were used as successive outgroups to root phylogenetic trees and to establish character polarities. Among the modern mysticetes, the Balaenopteridae (rorquals) and the Eschrichtiidae (gray whales) are more closely related to each other than either is to the Balaenidae (bowhead and right whales). Several Miocene “cetotheriid” mysticetes and balaenids share some resemblance in the petrosal, suggesting their affinities. Quantitative information of the inner ear of Herpetocetus sp. was obtained by serial sectioning and computer graphic reconstruction. Herpetocetus sp. is much less developed than odontocetes in the cochlear structures that are crucial for high frequency hearing. Some cochlear structures in this fossil mysticete resemble more closely the non-echolocating modern mysticetes than early fossil toothed whales, indicating a possible specialization in low frequency hearing. This suggests that the archaic mysticetes of the Miocene and Pliocene did not have high frequency hearing necessary for echolocation. Herpetocetus sp. is similar to modern mysticetes but different from odontocetes in the spherical shape of the vestibule.

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Mourlam, Mickaël J., and Maeva J. Orliac. "Early evolution of the ossicular chain in Cetacea: into the middle ear gears of a semi-aquatic protocetid whale." Proceedings of the Royal Society B: Biological Sciences 286, no. 1912 (2019): 20191417. http://dx.doi.org/10.1098/rspb.2019.1417.

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Modifications of the morphology and acoustic properties of the ossicular chain are among the major changes that accompanied the adaptation of Cetacea to the aquatic environment. Thus, data on the middle ear ossicles of early whales are crucial clues to understand the first steps of the emblematic terrestrial/aquatic transition that occurred in that group. Yet, the delicate nature and very small size of these bones make their preservation in the fossil record extremely rare. Due to the scarcity of available data, major questions remain concerning the sound transmission pathways in early non-fully aquatic whales. Virtual reconstruction of a partially complete ossicular chain of an Eocene protocetid whale documents for the first time the three ossicles of a semi-aquatic archaeocete. Contrary to previous hypotheses, these ossicles present different evolutionary patterns, showing that the ossicular chain does not act as a single morphological module. Functional analyses of the different middle ear units highlight a mosaic pattern of terrestrial and aquatic signatures. This integrative anatomical and functional study brings strong evidence that protocetids were adapted to their dual acoustic environment with efficient hearing in both air and water.

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Alves, Luís Q., Juliana Alves, Rodrigo Ribeiro, Raquel Ruivo, and Filipe Castro. "The dopamine receptor D5 gene shows signs of independent erosion in toothed and baleen whales." PeerJ 7 (October 11, 2019): e7758. http://dx.doi.org/10.7717/peerj.7758.

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To compare gene loci considering a phylogenetic framework is a promising approach to uncover the genetic basis of human diseases. Imbalance of dopaminergic systems is suspected to underlie some emerging neurological disorders. The physiological functions of dopamine are transduced via G-protein-coupled receptors, including DRD5 which displays a relatively higher affinity toward dopamine. Importantly, DRD5 knockout mice are hypertense, a condition emerging from an increase in sympathetic tone. We investigated the evolution of DRD5, a high affinity receptor for dopamine, in mammals. Surprisingly, among 124 investigated mammalian genomes, we found that Cetacea lineages (Mysticeti and Odontoceti) have independently lost this gene, as well as the burrowing Chrysochloris asiatica (Cape golden mole). We suggest that DRD5 inactivation parallels hypoxia-induced adaptations, such as peripheral vasoconstriction required for deep-diving in Cetacea, in accordance with the convergent evolution of vasoconstrictor genes in hypoxia-exposed animals. Our findings indicate that Cetacea are natural knockouts for DRD5 and might offer valuable insights into the mechanisms of some forms of vasoconstriction responses and hypertension in humans.

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Gingerich, Philip D., and Mark D. Uhen. "Likelihood Estimation of the Time of Origin of Whales (Cetacea)." Paleontological Society Special Publications 8 (1996): 146. http://dx.doi.org/10.1017/s2475262200001489.

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Weitkowitz, Walter. "Sightings of whales and dolphins in the Middle East (Cetacea)." Zoology in the Middle East 6, no. 1 (1992): 5–12. http://dx.doi.org/10.1080/09397140.1992.10637606.

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DALEBOUT, M. L., A. VAN HELDEN, K. VAN WAEREBEEK, and C. S. BAKER. "Molecular genetic identification of southern hemisphere beaked whales (Cetacea: Ziphiidae)." Molecular Ecology 7, no. 6 (1998): 687–94. http://dx.doi.org/10.1046/j.1365-294x.1998.00380.x.

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Lunardi, Diana G., Márcia H. Engel, and Regina H. F. Macedo. "Behavior of humpback whales, Megaptera novaeangliae (Cetacea: Balaenopteridae): comparisons between two coastal areas of Brazil." Revista Brasileira de Zoologia 25, no. 2 (2008): 159–64. http://dx.doi.org/10.1590/s0101-81752008000200001.

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Behavior of humpback whales was observed during the reproductive period off the northern coast of the state of Bahia (NB, n = 378 groups) and at the Abrolhos Bank (AB, n = 919) to compare patterns and group composition between the two locations. Alone individuals and dyads were most often encountered in both areas, although mother-calf pairs were more common in AB. While these two regions comprise distinct concentrations of humpback whales, with intrinsic environmental differences, behavior patterns were quite similar. The only behavioral differences found where for "tail up" and "resting". The patterns found here may reflect differences in the protection status of the areas or intrinsic environmental differences.

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Blanco, C., and J. A. Raga. "Cephalopod prey of two Ziphius cavirostris (Cetacea) stranded on the western Mediterranean coast." Journal of the Marine Biological Association of the United Kingdom 80, no. 2 (2000): 381–82. http://dx.doi.org/10.1017/s0025315499002064.

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The stomach contents of two Cuvier's beaked whales (Ziphius cavirostris), male and female, stranded on the western Mediterranean coast were analysed. Food consisted exclusively of hard cephalopod remains. The character of this teuthophagous diet agrees with the offshore and deep diving behaviour of Z. cavirostris.

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Olsen, M. A., A. S. Blix, THA Utsi, W. Sørmo, and S. D. Mathiesen. "Chitinolytic bacteria in the minke whale forestomach." Canadian Journal of Microbiology 46, no. 1 (1999): 85–94. http://dx.doi.org/10.1139/w99-112.

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Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the β-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular forestomach. Bacteria in the forestomach fluid of six krill-eating minke whales were enumerated and isolated using an anaerobic habitat-simulating culture medium. Median viable population densities ranged between 6.0 × 106and 9.9 × 109bacterial cells per mL forestomach fluid. Bacterial isolates (n = 44) cultured from the forestomach fluid of one minke whale mainly resembled strains of Eubacterium (25%),Streptococcus (18%), Clostridium (14%), and Bacteroides (11%). As much as 12% of the bacterial isolates were chitinolytic, while β-N-acetylglucosaminidase activity was demonstrated in 54% of the isolates, and utilisation of N-acetyl-D-glucosamine was observed in 73%. The chitinolytic isolates resembled strains of Bacteroides, Bacteroidaceae, Clostridium, and Streptococcus. Scanning and transmission electron microscopy of partly digested krill from the minke whale forestomach revealed bacteria close to and inside the chitinous exoskeleton. The bacterial chitinase may act on the chitinous crustacean exoskeletons, thereby allowing other bacteria access to the nutritious soft inner tissues of the prey, and thus initiating its degradation and fermentation.Key words: chitinase, β-N-acetylglucosaminidase, cetacea, symbiotic microbial digestion.

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Bajpai, S., J. G. M. Thewissen, and R. W. Conley. "Cranial anatomy of middle EoceneRemingtonocetus(Cetacea, Mammalia) from Kutch, India." Journal of Paleontology 85, no. 4 (2011): 703–18. http://dx.doi.org/10.1666/10-128.1.

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The family Remingtonocetidae is a basal family of Eocene cetaceans only known from near shore marine environments of India and Pakistan. We describe a new skull forRemingtonocetus harudiensiswhich elucidates the anatomy and functional morphology of the head and provides new details on cranial cavity and nasopharyngeal region. We suggest thatRemingtonocetuswas an ambush predator that hunted from a perch on the ocean floor, and that hearing was its most important sense. We speculate that the greatly elongated rostrum is an adaptation for water retention because these are some of the earliest whales living in seawater.

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Shipps, B. K., Carlos Mauricio Peredo, and Nicholas D. Pyenson. "Borealodon osedax , a new stem mysticete (Mammalia, Cetacea) from the Oligocene of Washington State and its implications for fossil whale-fall communities." Royal Society Open Science 6, no. 7 (2019): 182168. http://dx.doi.org/10.1098/rsos.182168.

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Baleen whales (mysticetes) lack teeth as adults and instead filter feed using keratinous baleen plates. They do not echolocate with ultrasonic frequencies like toothed whales but are instead known for infrasonic acoustics. Both baleen and infrasonic hearing are separately considered key innovations linked to their gigantism, evolutionary success and ecological diversity. The earliest mysticetes had teeth, and the phylogenetic position of many so-called toothed mysticetes remains debated, including those belonging to the nominal taxonomic groups Llanocetidae, Mammalodontidae and Aetiocetidae. Here, we report a new stem mysticete, Borealodon osedax gen. et sp. nov., from the Oligocene of Washington State, USA. Borealodon preserves multi-cusped teeth with apical wear; microCT scans of the inner ear indicate that the minimum frequency hearing limit of Borealodon was similar to mammalodontids. Borealodon is not recovered within a monophyletic Mammalodontidae nor a monophyletic Aetiocetidae; instead, it represents an unnamed lineage of stem Mysticeti, adding to the diversity of stem mysticetes, especially across the Rupelian–Chattian boundary. Furthermore, the presence of a putative chemosynthetic bivalve along with Osedax , a bone-boring annelid, found in association with the type specimen of Borealodon , offer more insights into the evolution of deep-sea whale-fall communities.

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Fitzgerald, Erich M. G. "Archaeocete-like jaws in a baleen whale." Biology Letters 8, no. 1 (2011): 94–96. http://dx.doi.org/10.1098/rsbl.2011.0690.

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The titanic baleen whales (Cetacea, Mysticeti) have a bizarre skull morphology, including an elastic mandibular symphysis, which permits dynamic oral cavity expansion during bulk feeding. How this key innovation evolved from the sutured symphysis of archaeocetes has remained unclear. Now, mandibles of the Oligocene toothed mysticete Janjucetus hunderi show that basal mysticetes had an archaeocete-like sutured symphysis. This archaic morphology was paired with a wide rostrum typical of later-diverging baleen whales. This demonstrates that increased oral capacity via rostral widening preceded the evolution of mandibular innovations for filter feeding. Thus, the initial evolution of the mysticetes' unique cranial form and huge mouths was perhaps not linked to filtering plankton, but to enhancing suction feeding on individual prey.

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Hartenberger, Jean-Louis. "The emergence of whales. Evolutionary patterns in the origin of Cetacea." Geobios 32, no. 2 (1999): 222. http://dx.doi.org/10.1016/s0016-6995(99)80034-5.

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Baker, Alan N., and Anton L. van Helden. "New records of beaked whales, GenusMesoplodon,from New Zealand (Cetacea: Ziphiidae)." Journal of the Royal Society of New Zealand 29, no. 3 (1999): 235–44. http://dx.doi.org/10.1080/03014223.1999.9517594.

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Rendell, Luke, Mauricio Cantor, Shane Gero, Hal Whitehead, and Janet Mann. "Causes and consequences of female centrality in cetacean societies." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1780 (2019): 20180066. http://dx.doi.org/10.1098/rstb.2018.0066.

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Cetaceans are fully aquatic predatory mammals that have successfully colonized virtually all marine habitats. Their adaptation to these habitats, so radically different from those of their terrestrial ancestors, can give us comparative insights into the evolution of female roles and kinship in mammalian societies. We provide a review of the diversity of such roles across the Cetacea, which are unified by some key and apparently invariable life-history features. Mothers are uniparous, while paternal care is completely absent as far as we currently know. Maternal input is extensive, lasting months to many years. Hence, female reproductive rates are low, every cetacean calf is a significant investment, and offspring care is central to female fitness. Here strategies diverge, especially between toothed and baleen whales, in terms of mother–calf association and related social structures, which range from ephemeral grouping patterns to stable, multi-level, societies in which social groups are strongly organized around female kinship. Some species exhibit social and/or spatial philopatry in both sexes, a rare phenomenon in vertebrates. Communal care can be vital, especially among deep-diving species, and can be supported by female kinship. Female-based sociality, in its diverse forms, is therefore a prevailing feature of cetacean societies. Beyond the key role in offspring survival, it provides the substrate for significant vertical and horizontal cultural transmission, as well as the only definitive non-human examples of menopause. This article is part of the theme issue ‘The evolution of female-biased kinship in humans and other mammals’.

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Leslie, Matthew S., Carlos Mauricio Peredo, and Nicholas D. Pyenson. "Norrisanima miocaena, a new generic name and redescription of a stem balaenopteroid mysticete (Mammalia, Cetacea) from the Miocene of California." PeerJ 7 (October 8, 2019): e7629. http://dx.doi.org/10.7717/peerj.7629.

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Rorqual whales are among the most species rich group of baleen whales (or mysticetes) alive today, yet the monophyly of the traditional grouping (i.e., Balaenopteridae) remains unclear. Additionally, many fossil mysticetes putatively assigned to either Balaenopteridae or Balaenopteroidea may actually belong to stem lineages, although many of these fossil taxa suffer from inadequate descriptions of fragmentary skeletal material. Here we provide a redescription of the holotype of Megaptera miocaena, a fossil balaenopteroid from the Monterey Formation of California, which consists of a partial cranium, a fragment of the rostrum, a single vertebra, and both tympanoperiotics. Kellogg (1922) assigned the type specimen to the genus Megaptera Gray (1846), on the basis of its broad similarities to distinctive traits in the cranium of extant humpback whales (Megaptera novaeangliae (Borowski, 1781)). Subsequent phylogenetic analyses have found these two species as sister taxa in morphological datasets alone; the most recent systematic analyses using both molecular and morphological data sets place Megaptera miocaena as a stem balaenopteroid unrelated to humpback whales. Here, we redescribe the type specimen of Megaptera miocaena in the context of other fossil balaenopteroids discovered nearly a century since Kellogg’s original description and provide a morphological basis for discriminating it from Megaptera novaeangliae. We also provide a new generic name and recombine the taxon as Norrisanima miocaena, gen. nov., to reflect its phylogenetic position outside of crown Balaenopteroidea, unrelated to extant Megaptera. Lastly, we refine the stratigraphic age of Norrisanima miocaena, based on associated microfossils to a Tortonian age (7.6–7.3 Ma), which carries implications for understanding the origin of key features associated with feeding and body size evolution in this group of whales.

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Magalhães, FA, CH Tosi, RG Garri, S. Chellappa, and FL Silva. "Cetacean diversity on the Parnaiba Delta, Maranhão state, northeastern Brazil." Brazilian Journal of Biology 68, no. 3 (2008): 545–51. http://dx.doi.org/10.1590/s1519-69842008000300012.

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The increase in the research of cetacean surveys on the Brazilian coast has brought new data on the distribution of species never reported before. The present work reviews the current knowledge on cetaceans species and extends this knowledge with an analysis of cetaceans stranded in the Parnaiba Delta, on the coast of Maranhão State, Brazil. The studies on cetacean diversity on the coast of the Parnaíba Delta were made from August 2004 to August 2006. Fourteen strandings were reported, representing six distinct species, such as the estuarine dolphin (Sotalia guianensis), humpback whale (Megaptera novaeangliae), Bryde's whales (Balaenoptera edeni), dwarf minke whale (Balaenoptera acutorostrata), pigmy killer whale (Feresa attenuata), sperm whale (Physeter macrocephalus) and two specimens which have not yet been identified. The significant degree of cetacean diversity in the region shows that the Parnaíba Delta is, possibly, of an important area for cetacean studies in Brasil.

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Buchholtz, Emily A. "Vertebral osteology and swimming style in living and fossil whales (Order: Cetacea)." Journal of Zoology 253, no. 2 (2001): 175–90. http://dx.doi.org/10.1017/s0952836901000164.

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Canella, E. G., and D. J. Kitchener. "Differences in mercury levels in female sperm whales, Physeter macrocephalus (Cetacea: Odontoceti)." Australian Mammalogy 15, no. 1 (1992): 121. http://dx.doi.org/10.1071/am92016.

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Smith, Tim D. "Encountering whales: How encounter rates became the basis for managing whaling." NAMMCO Scientific Publications 7 (September 1, 2009): 221. http://dx.doi.org/10.7557/3.2715.

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Declining rates of encountering whales, including both sighting and catching, were noted by whalers throughout the 19th century, and these declines became the first indication that whaling was adversely affecting whale abundance. The interpretation of declines in both sighting and catch rates proved to be a difficult scientific task. Satisfactory quantitative methods of interpreting changes in whale encounter rates were not developed until the second half of the 20th century. Rates of encountering whales played a key role in the International Whaling Commission (IWC) Scientific Committee from its beginning in the early 1950s, as well as in the US in implementing its Marine Mammal Protection Act beginning in the early 1970s. The development of methods of collecting and interpreting sighting and catch data was intimately interwoven with the development of themanagement of whaling and cetacean by-catches in fisheries throughout the world, but especially within the context of the Scientific Committees of the IWC and the North Atlantic Marine Mammal Commission (NAMMCO). Although overfishing of whales was initially identified through the use of sighting rate data, catch rate data provided the IWC’s Committee its first firm footing for management advice. However, it was sighting rate data that ultimately became the basis for the scientific advice on whaling and for management advice in other settings. This led to the development of large scale cetacean sighting programmes, such as the IWC’s International Decade of Cetacean Researchsurveys in Antarctic aboard Japanese ships, the North Atlantic Sighting Surveys (NASS) aboard Norwegian, Icelandic, Spanish, Greenlandic and Faroese vessels and aircraft (coordinated by NAMMCO through its Scientific Committee from 1995), and surveys under the US’s Marine Mammal Protection Act and the European Union’s Small Cetacean Abundance in the North Sea (SCANS) programme. Fishery independent cetacean sighting surveys have proven to be both central and essential to understanding and regulating of human impacts on cetaceans.

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Viddi, Francisco A., Rodrigo Hucke-Gaete, Juan P. Torres-Florez, and Sandra Ribeiro. "Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile." ICES Journal of Marine Science 67, no. 5 (2010): 959–70. http://dx.doi.org/10.1093/icesjms/fsp288.

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Abstract Viddi, F. A., Hucke-Gaete, R., Torres-Florez, J. P., and Ribeiro, S. 2010. Spatial and seasonal variability in cetacean distribution in the fjords of northern Patagonia, Chile. – ICES Journal of Marine Science, 67: 959–970. Compared with other Chilean coastal areas, little is known about the diversity and distribution of cetaceans in northern Patagonian fjords. Between December 2000 and November 2001, surveys on platforms of opportunity were undertaken in southern Chile to evaluate species richness and the spatial and seasonal distribution of cetaceans. Nine species were recorded, blue, humpback, and minke whales, Peale's dolphin, Chilean dolphin, killer whale, false killer whale, bottlenose dolphin, and Cuvier's beaked whale. The pattern of cetacean distribution displayed significant seasonal differences, with most baleen whales (mysticetes) observed during late summer and autumn, and toothed cetaceans (odontocetes) mostly during spring. Generalized additive models, used to assess the spatial distribution of cetaceans, showed that mysticetes were distributed disproportionately along a north–south gradient, in open gulfs with oceanic influence, and close to shore. In contrast, odontocetes were observed mainly within narrow channels, areas with complex coastal morphology, peaking at different water depths. These findings, although from a single year of data, increase our understanding of habitat determinants of cetacean distribution in southern Chile. The results have the potential to be applied to coastal conservation and management in the region.

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Lucero, Sergio O., María Constanza Gariboldi, Valeria Bauni, et al. "Stranded humpback whale (Megaptera novaeangliae) (Cetacea: Balaenopteridae) in Paraná River Delta, Buenos Aires Province, Argentina. Comments on the occurrence of marine mammals in the La Plata River Basin." Papéis Avulsos de Zoologia 58 (February 20, 2018): 1. http://dx.doi.org/10.11606/1807-0205/2018.58.01.

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The humpback whale (Megaptera novaeangliae) is distributed among most oceans and seas of the globe (except Mediterranean Sea). These whales migrate from feeding regions in the Antarctic waters to breeding areas in tropical and subtropical seas. Here we report the stranding of a female young humpback whale, which was founded dead in the vicinity of the Talavera Island, in the Paraná River Delta, Buenos Aires Province, Argentina. From the analysis of mitochondrial cytochrome c oxidase subunit I gene sequences, two novel haplotypes were found, totalizing four haplotypes described for the species. In the La Plata River Basin this species was found only twice at the end of the XIX century. Thus, the new finding constitutes an important addition to the list of cetaceans that occurs in Uruguay, Paraná and La Plata Rivers.

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Oelschläger, Helmut A. "Comparative morphology and evolution of the otic region in toothed whales (Cetacea, Mammalia)." American Journal of Anatomy 177, no. 3 (1986): 353–68. http://dx.doi.org/10.1002/aja.1001770306.

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Brown Gladden, J. G., M. M. Ferguson, and J. W. Clayton. "Matriarchal genetic population structure of North American beluga whales Delphinapterus leucas (Cetacea: Monodontidae)." Molecular Ecology 6, no. 11 (1997): 1033–46. http://dx.doi.org/10.1046/j.1365-294x.1997.00275.x.

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Journal articles on the topic 'Whales Whales Whales Cetacea Cetacea Cetacea'

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