1
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Sanks J, Racicot R. Predicting ecology and hearing sensitivities in Parapontoporia-An extinct long-snouted dolphin. Anat Rec (Hoboken) 2024. [PMID: 39010732 DOI: 10.1002/ar.25538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/14/2024] [Accepted: 06/27/2024] [Indexed: 07/17/2024]
Abstract
Analyses of the cetacean (whale and dolphin) inner ear provide glimpses into the ecology and evolution of extinct and extant groups. The paleoecology of the long-snouted odontocete (toothed whale) group, Parapontoporia, is primarily marine with its depositional context also suggesting freshwater tolerance. As an extinct relative of the exclusively riverine Lipotes vexillifer, Parapontoporia provides insight into a transition from marine to freshwater environments. High-resolution X-ray CT scans (~3 microns or less) of three individual specimens from two species, P. sternbergi and P. pacifica, were acquired. Digital endocasts of the inner ear labyrinths were extracted non-destructively. Nine measurements of the inner ear were compared with an existing dataset covering 125 terrestrial and aquatic artiodactyls. These measurements were then subjected to a principal component analysis to interpret hearing sensitivities among other artiodactyls. Based on our analyses, Parapontoporia was likely to have been able to hear within narrow-band high frequency (NBHF) ranges. This finding indicates another convergence of NBHF-style hearing, or, more intriguingly, suggests that it may be an ancestral characteristic present among the longirostrine dolphins that dominated in the Miocene prior to the evolution of more modern lineages.
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Affiliation(s)
- Joyce Sanks
- Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Rachel Racicot
- Messel Research and Mammalogy Department, Senckenberg Forschungsinstitut und Naturkundemuseum (Senckenberg Research Institute and Natural History Museum), Frankfurt am Main, Germany
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2
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Zhao L, Cheng J, Zeng W, Yang B, Zhang G, Li D, Zhang H, Buesching CD, Liu D. Giant panda (Ailuropoda melanoleuca) neonates use broadband calls to communicate with their mothers. Integr Zool 2024; 19:277-287. [PMID: 37231635 DOI: 10.1111/1749-4877.12722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Infant call structure should have evolved to elicit maximum maternal attention and investment. Neonates of giant pandas produce three types of vocalizations reported to be vitally important in the context of mother-infant communications. However, how cubs, 0-15 days old, communicate with their mothers to elicit maternal care remains unknown. We analyzed 12 different call parameters of 3475 squawks, 1355 squalls, and 491 croaks from 11 captive giant panda (Ailuropoda melanoleuca) neonates from age 0 to 15 days. In playback experiments, we also tested whether mothers could detect ultrasound. Our results show that neonates use broadband calls with ultrasonic frequencies up to 65 kHz to convey information about their physiological needs and to attract maternal care. In playback experiments, we tested if mothers reacted differently to broadband calls (BBC) than to artificially altered calls that included only frequencies <20 kHz (AUDC) or calls that included only frequencies >20 kHz (USC). Playback confirmed that, although adult females responded significantly less often to USC, BBC than to or AUDC, they could detect USC, BBC and generally made appropriate behavioral responses, indicating a potential benefit for neonates to utilize ultrasonic and broadband frequencies. Our findings provide a new insight into mother-infant communication in giant pandas and will be helpful for reducing the mortality of cubs, younger than 1 month old, in captivity.
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Affiliation(s)
- Lin Zhao
- Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Jianbin Cheng
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Wen Zeng
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Bo Yang
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Guiquan Zhang
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Desheng Li
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Hemin Zhang
- Key Laboratory of State Forestry and Grassland Administration on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Center for the Giant Panda, Dujiangyan, Sichuan, 611830, China
| | - Christina D Buesching
- Department of Biology, Irving K. Barber Faculty of Science, University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
| | - Dingzhen Liu
- Ministry of Education, Key Laboratory of Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
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3
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Coombs EJ, Knapp A, Park T, Bennion RF, McCurry MR, Lanzetti A, Boessenecker RW, McGowen MR. Drivers of morphological evolution in the toothed whale jaw. Curr Biol 2024; 34:273-285.e3. [PMID: 38118449 DOI: 10.1016/j.cub.2023.11.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 12/22/2023]
Abstract
Toothed whales (odontocetes) emit high-frequency underwater sounds (echolocate)-an extreme and unique innovation allowing them to sense their prey and environment. Their highly specialized mandible (lower jaw) allows high-frequency sounds to be transmitted back to the inner ear. Echolocation is evident in the earliest toothed whales, but little research has focused on the evolution of mandibular form regarding this unique adaptation. Here, we use a high-density, three-dimensional geometric morphometric analysis of 100 living and extinct cetacean species spanning their ∼50-million-year evolutionary history. Our analyses demonstrate that most shape variation is found in the relative length of the jaw and the mandibular symphysis. The greatest morphological diversity was obtained during two periods of rapid evolution: the initial evolution of archaeocetes (stem whales) in the early to mid-Eocene as they adapted to an aquatic lifestyle, representing one of the most extreme adaptive transitions known, and later on in the mid-Oligocene odontocetes as they became increasingly specialized for a range of diets facilitated by increasingly refined echolocation. Low disparity in the posterior mandible suggests the shape of the acoustic window, which receives sound, has remained conservative since the advent of directional hearing in the aquatic archaeocetes, even as the earliest odontocetes began to receive sounds from echolocation. Diet, echolocation, feeding method, and dentition type strongly influence mandible shape. Unlike in the toothed whale cranium, we found no significant asymmetry in the mandible. We suggest that a combination of refined echolocation and associated dietary specializations have driven morphology and disparity in the toothed whale mandible.
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Affiliation(s)
- Ellen J Coombs
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, 10th St & Constitution Ave NW, Washington, DC 20560, USA; Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
| | - Andrew Knapp
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK; University College London, Gower Street, London WC1E 6BT, UK
| | - Travis Park
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK; School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Rebecca F Bennion
- Evolution & Diversity Dynamics Lab, Department of Geology, University of Liege, 4000 Liege, Belgium; O.D. Earth and History of Life, Royal Belgian Institute of Natural Sciences, 1000 Brussels, Belgium
| | - Matthew R McCurry
- Australian Museum Research Institute, 1 William Street, Sydney, NSW 2010, Australia; Earth & Sustainability Science Research Centre, School of Biological, Earth and Environmental Sciences (BEES), University of New South Wales, Kensington, NSW 2052, Australia; Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
| | - Agnese Lanzetti
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK; School of Geography, Earth, and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Robert W Boessenecker
- University of California Museum of Paleontology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael R McGowen
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, 10th St & Constitution Ave NW, Washington, DC 20560, USA
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4
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Ecomorphology of toothed whales (Cetacea, Odontoceti) as revealed by 3D skull geometry. J MAMM EVOL 2023. [DOI: 10.1007/s10914-022-09642-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AbstractExtant odontocetes (toothed whales) exhibit differences in body size and brain mass, biosonar mode, feeding strategies, and diving and habitat adaptations. Strong selective pressures associated with these factors have likely contributed to the morphological diversification of their skull. Here, we used 3D landmark geometric morphometric data from the skulls of 60 out of ~ 72 extant odontocete species and a well-supported phylogenetic tree to test whether size and shape variation are associated with ecological adaptations at an interspecific scale. Odontocete skull morphology exhibited a significant phylogenetic signal, with skull size showing stronger signal than shape. After accounting for phylogeny, significant associations were detected between skull size and biosonar mode, body length, brain and body mass, maximum and minimum prey size, and maximum peak frequency. Brain mass was also strongly correlated with skull shape together with surface temperature and average and minimum prey size. When asymmetric and symmetric components of shape were analysed separately, a significant correlation was detected between sea surface temperature and both symmetric and asymmetric components of skull shape, and between diving ecology and the asymmetric component. Skull shape variation of odontocetes was strongly influenced by evolutionary allometry but most of the associations with ecological variables were not supported after phylogenetic correction. This suggests that ecomorphological feeding adaptations vary more between, rather than within, odontocete families, and functional anatomical patterns across odontocete clades are canalised by size constraints.
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5
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Lactobacillus for ribosome peptide editing cancer. Clin Transl Oncol 2023; 25:1522-1544. [PMID: 36694080 PMCID: PMC9873400 DOI: 10.1007/s12094-022-03066-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/24/2022] [Indexed: 01/25/2023]
Abstract
This study reviews newly discovered insect peptide point mutations as new possible cancer research targets. To interpret newly discovered peptide point mutations in insects as new possible cancer research targets, we focused on the numerous peptide changes found in the 'CSP' family on the sex pheromone gland of the female silkworm moth Bombyx mori. We predict that the Bombyx peptide modifications will have a significant effect on cancer CUP (cancers of unknown primary) therapy and that bacterial peptide editing techniques, specifically Lactobacillus combined to CRISPR, will be used to regulate ribosomes and treat cancer in humans.
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6
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The tempo of cetacean cranial evolution. Curr Biol 2022; 32:2233-2247.e4. [DOI: 10.1016/j.cub.2022.04.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/28/2022] [Accepted: 04/21/2022] [Indexed: 01/05/2023]
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7
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Liu Z, Chen P, Xu DM, Qi FY, Guo YT, Liu Q, Bai J, Zhou X, Shi P. Molecular convergence and transgenic evidence suggest a single origin of laryngeal echolocation in bats. iScience 2022; 25:104114. [PMID: 35391832 PMCID: PMC8980745 DOI: 10.1016/j.isci.2022.104114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 03/07/2022] [Accepted: 03/15/2022] [Indexed: 10/28/2022] Open
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8
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Racicot R. Evolution of whale sensory ecology: Frontiers in nondestructive anatomical investigations. Anat Rec (Hoboken) 2021; 305:736-752. [PMID: 34546007 DOI: 10.1002/ar.24761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 06/09/2021] [Accepted: 07/14/2021] [Indexed: 12/18/2022]
Abstract
Studies surrounding the evolution of sensory system anatomy in cetaceans over the last ~100 years have shed light on aspects of the early evolution of hearing sensitivities, the small relative size of the organ of balance (semicircular canals and vestibule), brain (endocast) shape and relative volume changes, and ontogenetic development of sensory-related structures. Here, I review advances in our knowledge of sensory system anatomy as informed by the use of nondestructive imaging techniques, with a focus on applied methods in computed tomography (CT and μCT), and identify the key questions that remain to be addressed. Of these, the most important are: Is lower frequency hearing sensitivity the ancestral condition for whales? Did echolocation evolve more than once in odontocetes; and if so, when and why? How has the structure of the cetacean brain changed, through the evolution of whales, and does this correspond to changes in hearing sensitivities? Finally, what are the general pathways of ontogenetic development of sensory systems in odontocetes and mysticetes? Answering these questions will allow us to understand important macroevolutionary patterns in a fully aquatic mammalian group and provides baseline data on species for which we have limited biological information because of logistical limitations.
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Affiliation(s)
- Rachel Racicot
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturkundemuseum, Frankfurt am Main, Germany.,Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
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9
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On the waiting time until coordinated mutations get fixed in regulatory sequences. J Theor Biol 2021; 524:110657. [PMID: 33675769 DOI: 10.1016/j.jtbi.2021.110657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 02/13/2021] [Accepted: 02/24/2021] [Indexed: 11/23/2022]
Abstract
In this paper we consider the time evolution of a population of size N with overlapping generations, in the vicinity of m genes. We assume that this population is subject to point mutations, genetic drift, and selection. More specifically, we analyze the statistical distribution of the waiting time Tm until the expression of these genes have changed for all individuals, when transcription factors recognize and attach to short DNA-sequences (binding sites) within regulatory sequences in the neighborhoods of the m genes. The evolutionary dynamics is described by a multitype Moran process, where each individual is assigned a m×L regulatory array that consists of regulatory sequences with L nucleotides for all m genes. We study how the waiting time distribution depends on the number of genes, the mutation rate, the length of the binding sites, the length of the regulatory sequences, and the way in which the targeted binding sites are coordinated for different genes in terms of selection coefficients. These selection coefficients depend on how many binding sites have appeared so far, and possibly on their order of appearance. We also allow for back mutations, whereby some acquired binding sites may be lost over time. It is further assumed that the mutation rate is small enough to warrant a fixed state population, so that all individuals have the same regulatory array, at any given time point, until the next successful mutation arrives in some individual and spreads to the rest of the population. We further incorporate stochastic tunneling, whereby successful mutations get mutated before their fixation. A crucial part of our approach is to divide the huge state space of regulatory arrays into a small number of components, assuming that the array component varies as a Markov process over time. This implies that Tm is the time until this Markov process hits an absorbing state, with a phase-type distribution. A number of interesting results can be derived from our general setup, for instance that the expected waiting time increases exponentially with m, for a selectively neutral model, when back-mutations are possible.
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10
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Groves SL, Peredo CM, Pyenson ND. What are the limits on whale ear bone size? Non-isometric scaling of the cetacean bulla. PeerJ 2021; 9:e10882. [PMID: 33604200 PMCID: PMC7869665 DOI: 10.7717/peerj.10882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/11/2021] [Indexed: 02/02/2023] Open
Abstract
The history of cetaceans demonstrates dramatic macroevolutionary changes that have aided their transformation from terrestrial to obligate aquatic mammals. Their fossil record shows extensive anatomical modifications that facilitate life in a marine environment. To better understand the constraints on this transition, we examined the physical dimensions of the bony auditory complex, in relation to body size, for both living and extinct cetaceans. We compared the dimensions of the tympanic bulla, a conch-shaped ear bone unique to cetaceans, with bizygomatic width—a proxy for cetacean body size. Our results demonstrate that cetacean ears scale non-isometrically with body size, with about 70% of variation explained by increases in bizygomatic width. Our results, which encompass the breadth of the whale fossil record, size diversity, and taxonomic distribution, suggest that functional auditory capacity is constrained by congruent factors related to cranial morphology, as opposed to allometrically scaling with body size.
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Affiliation(s)
- Sabrina L Groves
- Department of Paleobiology, National Museum of Natural History, Washington, DC, USA.,Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
| | - Carlos Mauricio Peredo
- Department of Paleobiology, National Museum of Natural History, Washington, DC, USA.,Department of Earth and Environmental Science, University of Michigan - Ann Arbor, Ann Arbor, MI, USA.,Department of Marine Biology, Texas A&M University - Galveston, Galveston, TX, USA
| | - Nicholas D Pyenson
- Department of Paleobiology, National Museum of Natural History, Washington, DC, USA.,Department of Paleontology and Geology, Burke Museum of Natural History and Culture, Seattle, WA, USA
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11
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Hipsley CA, Aguilar R, Black JR, Hocknull SA. High-throughput microCT scanning of small specimens: preparation, packing, parameters and post-processing. Sci Rep 2020; 10:13863. [PMID: 32807929 PMCID: PMC7431592 DOI: 10.1038/s41598-020-70970-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 08/04/2020] [Indexed: 12/17/2022] Open
Abstract
High-resolution X-ray microcomputed tomography, or microCT (μCT), enables the digital imaging of whole objects in three dimensions. The power of μCT to visualize internal features without disarticulation makes it particularly valuable for the study of museum collections, which house millions of physical specimens documenting the spatio-temporal patterns of life. Despite the potential for comparative analyses, most μCT studies include limited numbers of museum specimens, due to the challenges of digitizing numerous individuals within a project scope. Here we describe a method for high-throughput μCT scanning of hundreds of small (< 2 cm) specimens in a single container, followed by individual labelling and archival storage. We also explore the effects of various packing materials and multiple specimens per capsule to minimize sample movement that can degrade image quality, and hence μCT investment. We demonstrate this protocol on vertebrate fossils from Queensland Museum, Australia, as part of an effort to track community responses to climate change over evolutionary time. This system can be easily modified for other types of wet and dry material amenable to X-ray attenuation, including geological, botanical and zoological samples, providing greater access to large-scale phenotypic data and adding value to global collections.
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Affiliation(s)
- Christy A Hipsley
- School of BioSciences, University of Melbourne, BioSciences 4, Building 147, Parkville, VIC, 3010, Australia. .,Museums Victoria, GPO Box 666, Melbourne, VIC, 3001, Australia.
| | - Rocio Aguilar
- School of BioSciences, University of Melbourne, BioSciences 4, Building 147, Parkville, VIC, 3010, Australia.,Museums Victoria, GPO Box 666, Melbourne, VIC, 3001, Australia.,School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Jay R Black
- School of Earth Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Scott A Hocknull
- School of BioSciences, University of Melbourne, BioSciences 4, Building 147, Parkville, VIC, 3010, Australia.,Queensland Museum, Geosciences, 122 Gerler Rd., Hendra, QLD, 4011, Australia
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12
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Coombs EJ, Clavel J, Park T, Churchill M, Goswami A. Wonky whales: the evolution of cranial asymmetry in cetaceans. BMC Biol 2020; 18:86. [PMID: 32646447 PMCID: PMC7350770 DOI: 10.1186/s12915-020-00805-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/01/2020] [Indexed: 11/10/2022] Open
Abstract
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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Affiliation(s)
- Ellen J Coombs
- Genetics, Evolution, and Environment Department, University College London, Gower Street, London, WC1E 6BT, UK.
- Department of Life Sciences, Natural History Museum, London, Cromwell Road, London, SW7 5BD, UK.
| | - Julien Clavel
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, F-69622, Villeurbanne, France
| | - Travis Park
- Department of Life Sciences, Natural History Museum, London, Cromwell Road, London, SW7 5BD, UK
- Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, UK
| | - Morgan Churchill
- Department of Biology, University of Wisconsin-Oshkosh, Oshkosh, WI, 54901, USA
| | - Anjali Goswami
- Genetics, Evolution, and Environment Department, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Life Sciences, Natural History Museum, London, Cromwell Road, London, SW7 5BD, UK
- Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, UK
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13
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Martins MCI, Park T, Racicot R, Cooper N. Intraspecific variation in the cochleae of harbour porpoises (Phocoena phocoena) and its implications for comparative studies across odontocetes. PeerJ 2020; 8:e8916. [PMID: 32322439 PMCID: PMC7161573 DOI: 10.7717/peerj.8916] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 03/15/2020] [Indexed: 12/19/2022] Open
Abstract
In morphological traits, variation within species is generally considered to be lower than variation among species, although this assumption is rarely tested. This is particularly important in fields like palaeontology, where it is common to use a single individual as representative of a species due to the rarity of fossils. Here, we investigated intraspecific variation in the cochleae of harbour porpoises (Phocoena phocoena). Interspecific variation of cochlear morphology is well characterised among odontocetes (toothed whales) because of the importance of the structure in echolocation, but generally these studies use only a single cochlea to represent each species. In this study we compare variation within the cochleae of 18 specimens of P. phocoena with variations in cochlear morphology across 51 other odontocete species. Using both 3D landmark and linear measurement data, we performed Generalised Procrustes and principal component analyses to quantify shape variation. We then quantified intraspecific variation in our sample of P. phocoena by estimating disparity and the coefficient of variation for our 3D and linear data respectively. Finally, to determine whether intraspecific variation may confound the results of studies of interspecific variation, we used multivariate and univariate analyses of variance to test whether variation within the specimens of P. phocoena was significantly lower than that across odontocetes. We found low levels of intraspecific variation in the cochleae of P. phocoena, and that cochlear shape within P. phocoena was significantly less variable than across odontocetes. Although future studies should attempt to use multiple cochleae for every species, our results suggest that using just one cochlea for each species should not strongly influence the conclusions of comparative studies if our results are consistent across Cetacea.
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Affiliation(s)
- Maria Clara Iruzun Martins
- Division of Biosciences, University College London, University of London, London, United Kingdom.,Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Travis Park
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Earth Sciences, University of Oxford, Oxford, United Kingdom
| | - Rachel Racicot
- Forschungsinstitut und Naturkundemuseum, Senckenberg der SNG, Frankfurt am Main, Germany.,The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, United States of America.,Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN, United States of America.,Department of Zoology, Smithsonian Museum of Natural History, Washington, DC, United States of America
| | - Natalie Cooper
- Department of Life Sciences, Natural History Museum, London, United Kingdom
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14
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Bianucci G, de Muizon C, Urbina M, Lambert O. Extensive Diversity and Disparity of the Early Miocene Platanistoids (Cetacea, Odontoceti) in the Southeastern Pacific (Chilcatay Formation, Peru). Life (Basel) 2020; 10:life10030027. [PMID: 32197480 PMCID: PMC7151620 DOI: 10.3390/life10030027] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 11/27/2022] Open
Abstract
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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Affiliation(s)
- Giovanni Bianucci
- Dipartimento di Scienze della Terra, Università di Pisa, 56126 Pisa, Italy
- Correspondence:
| | - Christian de Muizon
- CR2P (CNRS, MNHN, SU), Muséum National d’Histoire Naturelle, Département Origines et Évolution, 75005 Paris, France;
| | - Mario Urbina
- Departamento de Paleontología de Vertebrados, Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Lima 15072, Peru;
| | - Olivier Lambert
- Institut Royal des Sciences Naturelles de Belgique, D.O. Terre et Histoire de la Vie, 1000 Brussels, Belgium
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15
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Racicot RA, Boessenecker RW, Darroch SAF, Geisler JH. Evidence for convergent evolution of ultrasonic hearing in toothed whales (Cetacea: Odontoceti). Biol Lett 2019; 15:20190083. [PMID: 31088283 DOI: 10.1098/rsbl.2019.0083] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
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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Affiliation(s)
- Rachel A Racicot
- 1 W.M. Keck Science Department, Claremont McKenna, Pitzer, and Scripps Colleges , Claremont, CA 91711 , USA.,2 Vertebrate Paleontology Department and The Dinosaur Institute, Natural History Museum of Los Angeles County , Los Angeles, CA 90007 , USA.,3 Department of Earth and Environmental Sciences, Vanderbilt University , Nashville, TN 37340 , USA
| | - Robert W Boessenecker
- 4 Department of Geology and Environmental Geosciences, College of Charleston , Charleston, SC 29414 , USA
| | - Simon A F Darroch
- 3 Department of Earth and Environmental Sciences, Vanderbilt University , Nashville, TN 37340 , USA
| | - Jonathan H Geisler
- 5 Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine , Old Westbury, NY 11568 , USA
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16
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Park T, Mennecart B, Costeur L, Grohé C, Cooper N. Convergent evolution in toothed whale cochleae. BMC Evol Biol 2019; 19:195. [PMID: 31651234 PMCID: PMC6813997 DOI: 10.1186/s12862-019-1525-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 10/01/2019] [Indexed: 11/10/2022] Open
Abstract
Background Odontocetes (toothed whales) are the most species-rich marine mammal lineage. The catalyst for their evolutionary success is echolocation - a form of biological sonar that uses high-frequency sound, produced in the forehead and ultimately detected by the cochlea. The ubiquity of echolocation in odontocetes across a wide range of physical and acoustic environments suggests that convergent evolution of cochlear shape is likely to have occurred. To test this, we used SURFACE; a method that fits Ornstein-Uhlenbeck (OU) models with stepwise AIC (Akaike Information Criterion) to identify convergent regimes on the odontocete phylogeny, and then tested whether convergence in these regimes was significantly greater than expected by chance. Results We identified three convergent regimes: (1) True’s (Mesoplodon mirus) and Cuvier’s (Ziphius cavirostris) beaked whales; (2) sperm whales (Physeter macrocephalus) and all other beaked whales sampled; and (3) pygmy (Kogia breviceps) and dwarf (Kogia sima) sperm whales and Dall’s porpoise (Phocoenoides dalli). Interestingly the ‘river dolphins’, a group notorious for their convergent morphologies and riverine ecologies, do not have convergent cochlear shapes. The first two regimes were significantly convergent, with habitat type and dive type significantly correlated with membership of the sperm whale + beaked whale regime. Conclusions The extreme acoustic environment of the deep ocean likely constrains cochlear shape, causing the cochlear morphology of sperm and beaked whales to converge. This study adds support for cochlear morphology being used to predict the ecology of extinct cetaceans.
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Affiliation(s)
- Travis Park
- Department of Life Sciences, Natural History Museum, Cromwell Road, SW7 5BD, London, UK.
| | - Bastien Mennecart
- Naturhistorisches Museum Basel, Augustinergasse 2, 4001, Basel, Switzerland.,Naturhistorisches Museum Wien, Burgring 7, 1010, Vienna, Austria
| | - Loïc Costeur
- Naturhistorisches Museum Basel, Augustinergasse 2, 4001, Basel, Switzerland
| | - Camille Grohé
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY, 10024, USA.,Laboratory Paleontology Evolution Paleoecosystems Paleoprimatology (PALEVOPRIM) - UMR 7262, CNRS-INEE/University of Poitiers, 86073, Poitiers Cedex 9, France
| | - Natalie Cooper
- Department of Life Sciences, Natural History Museum, Cromwell Road, SW7 5BD, London, UK
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17
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Serio C, Castiglione S, Tesone G, Piccolo M, Melchionna M, Mondanaro A, Di Febbraro M, Raia P. Macroevolution of Toothed Whales Exceptional Relative Brain Size. Evol Biol 2019. [DOI: 10.1007/s11692-019-09485-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Roston RA, Roth VL. Cetacean Skull Telescoping Brings Evolution of Cranial Sutures into Focus. Anat Rec (Hoboken) 2019; 302:1055-1073. [DOI: 10.1002/ar.24079] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/12/2018] [Accepted: 10/21/2018] [Indexed: 01/09/2023]
Affiliation(s)
| | - V. Louise Roth
- Department of Biology; Duke University; Durham North Carolina
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19
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Jensen FH, Johnson M, Ladegaard M, Wisniewska DM, Madsen PT. Narrow Acoustic Field of View Drives Frequency Scaling in Toothed Whale Biosonar. Curr Biol 2018; 28:3878-3885.e3. [DOI: 10.1016/j.cub.2018.10.037] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/12/2018] [Accepted: 10/12/2018] [Indexed: 11/27/2022]
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20
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Liu Z, Qi FY, Xu DM, Zhou X, Shi P. Genomic and functional evidence reveals molecular insights into the origin of echolocation in whales. SCIENCE ADVANCES 2018; 4:eaat8821. [PMID: 30306134 PMCID: PMC6170035 DOI: 10.1126/sciadv.aat8821] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 08/27/2018] [Indexed: 05/15/2023]
Abstract
Echolocation allows toothed whales to adapt to underwater habitats where vision is ineffective. Because echolocation requires the ability to detect exceptional high-frequency sounds, fossils related to the auditory system can help to pinpoint the origin of echolocation in whales. However, because of conflicting interpretations of archaeocete fossils, when and how whales evolved the high-frequency hearing correlated with echolocation remain unclear. We address these questions at the molecular level by systematically investigating the convergent evolution of 7206 orthologs across 16 mammals and find that convergent genes between the last common ancestor of all whales (LCAW) and echolocating bats are not significantly enriched in functional categories related to hearing, and that convergence in hearing-related proteins between them is not stronger than that between nonecholocating mammalian lineages and echolocating bats. However, these results contrast with those of parallel analyses between the LCA of toothed whales (LCATW) and echolocating bats. Furthermore, we reconstruct the ancestral genes for the hearing protein prestin for the LCAW and LCATW; we show that the LCAW prestin exhibits the same function as that of nonecholocating mammals, but the LCATW prestin shows functional convergence with that of extant echolocating mammals. Mutagenesis shows that functional convergence of prestin is driven by convergent changes in the prestins S392A and L497M in the LCATW and echolocating bats. Our results provide genomic and functional evidence supporting the origin of high-frequency hearing in the LCAW, not the LCATW, and reveal molecular insights into the origin and evolutionary trajectories of echolocation in whales.
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Affiliation(s)
- Zhen Liu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Fei-Yan Qi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming 650223, China
| | - Dong-Ming Xu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Xin Zhou
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
| | - Peng Shi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
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21
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Marx FG, Park T, Fitzgerald EMG, Evans AR. A Miocene pygmy right whale fossil from Australia. PeerJ 2018; 6:e5025. [PMID: 29942692 PMCID: PMC6016540 DOI: 10.7717/peerj.5025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 05/31/2018] [Indexed: 11/28/2022] Open
Abstract
Neobalaenines are an enigmatic group of baleen whales represented today by a single living species: the pygmy right whale, Caperea marginata, found only in the Southern Hemisphere. Molecular divergence estimates date the origin of pygmy right whales to 22–26 Ma, yet so far there are only three confirmed fossil occurrences. Here, we describe an isolated periotic from the latest Miocene of Victoria (Australia). The new fossil shows all the hallmarks of Caperea, making it the second-oldest described neobalaenine, and the oldest record of the genus. Overall, the new specimen resembles C. marginata in its external morphology and details of the cochlea, but is more archaic in it having a hypertrophied suprameatal area and a greater number of cochlear turns. The presence of Caperea in Australian waters during the Late Miocene matches the distribution of the living species, and supports a southern origin for pygmy right whales.
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Affiliation(s)
- Felix G Marx
- Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,School of Biological Sciences, Monash University, Clayton, Victoria, Australia.,Palaeontology, Museums Victoria, Melbourne, Victoria, Australia
| | - Travis Park
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia.,Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Erich M G Fitzgerald
- Palaeontology, Museums Victoria, Melbourne, Victoria, Australia.,Department of Life Sciences, Natural History Museum, London, United Kingdom.,National Museum of Natural History, Smithsonian Institution, Washington, D.C., United States of America
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia.,Palaeontology, Museums Victoria, Melbourne, Victoria, Australia
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22
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Goldbogen JA, Madsen PT. The evolution of foraging capacity and gigantism in cetaceans. ACTA ACUST UNITED AC 2018; 221:221/11/jeb166033. [PMID: 29895582 DOI: 10.1242/jeb.166033] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The extant diversity and rich fossil record of cetaceans provides an extraordinary evolutionary context for investigating the relationship between form, function and ecology. The transition from terrestrial to marine ecosystems is associated with a complex suite of morphological and physiological adaptations that were required for a fully aquatic mammalian life history. Two specific functional innovations that characterize the two great clades of cetaceans, echolocation in toothed whales (Odontoceti) and filter feeding in baleen whales (Mysticeti), provide a powerful comparative framework for integrative studies. Both clades exhibit gigantism in multiple species, but we posit that large body size may have evolved for different reasons and in response to different ecosystem conditions. Although these foraging adaptations have been studied using a combination of experimental and tagging studies, the precise functional drivers and consequences of morphological change within and among these lineages remain less understood. Future studies that focus at the interface of physiology, ecology and paleontology will help elucidate how cetaceans became the largest predators in aquatic ecosystems worldwide.
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Affiliation(s)
- J A Goldbogen
- Department of Biology, Hopkins Marine Station, Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
| | - P T Madsen
- Zoophysiology, Department of Bioscience, Aarhus University, C.F. Møllers Allé 3, 8000 Aarhus C, Denmark.,Aarhus Institute of Advanced Studies, Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark
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23
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The bony labyrinth of toothed whales reflects both phylogeny and habitat preferences. Sci Rep 2018; 8:7841. [PMID: 29777194 PMCID: PMC5959912 DOI: 10.1038/s41598-018-26094-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 04/20/2018] [Indexed: 11/08/2022] Open
Abstract
The inner ear of toothed whales (odontocetes) is known to have evolved particular shapes related to their abilities to echolocate and move under water. While the origin of these capacities is now more and more examined, thanks to new imaging techniques, little is still known about how informative inner ear shape could be to tackle phylogenetic issues or questions pertaining to the habitat preferences of extinct species. Here we show that the shape of the bony labyrinth of toothed whales provides key information both about phylogeny and habitat preferences (freshwater versus coastal and fully marine habitats). Our investigation of more than 20 species of extinct and modern odontocetes shows that the semi-circular canals are not very informative, in contrast to baleen whales, while the cochlea alone bears a strong signal. Inner ear shape thus provides a novel source of information to distinguish between morphologically convergent lineages (e.g. river dolphins).
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24
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Fordyce RE, Marx FG. Gigantism Precedes Filter Feeding in Baleen Whale Evolution. Curr Biol 2018; 28:1670-1676.e2. [PMID: 29754903 DOI: 10.1016/j.cub.2018.04.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/19/2018] [Accepted: 04/06/2018] [Indexed: 10/16/2022]
Abstract
Baleen whales (Mysticeti) are the largest animals on Earth, thanks to their ability to filter huge volumes of small prey from seawater. Mysticetes appeared during the Late Eocene, but evidence of their early evolution remains both sparse and controversial [1, 2], with several models competing to explain the origin of baleen-based bulk feeding [3-6]. Here, we describe a virtually complete skull of Llanocetus denticrenatus, the second-oldest (ca. 34 Ma) mysticete known. The new material represents the same individual as the type and only specimen, a fragmentary mandible. Phylogenetic analysis groups Llanocetus with the oldest mysticete, Mystacodon selenensis [2], into the basal family Llanocetidae. Llanocetus is gigantic (body length ∼8 m) compared to other early mysticetes [7-9]. The broad rostrum has sharp, widely spaced teeth with marked dental abrasion and attrition, suggesting biting and occlusal shearing. As in extant mysticetes, the palate bears many sulci, commonly interpreted as osteological correlates of baleen [3]. Unexpectedly, these sulci converge on the upper alveoli, suggesting a peri-dental blood supply to well-developed gums, rather than to inter-alveolar racks of baleen. We interpret Llanocetus as a raptorial or suction feeder, revealing that whales evolved gigantism well before the emergence of filter feeding. Rather than driving the origin of mysticetes, baleen and filtering most likely only arose after an initial phase of suction-assisted raptorial feeding [2, 4, 5]. This scenario differs strikingly from that proposed for odontocetes, whose defining adaptation-echolocation-was present even in their earliest representatives [10].
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Affiliation(s)
- R Ewan Fordyce
- Department of Geology, University of Otago, Dunedin, New Zealand; Departments of Vertebrate Zoology and Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Felix G Marx
- Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium; School of Biological Sciences, Monash University, Clayton, VIC, Australia; Geosciences, Museum Victoria, Melbourne, VIC, Australia.
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25
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Churchill M, Geisler JH, Beatty BL, Goswami A. Evolution of cranial telescoping in echolocating whales (Cetacea: Odontoceti). Evolution 2018; 72:1092-1108. [DOI: 10.1111/evo.13480] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/23/2018] [Indexed: 12/01/2022]
Affiliation(s)
- Morgan Churchill
- Department of Biology University of Wisconsin Oshkosh Oshkosh Wisconsin 54901
- Department of Anatomy, College of Osteopathic Medicine New York Institute of Technology Old Westbury New York 11568
| | - Jonathan H. Geisler
- Department of Biology University of Wisconsin Oshkosh Oshkosh Wisconsin 54901
| | - Brian L. Beatty
- Department of Biology University of Wisconsin Oshkosh Oshkosh Wisconsin 54901
| | - Anjali Goswami
- Life Sciences Department The Natural History Museum London SW7 5BD United Kingdom
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26
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Abstract
ABSTRACT
The Odontocetes (toothed whales) possess two types of specialized fat and, therefore, represent an interesting group when considering the evolution and function of adipose tissue. All whales have a layer of superficial blubber, which insulates and streamlines, provides buoyancy and acts as an energy reserve. Some toothed whales deposit large amounts of wax esters, rather than triacylglycerols, in blubber, which is unusual. Waxes have very different physical and physiological properties, which may impact blubber function. The cranial acoustic fat depots serve to focus sound during echolocation and hearing. The acoustic fats have unique morphologies; however, they are even more specialized biochemically because they are composed of a mix of endogenous waxes and triacylglycerols with unusual branched elements (derived from amino acids) that are not present in other mammals. Both waxes and branched elements alter how sound travels through a fat body; they are arranged in a 3D topographical pattern to focus sound. Furthermore, the specific branched-chain acid/alcohol synthesis mechanisms and products vary phylogenetically (e.g. dolphins synthesize lipids from leucine whereas beaked whales use valine). I propose that these specialized lipids evolved first in the head: wax synthesis first emerged to serve an acoustic function in toothed whales, with branched-chain synthesis adding additional acoustic focusing power, and some species secondarily retained wax synthesis pathways for blubber. Further research is necessary to elucidate specific molecular mechanisms controlling the synthesis and deposition of wax esters and branched-chain fatty acids, as well as their spatial deposition within tissues and within adipocytes.
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Affiliation(s)
- Heather N. Koopman
- Biology & Marine Biology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28401, USA
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27
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Boessenecker RW, Fraser D, Churchill M, Geisler JH. A toothless dwarf dolphin (Odontoceti: Xenorophidae) points to explosive feeding diversification of modern whales (Neoceti). Proc Biol Sci 2018; 284:rspb.2017.0531. [PMID: 28835549 DOI: 10.1098/rspb.2017.0531] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 07/17/2017] [Indexed: 11/12/2022] Open
Abstract
Toothed whales (Odontoceti) are adapted for catching prey underwater and possess some of the most derived feeding specializations of all mammals, including the loss of milk teeth (monophyodonty), high tooth count (polydonty), and the loss of discrete tooth classes (homodonty). Many extant odontocetes possess some combination of short, broad rostra, reduced tooth counts, fleshy lips, and enlarged hyoid bones-all adaptations for suction feeding upon fishes and squid. We report a new fossil odontocete from the Oligocene (approx. 30 Ma) of South Carolina (Inermorostrum xenops, gen. et sp. nov.) that possesses adaptations for suction feeding: toothlessness and a shortened rostrum (brevirostry). Enlarged foramina on the rostrum suggest the presence of enlarged lips or perhaps vibrissae. Phylogenetic analysis firmly places Inermorostrum within the Xenorophidae, an early diverging odontocete clade typified by long-snouted, heterodont dolphins. Inermorostrum is the earliest obligate suction feeder within the Odontoceti, a feeding mode that independently evolved several times within the clade. Analysis of macroevolutionary trends in rostral shape indicate stabilizing selection around an optimum rostral shape over the course of odontocete evolution, and a post-Eocene explosion in feeding morphology, heralding the diversity of feeding behaviour among modern Odontoceti.
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Affiliation(s)
- Robert W Boessenecker
- Department of Geology and Environmental Geosciences, College of Charleston, Charleston, SC 29424, USA .,University of California Museum of Paleontology, University of California, Berkeley, CA 94720, USA
| | - Danielle Fraser
- Palaeobiology, Canadian Museum of Nature, PO Box 3443 Stn 'D', Ottawa, Ontario, Canada K1P 6P4
| | - Morgan Churchill
- Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA.,Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI 54901, USA
| | - Jonathan H Geisler
- Department of Anatomy, College of Osteopathic Medicine, New York Institute of Technology, Old Westbury, NY 11568, USA
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28
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Park T, Evans AR, Gallagher SJ, Fitzgerald EMG. Low-frequency hearing preceded the evolution of giant body size and filter feeding in baleen whales. Proc Biol Sci 2018; 284:rspb.2016.2528. [PMID: 28179519 DOI: 10.1098/rspb.2016.2528] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/11/2017] [Indexed: 11/12/2022] Open
Abstract
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.
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Affiliation(s)
- Travis Park
- School of Biological Sciences, Monash University, Melbourne, Australia .,Geosciences, Museums Victoria, Melbourne, Australia
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Australia.,Geosciences, Museums Victoria, Melbourne, Australia
| | | | - Erich M G Fitzgerald
- Geosciences, Museums Victoria, Melbourne, Australia.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.,Department of Life Sciences, Natural History Museum, London, UK
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29
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Boessenecker RW, Ahmed E, Geisler JH. New records of the dolphin Albertocetus meffordorum (Odontoceti: Xenorophidae) from the lower Oligocene of South Carolina: Encephalization, sensory anatomy, postcranial morphology, and ontogeny of early odontocetes. PLoS One 2017; 12:e0186476. [PMID: 29117197 PMCID: PMC5695589 DOI: 10.1371/journal.pone.0186476] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 10/02/2017] [Indexed: 11/18/2022] Open
Abstract
We report five new specimens of xenorophid dolphins from North and South Carolina. Four of the specimens represent the xenorophid Albertocetus meffordorum, previously only known from the holotype skull. The other is a fragmentary petrosal from the upper Oligocene Belgrade Formation that we refer to Echovenator sp, indicating at least two xenorophids from that unit. Two of the Albertocetus meffordorum specimens are from the lower Oligocene Ashley Formation: 1) a partial skeleton with neurocranium, fragmentary mandible, ribs, vertebrae, and chevrons, and 2) an isolated braincase. The partial vertebral column indicates that Albertocetus retained the ancestral morphology and locomotory capabilities of basilosaurid archaeocetes, toothed mysticetes, and physeteroids, and caudal vertebrae that are as wide as tall suggest that the caudal peduncle, which occurs in all extant Cetacea, was either wide or lacking. CT data from the isolated braincase were used to generate a digital endocast of the cranial cavity. The estimated EQ of this specimen is relatively high for an Oligocene odontocete, and other aspects of the brain, such as its anteroposterior length and relative size of the temporal lobe, are intermediate in morphology between those of extant cetaceans and terrestrial artiodactyls. Ethmoturbinals are also preserved, and are similar in morphology and number to those described for the Miocene odontocete Squalodon. These fossils extend the temporal range of Albertocetus meffordorum into the early Oligocene, its geographic range into South Carolina, and expand our paleobiological understanding of the Xenorophidae.
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Affiliation(s)
- Robert W. Boessenecker
- Department of Geology and Environmental Geosciences, College of Charleston, Charleston, South Carolina, United States of America
- University of California Museum of Paleontology, University of California, Berkeley, California, United States of America
- * E-mail:
| | - Erum Ahmed
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, United States of America
| | - Jonathan H. Geisler
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, New York, United States of America
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Infrasonic and Ultrasonic Hearing Evolved after the Emergence of Modern Whales. Curr Biol 2017; 27:1776-1781.e9. [DOI: 10.1016/j.cub.2017.04.061] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/31/2017] [Accepted: 04/27/2017] [Indexed: 11/17/2022]
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Park T, Marx FG, Fitzgerald EMG, Evans AR. The cochlea of the enigmatic pygmy right whale Caperea marginata informs mysticete phylogeny. J Morphol 2017; 278:801-809. [PMID: 28333389 DOI: 10.1002/jmor.20674] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 02/09/2017] [Accepted: 02/27/2017] [Indexed: 11/07/2022]
Abstract
The pygmy right whale, Caperea marginata, is the least understood extant baleen whale (Cetacea, Mysticeti). Knowledge on its basic anatomy, ecology, and fossil record is limited, even though its singular position outside both balaenids (right whales) and balaenopteroids (rorquals + grey whales) gives Caperea a pivotal role in mysticete evolution. Recent investigations of the cetacean cochlea have provided new insights into sensory capabilities and phylogeny. Here, we extend this advance to Caperea by describing, for the first time, the inner ear of this enigmatic species. The cochlea is large and appears to be sensitive to low-frequency sounds, but its hearing limit is relatively high. The presence of a well-developed tympanal recess links Caperea with cetotheriids and balaenopteroids, rather than balaenids, contrary to the traditional morphological view of a close Caperea-balaenid relationship. Nevertheless, a broader sample of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level.
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Affiliation(s)
- Travis Park
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.,Geosciences, Museum Victoria, Melbourne, Victoria, Australia
| | - Felix G Marx
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.,Geosciences, Museum Victoria, Melbourne, Victoria, Australia.,Directorate of Earth and History of Life, Royal Belgian Institute of Natural Sciences, Brussels, Belgium
| | - Erich M G Fitzgerald
- Geosciences, Museum Victoria, Melbourne, Victoria, Australia.,National Museum of Natural History, Smithsonian Institution, Washington, DC.,Department of Vertebrate Zoology, Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.,Geosciences, Museum Victoria, Melbourne, Victoria, Australia
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Ekdale EG. Morphological variation among the inner ears of extinct and extant baleen whales (Cetacea: Mysticeti). J Morphol 2016; 277:1599-1615. [PMID: 27627739 DOI: 10.1002/jmor.20610] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/12/2016] [Accepted: 08/22/2016] [Indexed: 11/06/2022]
Abstract
Living mysticetes (baleen whales) and odontocetes (toothed whales) differ significantly in auditory function in that toothed whales are sensitive to high-frequency and ultrasonic sound vibrations and mysticetes to low-frequency and infrasonic noises. Our knowledge of the evolution and phylogeny of cetaceans, and mysticetes in particular, is at a point at which we can explore morphological and physiological changes within the baleen whale inner ear. Traditional comparative anatomy and landmark-based 3D-geometric morphometric analyses were performed to investigate the anatomical diversity of the inner ears of extinct and extant mysticetes in comparison with other cetaceans. Principal component analyses (PCAs) show that the cochlear morphospace of odontocetes is tangential to that of mysticetes, but odontocetes are completely separated from mysticetes when semicircular canal landmarks are combined with the cochlear data. The cochlea of the archaeocete Zygorhiza kochii and early diverging extinct mysticetes plot within the morphospace of crown mysticetes, suggesting that mysticetes possess ancestral cochlear morphology and physiology. The PCA results indicate variation among mysticete species, although no major patterns are recovered to suggest separate hearing or locomotor regimes. Phylogenetic signal was detected for several clades, including crown Cetacea and crown Mysticeti, with the most clades expressing phylogenetic signal in the semicircular canal dataset. Brownian motion could not be excluded as an explanation for the signal, except for analyses combining cochlea and semicircular canal datasets for Balaenopteridae. J. Morphol. 277:1599-1615, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Eric G Ekdale
- Department of Biology, San Diego State University, San Diego, California.,Department of Paleontology, San Diego Natural History Museum, San Diego, California
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Lambert O. Evolution: Fossil Ears and Underwater Sonar. Curr Biol 2016; 26:R758-60. [DOI: 10.1016/j.cub.2016.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Churchill M, Martinez-Caceres M, de Muizon C, Mnieckowski J, Geisler J. The Origin of High-Frequency Hearing in Whales. Curr Biol 2016; 26:2144-9. [DOI: 10.1016/j.cub.2016.06.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 10/21/2022]
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Racicot RA, Gearty W, Kohno N, Flynn JJ. Comparative anatomy of the bony labyrinth of extant and extinct porpoises (Cetacea: Phocoenidae). Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12857] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Rachel A. Racicot
- The Dinosaur Institute; Natural History Museum of Los Angeles County; Los Angeles CA USA
- Smithsonian Institution; P. O. Box 37012 MRC 121 Washington DC 20013-7012 USA
| | - William Gearty
- Department of Geological Sciences; Stanford University; Stanford CA USA
| | - Naoki Kohno
- Department of Geology and Paleontology; Division of Biotic Evolution; National Museum of Nature and Science; Tokyo Japan
- Graduate School of Life and Environmental Sciences; University of Tsukuba; Japan
| | - John J. Flynn
- Department of Vertebrate Paleontology; Division of Paleontology; American Museum of Natural History; New York NY USA
- Richard Gilder Graduate School; American Museum of Natural History; New York NY USA
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