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De Vreese S, Orekhova K, Morell M, Gerussi T, Graïc JM. Neuroanatomy of the Cetacean Sensory Systems. Animals (Basel) 2023; 14:66. [PMID: 38200796 PMCID: PMC10778493 DOI: 10.3390/ani14010066] [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: 09/28/2023] [Revised: 11/10/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Cetaceans have undergone profound sensory adaptations in response to their aquatic environment during evolution. These adaptations are characterised by anatomo-functional changes in the classically defined sensory systems, shaping their neuroanatomy accordingly. This review offers a concise and up-to-date overview of our current understanding of the neuroanatomy associated with cetacean sensory systems. It encompasses a wide spectrum, ranging from the peripheral sensory cells responsible for detecting environmental cues, to the intricate structures within the central nervous system that process and interpret sensory information. Despite considerable progress in this field, numerous knowledge gaps persist, impeding a comprehensive and integrated understanding of their sensory adaptations, and through them, of their sensory perspective. By synthesising recent advances in neuroanatomical research, this review aims to shed light on the intricate sensory alterations that differentiate cetaceans from other mammals and allow them to thrive in the marine environment. Furthermore, it highlights pertinent knowledge gaps and invites future investigations to deepen our understanding of the complex processes in cetacean sensory ecology and anatomy, physiology and pathology in the scope of conservation biology.
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Affiliation(s)
- Steffen De Vreese
- Laboratory of Applied Bioacoustics (LAB), Universitat Politècnica de Catalunya-BarcelonaTech (UPC), 08800 Vilanova i la Geltrú, Spain
| | - Ksenia Orekhova
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Maria Morell
- Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Germany;
| | - Tommaso Gerussi
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
| | - Jean-Marie Graïc
- Department of Comparative Biomedicine and Food Science (BCA), University of Padova, 35020 Legnaro, Italy; (K.O.); (T.G.); (J.-M.G.)
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2
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Ancient whale rhodopsin reconstructs dim-light vision over a major evolutionary transition: Implications for ancestral diving behavior. Proc Natl Acad Sci U S A 2022; 119:e2118145119. [PMID: 35759662 PMCID: PMC9271160 DOI: 10.1073/pnas.2118145119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cetaceans are fully aquatic mammals that descended from terrestrial ancestors, an iconic evolutionary transition characterized by adaptations for underwater foraging via breath-hold diving. Although the evolutionary history of this specialized behavior is challenging to reconstruct, coevolving sensory systems may offer valuable clues. The dim-light visual pigment, rhodopsin, which initiates phototransduction in the rod photoreceptors of the eye, has provided insight into the visual ecology of depth in several aquatic vertebrate lineages. Here, we use ancestral sequence reconstruction and protein resurrection experiments to quantify light-activation metrics in rhodopsin pigments from ancestors bracketing the cetacean terrestrial-to-aquatic transition. By comparing multiple reconstruction methods on a broadly sampled cetartiodactyl species tree, we generated highly robust ancestral sequence estimates. Our experimental results provide direct support for a blue-shift in spectral sensitivity along the branch separating cetaceans from terrestrial relatives. This blue-shift was 14 nm, resulting in a deep-sea signature (λmax = 486 nm) similar to many mesopelagic-dwelling fish. We also discovered that the decay rates of light-activated rhodopsin increased in ancestral cetaceans, which may indicate an accelerated dark adaptation response typical of deeper-diving mammals. Because slow decay rates are thought to help sequester cytotoxic photoproducts, this surprising result could reflect an ecological trade-off between rod photoprotection and dark adaptation. Taken together, these ancestral shifts in rhodopsin function suggest that some of the first fully aquatic cetaceans could dive into the mesopelagic zone (>200 m). Moreover, our reconstructions indicate that this behavior arose before the divergence of toothed and baleen whales.
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3
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Churchill M, Baltz C. Evolution of orbit size in toothed whales (Artiodactyla: Odontoceti). J Anat 2021; 239:1419-1437. [PMID: 34287886 PMCID: PMC8602015 DOI: 10.1111/joa.13522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/05/2021] [Accepted: 07/08/2021] [Indexed: 11/30/2022] Open
Abstract
For many marine tetrapods, vision is important for finding food and navigating underwater, and eye size has increased to improve the capture of light in dim ocean depths. Odontocete whales, in contrast, rely instead on echolocation for navigation and prey capture. We tested whether the evolution of echolocation has influenced the orbit size, a proxy for eye size, and examined how orbit size evolved over time. We also assessed variation in orbit size amongst whales and tested how body size, diving ability, sound production, foraging habitat, and prey capture strategy influenced the orbit size using phylogenetic independent contrasts and phylogenetic ANOVAs. Using measurements of orbit length and bizygomatic width, we calculated proportional orbit size for 70 extant and 29 extinct whale taxa, with an emphasis on Odontoceti. We then performed ancestral character state reconstruction on a time-calibrated composite phylogeny. Our analysis revealed that there was no shift in proportional orbit size from archaeocetes through stem odontocetes, indicating that the evolution of echolocation did not influence the orbit size. Proportional orbit size increased in Ziphiidae, Phocoenidae, and Cephalorhynchus. Proportional orbit size decreased in Balaenidae, Physeteridae, Platanistidae, and Lipotidae. Body size, diving ability, foraging environment, and prey capture strategy had a significant influence on orbit size, but only without phylogenetic correction. An increase in orbit size is associated with deep diving behavior in beaked whales, while progenesis and retention of juvenile features into adulthood explain the pattern observed in Phocoenidae and Cephalorhynchus. Decrease in proportional orbit size is associated with adaptation toward murky freshwater environments in odontocetes and skim feeding in balaenids. Our study reveals that the evolution of echolocation had little effect on orbit size, which is variable in whales, and that adaptation for different feeding modes and habitat explains some of this variance.
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Affiliation(s)
- Morgan Churchill
- Department of BiologyUniversity of Wisconsin OshkoshOshkoshWIUSA
| | - Colin Baltz
- Department of BiologyUniversity of Wisconsin OshkoshOshkoshWIUSA
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4
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Ito RK, Harada S, Tabata R, Watanabe K. Molecular evolution and convergence of the rhodopsin gene in Gymnogobius, a goby group having diverged into coastal to freshwater habitats. J Evol Biol 2021; 35:333-346. [PMID: 34689368 DOI: 10.1111/jeb.13955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/03/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022]
Abstract
Adaptive evolution of vision-related genes has been frequently observed in the process of invasion of new environments in a wide range of animal taxa. The typical example is that of the molecular evolution of rhodopsin associated with habitat changes in aquatic animals. However, few studies have investigated rhodopsin evolution during adaptive radiation across various habitats. In the present study, we examined the link between molecular evolutionary patterns in the rhodopsin gene and macroscopic habitat changes in Gymnogobius species (Gobiidae), which have adaptively radiated to diverse aquatic habitats including the sea, brackish waters, rivers and lakes. Analysis of amino acid substitutions in rhodopsin in the phylogenetic framework revealed convergent substitutions in 4-5 amino acids in three groups (four species), including two spectral tuning amino acid sites known to change rhodopsin's absorption wavelength. Positive selection was detected in the basal branches of each of these three groups, suggesting adaptive molecular convergence of rhodopsin. However, no significant correlation was observed between amino acid substitutions and the species' habitat changes, suggesting molecular adaptation to some unidentified micro-ecological environments. Taken together, these results emphasize the importance of considering not only macroscopic habitats but also micro-ecological environments when elucidating the driving forces of adaptive evolution of the visual system.
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Affiliation(s)
- Ryosuke K Ito
- Division of Biological Sciences, Department of Zoology, Graduate School of Science, Kyoto University, Kyoto City, Japan
| | - Shigeo Harada
- Resource Management Division, Fisheries Bureau, Agriculture, Forestry and Fisheries Department, Wakayama Prefectural Government, Wakayama City, Japan
| | | | - Katsutoshi Watanabe
- Division of Biological Sciences, Department of Zoology, Graduate School of Science, Kyoto University, Kyoto City, Japan
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5
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Fasick JI, Algrain H, Samuels C, Mahadevan P, Schweikert LE, Naffaa ZJ, Robinson PR. Spectral tuning and deactivation kinetics of marine mammal melanopsins. PLoS One 2021; 16:e0257436. [PMID: 34653198 PMCID: PMC8519484 DOI: 10.1371/journal.pone.0257436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/31/2021] [Indexed: 02/04/2023] Open
Abstract
In mammals, the photopigment melanopsin (Opn4) is found in a subset of retinal ganglion cells that serve light detection for circadian photoentrainment and pupil constriction (i.e., mydriasis). For a given species, the efficiency of photoentrainment and length of time that mydriasis occurs is determined by the spectral sensitivity and deactivation kinetics of melanopsin, respectively, and to date, neither of these properties have been described in marine mammals. Previous work has indicated that the absorbance maxima (λmax) of marine mammal rhodopsins (Rh1) have diversified to match the available light spectra at foraging depths. However, similar to the melanopsin λmax of terrestrial mammals (~480 nm), the melanopsins of marine mammals may be conserved, with λmax values tuned to the spectrum of solar irradiance at the water's surface. Here, we investigated the Opn4 pigments of 17 marine mammal species inhabiting diverse photic environments including the Infraorder Cetacea, as well as the Orders Sirenia and Carnivora. Both genomic and cDNA sequences were used to deduce amino acid sequences to identify substitutions most likely involved in spectral tuning and deactivation kinetics of the Opn4 pigments. Our results show that there appears to be no amino acid substitutions in marine mammal Opn4 opsins that would result in any significant change in λmax values relative to their terrestrial counterparts. We also found some marine mammal species to lack several phosphorylation sites in the carboxyl terminal domain of their Opn4 pigments that result in significantly slower deactivation kinetics, and thus longer mydriasis, compared to terrestrial controls. This finding was restricted to cetacean species previously found to lack cone photoreceptor opsins, a condition known as rod monochromacy. These results suggest that the rod monochromat whales rely on extended pupillary constriction to prevent photobleaching of the highly photosensitive all-rod retina when moving between photopic and scotopic conditions.
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Affiliation(s)
- Jeffry I. Fasick
- Department of Biological Sciences, The University of Tampa, Tampa, Florida, United States of America
| | - Haya Algrain
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
| | - Courtland Samuels
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Padmanabhan Mahadevan
- Department of Biological Sciences, The University of Tampa, Tampa, Florida, United States of America
| | - Lorian E. Schweikert
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
| | - Zaid J. Naffaa
- Department of Biological Sciences, Kean University, Union, New Jersey, United States of America
| | - Phyllis R. Robinson
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland, United States of America
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6
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Seiko T, Kishida T, Toyama M, Hariyama T, Okitsu T, Wada A, Toda M, Satta Y, Terai Y. Visual adaptation of opsin genes to the aquatic environment in sea snakes. BMC Evol Biol 2020; 20:158. [PMID: 33243140 PMCID: PMC7690139 DOI: 10.1186/s12862-020-01725-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 11/22/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolutionary transitions from terrestrial to aquatic life history cause drastic changes in sensory systems. Indeed, the drastic changes in vision have been reported in many aquatic amniotes, convergently. Recently, the opsin genes of the full-aquatic sea snakes have been reported. However, those of the amphibious sea snakes have not been examined in detail. RESULTS Here, we investigated opsin genes and visual pigments of sea snakes. We determined the sequences of SWS1, LWS, and RH1 genes from one terrestrial, three amphibious and four fully-aquatic elapids. Amino acid replacements at four and one spectra-tuning positions were found in LWS and RH1, respectively. We measured or predicted absorption of LWS and RH1 pigments with A1-derived retinal. During their evolution, blue shifts of LWS pigments have occurred stepwise in amphibious sea snakes and convergently in both amphibious and fully-aquatic species. CONCLUSIONS Blue shifted LWS pigments may have adapted to deep water or open water environments dominated by blue light. The evolution of opsins differs between marine mammals (cetaceans and pinnipeds) and sea snakes in two fundamental ways: (1) pseudogenization of opsins in marine mammals; and (2) large blue shifts of LWS pigments in sea snakes. It may be possible to explain these two differences at the level of photoreceptor cell composition given that cone and rod cells both exist in mammals whereas only cone cells exist in fully-aquatic sea snakes. We hypothesize that the differences in photoreceptor cell compositions may have differentially affected the evolution of opsins in divergent amniote lineages.
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Affiliation(s)
- Takashi Seiko
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193 Japan
| | - Takushi Kishida
- Wildlife Research Center, Kyoto University, 2-24 Tanaka Sekiden-cho, Sakyo, Kyoto 606-8203 Japan
| | - Mina Toyama
- Department of Biology, Faculty of Medicine, Hamamatsu University School of Medicine, Handayama, Hamamatsu Japan
| | - Takahiko Hariyama
- Department of Biology, Faculty of Medicine, Hamamatsu University School of Medicine, Handayama, Hamamatsu Japan
| | - Takashi Okitsu
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, 4-19-1, Motoyamakita, Higashinada, Kobe, 658-8558 Japan
| | - Akimori Wada
- Laboratory of Organic Chemistry for Life Science, Kobe Pharmaceutical University, 4-19-1, Motoyamakita, Higashinada, Kobe, 658-8558 Japan
| | - Mamoru Toda
- Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa 903-0213 Japan
| | - Yoko Satta
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193 Japan
| | - Yohey Terai
- Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Kanagawa 240-0193 Japan
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7
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Rolland J, Silvestro D, Litsios G, Faye L, Salamin N. Clownfishes evolution below and above the species level. Proc Biol Sci 2019; 285:rspb.2017.1796. [PMID: 29467260 PMCID: PMC5832698 DOI: 10.1098/rspb.2017.1796] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/29/2018] [Indexed: 12/26/2022] Open
Abstract
The difference between rapid morphological evolutionary changes observed in populations and the long periods of stasis detected in the fossil record has raised a decade-long debate about the exact role played by intraspecific mechanisms at the interspecific level. Although they represent different scales of the same evolutionary process, micro- and macroevolution are rarely studied together and few empirical studies have compared the rates of evolution and the selective pressures between both scales. Here, we analyse morphological, genetic and ecological traits in clownfishes at different evolutionary scales and demonstrate that the tempo of molecular and morphological evolution at the species level can be, to some extent, predicted from parameters estimated below the species level, such as the effective population size or the rate of evolution within populations. We also show that similar codons in the gene of the rhodopsin RH1, a light-sensitive receptor protein, are under positive selection at the intra and interspecific scales, suggesting that similar selective pressures are acting at both levels.
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Affiliation(s)
- Jonathan Rolland
- Department of Computational Biology, University of Lausanne, Biophore, Quartier-Sorge, 1015 Lausanne, Switzerland .,Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland.,Department of Zoology, University of British Columbia, #4200-6270 University Blvd, Vancouver, BC, Canada
| | - Daniele Silvestro
- Department of Computational Biology, University of Lausanne, Biophore, Quartier-Sorge, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland.,Department of Biological and Environmental Sciences, University of Gothenburg, Carl Skottsbergs gata 22B, Gothenburg 41319, Sweden.,Gothenburg Global Biodiversity Centre, Box 461, SE-405 30 Gothenburg, Sweden
| | - Glenn Litsios
- Department of Computational Biology, University of Lausanne, Biophore, Quartier-Sorge, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland
| | - Laurélène Faye
- Department of Computational Biology, University of Lausanne, Biophore, Quartier-Sorge, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland.,Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
| | - Nicolas Salamin
- Department of Computational Biology, University of Lausanne, Biophore, Quartier-Sorge, 1015 Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge, 1015 Lausanne, Switzerland
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8
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Borges R, Johnson WE, O'Brien SJ, Gomes C, Heesy CP, Antunes A. Adaptive genomic evolution of opsins reveals that early mammals flourished in nocturnal environments. BMC Genomics 2018; 19:121. [PMID: 29402215 PMCID: PMC5800076 DOI: 10.1186/s12864-017-4417-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 12/22/2017] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Based on evolutionary patterns of the vertebrate eye, Walls (1942) hypothesized that early placental mammals evolved primarily in nocturnal habitats. However, not only Eutheria, but all mammals show photic characteristics (i.e. dichromatic vision, rod-dominated retina) suggestive of a scotopic eye design. RESULTS Here, we used integrative comparative genomic and phylogenetic methodologies employing the photoreceptive opsin gene family in 154 mammals to test the likelihood of a nocturnal period in the emergence of all mammals. We showed that mammals possess genomic patterns concordant with a nocturnal ancestry. The loss of the RH2, VA, PARA, PARIE and OPN4x opsins in all mammals led us to advance a probable and most-parsimonious hypothesis of a global nocturnal bottleneck that explains the loss of these genes in the emerging lineage (> > 215.5 million years ago). In addition, ancestral character reconstruction analyses provided strong evidence that ancestral mammals possessed a nocturnal lifestyle, ultra-violet-sensitive vision, low visual acuity and low orbit convergence (i.e. panoramic vision). CONCLUSIONS Overall, this study provides insight into the evolutionary history of the mammalian eye while discussing important ecological aspects of the photic paleo-environments ancestral mammals have occupied.
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Affiliation(s)
- Rui Borges
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208, Porto, Portugal
- Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal
| | - Warren E Johnson
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA, 22630, USA
| | - Stephen J O'Brien
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, St. Petersburg, Russia, 199004
- Guy Harvey Oceanographic Center, Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, 8000, North Ocean Drive, Ft Lauderdale, 33004, Florida, USA
| | - Cidália Gomes
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208, Porto, Portugal
- ICBAS, Institute of the Biomedical Sciences of Abel Salazar, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313, Porto, Portugal
| | - Christopher P Heesy
- Department of Anatomy, Arizona College of Osteopathic Medicine, Midwestern University, 19555 N. 59th avenue, Glendale, AZ, USA
| | - Agostinho Antunes
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208, Porto, Portugal.
- Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
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9
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Cronin TW, Fasick JI, Schweikert LE, Johnsen S, Kezmoh LJ, Baumgartner MF. Coping with copepods: do right whales ( Eubalaena glacialis) forage visually in dark waters? Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0067. [PMID: 28193812 DOI: 10.1098/rstb.2016.0067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2016] [Indexed: 11/12/2022] Open
Abstract
North Atlantic right whales (Eubalaena glacialis) feed during the spring and early summer in marine waters off the northeast coast of North America. Their food primarily consists of planktonic copepods, Calanus finmarchicus, which they consume in large numbers by ram filter feeding. The coastal waters where these whales forage are turbid, but they successfully locate copepod swarms during the day at depths exceeding 100 m, where light is very dim and copepod patches may be difficult to see. Using models of E. glacialis visual sensitivity together with measurements of light in waters near Cape Cod where they feed and of light attenuation by living copepods in seawater, we evaluated the potential for visual foraging by these whales. Our results suggest that vision may be useful for finding copepod patches, particularly if E. glacialis searches overhead for silhouetted masses or layers of copepods. This should permit the whales to locate C. finmarchicus visually throughout most daylight hours at depths throughout their foraging range. Looking laterally, the whales might also be able to see copepod patches at short range near the surface.This article is part of the themed issue 'Vision in dim light'.
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Affiliation(s)
- Thomas W Cronin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Jeffry I Fasick
- Department of Biological Sciences, The University of Tampa, Tampa, FL 33606, USA
| | - Lorian E Schweikert
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA.,Biology Department, Duke University, Durham, NC 27708, USA
| | - Sönke Johnsen
- Biology Department, Duke University, Durham, NC 27708, USA
| | - Lorren J Kezmoh
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Mark F Baumgartner
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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10
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Hauser FE, Ilves KL, Schott RK, Castiglione GM, López-Fernández H, Chang BSW. Accelerated Evolution and Functional Divergence of the Dim Light Visual Pigment Accompanies Cichlid Colonization of Central America. Mol Biol Evol 2017; 34:2650-2664. [PMID: 28957507 DOI: 10.1093/molbev/msx192] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cichlids encompass one of the most diverse groups of fishes in South and Central America, and show extensive variation in life history, morphology, and colouration. While studies of visual system evolution in cichlids have focussed largely on the African rift lake species flocks, Neotropical cichlids offer a unique opportunity to investigate visual system evolution at broader temporal and geographic scales. South American cichlid colonization of Central America has likely promoted accelerated rates of morphological evolution in Central American lineages as they encountered reduced competition, renewed ecological opportunity, and novel aquatic habitats. To investigate whether such transitions have influenced molecular evolution of vision in Central American cichlids, we sequenced the dim-light rhodopsin gene in 101 Neotropical cichlid species, spanning the diversity of the clade. We find strong evidence for increased rates of evolution in Central American cichlid rhodopsin relative to South American lineages, and identify several sites under positive selection in rhodopsin that likely contribute to adaptation to different photic environments. We expressed a Neotropical cichlid rhodopsin protein invitro for the first time, and found that while its spectral tuning properties were characteristic of typical vertebrate rhodopsin pigments, the rate of decay of its active signalling form was much slower, consistent with dim light adaptation in other vertebrate rhodopsins. Using site-directed mutagenesis combined with spectroscopic assays, we found that a key amino acid substitution present in some Central American cichlids accelerates the rate of decay of active rhodopsin, which may mediate adaptation to clear water habitats.
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Affiliation(s)
- Frances E Hauser
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Katriina L Ilves
- Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
- Department of Biology, Pace University, New York, NY
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Gianni M Castiglione
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Natural History, Royal Ontario Museum, Toronto, ON, Canada
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
- Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON, Canada
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11
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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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A Link No Longer Missing: New Evidence for the Cetotheriid Affinities of Caperea. PLoS One 2016; 11:e0164059. [PMID: 27711216 PMCID: PMC5053404 DOI: 10.1371/journal.pone.0164059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 09/19/2016] [Indexed: 11/19/2022] Open
Abstract
The origins of the enigmatic pygmy right whale Caperea marginata, the only living member of its subfamily (Neobalaeninae), are an outstanding mystery of cetacean evolution. Its strikingly disparate morphology sets Caperea apart from all other whales, and has turned it into a wildcard taxon that holds the key to understanding modern baleen whale diversity. Morphological cladistics generally ally this species with right whales, whereas molecular analyses consistently cluster it with rorquals and grey whales (Balaenopteroidea). A recent study potentially resolved this conflict by proposing that Caperea belongs with the otherwise extinct Cetotheriidae, but has been strongly criticised on morphological grounds. Evidence from the neobalaenine fossil record could potentially give direct insights into morphological transitions, but is currently limited to just a single species: the Late Miocene Miocaperea pulchra, from Peru. We show that Miocaperea has a highly unusual morphology of the auditory region, resulting from a–presumably feeding-related–strengthening of the articulation of the hyoid apparatus with the skull. This distinctive arrangement is otherwise only found in the extinct Cetotheriidae, which makes Miocaperea a “missing link” that demonstrates the origin of pygmy right whales from cetotheriids, and confirms the latter’s resurrection from the dead.
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Fasick JI, Robinson PR. Adaptations of Cetacean Retinal Pigments to Aquatic Environments. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Schweikert LE, Fasick JI, Grace MS. Evolutionary loss of cone photoreception in balaenid whales reveals circuit stability in the mammalian retina. J Comp Neurol 2016; 524:2873-85. [DOI: 10.1002/cne.23996] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 02/26/2016] [Accepted: 03/04/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Lorian E. Schweikert
- Department of Biological SciencesFlorida Institute of TechnologyMelbourne Florida32901
| | - Jeffry I. Fasick
- Department of Biological SciencesThe University of TampaTampa Florida33606
| | - Michael S. Grace
- Department of Biological SciencesFlorida Institute of TechnologyMelbourne Florida32901
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Dungan SZ, Kosyakov A, Chang BS. Spectral Tuning of Killer Whale (Orcinus orca) Rhodopsin: Evidence for Positive Selection and Functional Adaptation in a Cetacean Visual Pigment. Mol Biol Evol 2015; 33:323-36. [DOI: 10.1093/molbev/msv217] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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McGowen MR, Gatesy J, Wildman DE. Molecular evolution tracks macroevolutionary transitions in Cetacea. Trends Ecol Evol 2014; 29:336-46. [DOI: 10.1016/j.tree.2014.04.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 04/02/2014] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
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Schott RK, Refvik SP, Hauser FE, López-Fernández H, Chang BSW. Divergent positive selection in rhodopsin from lake and riverine cichlid fishes. Mol Biol Evol 2014; 31:1149-65. [PMID: 24509690 DOI: 10.1093/molbev/msu064] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Studies of cichlid evolution have highlighted the importance of visual pigment genes in the spectacular radiation of the African rift lake cichlids. Recent work, however, has also provided strong evidence for adaptive diversification of riverine cichlids in the Neotropics, which inhabit environments of markedly different spectral properties from the African rift lakes. These ecological and/or biogeographic differences may have imposed divergent selective pressures on the evolution of the cichlid visual system. To test these hypotheses, we investigated the molecular evolution of the dim-light visual pigment, rhodopsin. We sequenced rhodopsin from Neotropical and African riverine cichlids and combined these data with published sequences from African cichlids. We found significant evidence for positive selection using random sites codon models in all cichlid groups, with the highest levels in African lake cichlids. Tests using branch-site and clade models that partitioned the data along ecological (lake, river) and/or biogeographic (African, Neotropical) boundaries found significant evidence of divergent selective pressures among cichlid groups. However, statistical comparisons among these models suggest that ecological, rather than biogeographic, factors may be responsible for divergent selective pressures that have shaped the evolution of the visual system in cichlids. We found that branch-site models did not perform as well as clade models for our data set, in which there was evidence for positive selection in the background. One of our most intriguing results is that the amino acid sites found to be under positive selection in Neotropical and African lake cichlids were largely nonoverlapping, despite falling into the same three functional categories: spectral tuning, retinal uptake/release, and rhodopsin dimerization. Taken together, these results would imply divergent selection across cichlid clades, but targeting similar functions. This study highlights the importance of molecular investigations of ecologically important groups and the flexibility of clade models in explicitly testing ecological hypotheses.
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Affiliation(s)
- Ryan K Schott
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Meredith RW, Gatesy J, Emerling CA, York VM, Springer MS. Rod monochromacy and the coevolution of cetacean retinal opsins. PLoS Genet 2013; 9:e1003432. [PMID: 23637615 PMCID: PMC3630094 DOI: 10.1371/journal.pgen.1003432] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/15/2013] [Indexed: 01/02/2023] Open
Abstract
Cetaceans have a long history of commitment to a fully aquatic lifestyle that extends back to the Eocene. Extant species have evolved a spectacular array of adaptations in conjunction with their deployment into a diverse array of aquatic habitats. Sensory systems are among those that have experienced radical transformations in the evolutionary history of this clade. In the case of vision, previous studies have demonstrated important changes in the genes encoding rod opsin (RH1), short-wavelength sensitive opsin 1 (SWS1), and long-wavelength sensitive opsin (LWS) in selected cetaceans, but have not examined the full complement of opsin genes across the complete range of cetacean families. Here, we report protein-coding sequences for RH1 and both color opsin genes (SWS1, LWS) from representatives of all extant cetacean families. We examine competing hypotheses pertaining to the timing of blue shifts in RH1 relative to SWS1 inactivation in the early history of Cetacea, and we test the hypothesis that some cetaceans are rod monochomats. Molecular evolutionary analyses contradict the "coastal" hypothesis, wherein SWS1 was pseudogenized in the common ancestor of Cetacea, and instead suggest that RH1 was blue-shifted in the common ancestor of Cetacea before SWS1 was independently knocked out in baleen whales (Mysticeti) and in toothed whales (Odontoceti). Further, molecular evidence implies that LWS was inactivated convergently on at least five occasions in Cetacea: (1) Balaenidae (bowhead and right whales), (2) Balaenopteroidea (rorquals plus gray whale), (3) Mesoplodon bidens (Sowerby's beaked whale), (4) Physeter macrocephalus (giant sperm whale), and (5) Kogia breviceps (pygmy sperm whale). All of these cetaceans are known to dive to depths of at least 100 m where the underwater light field is dim and dominated by blue light. The knockout of both SWS1 and LWS in multiple cetacean lineages renders these taxa rod monochromats, a condition previously unknown among mammalian species.
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Affiliation(s)
- Robert W. Meredith
- Department of Biology, University of California Riverside, Riverside, California, United States of America
- Department of Biology and Molecular Biology, Montclair State University, Montclair, New Jersey, United States of America
| | - John Gatesy
- Department of Biology, University of California Riverside, Riverside, California, United States of America
| | - Christopher A. Emerling
- Department of Biology, University of California Riverside, Riverside, California, United States of America
| | - Vincent M. York
- Department of Biology, University of California Riverside, Riverside, California, United States of America
- Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Mark S. Springer
- Department of Biology, University of California Riverside, Riverside, California, United States of America
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Fordyce RE, Marx FG. The pygmy right whale Caperea marginata: the last of the cetotheres. Proc Biol Sci 2012; 280:20122645. [PMID: 23256199 DOI: 10.1098/rspb.2012.2645] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The pygmy right whale, Caperea marginata, is the most enigmatic of the living baleen whales (Mysticeti). Its highly disparate morphology and the virtual absence of a described fossil record have made it extremely difficult to place Caperea into a broader evolutionary context, and molecular and morphological studies have frequently contradicted each other as to the origins and phylogenetic relationships of the species. Our study of a wealth of material from New Zealand collections, representing a wide range of ontogenetic stages, has identified several new features previously unreported in Caperea, which suggest that the pygmy right whale may be the last survivor of the supposedly extinct family Cetotheriidae. This hypothesis is corroborated by both morphology-based and total evidence cladistic analyses, including 166 morphological characters and 23 taxa, representing all the living and extinct families of toothless baleen whales. Our results allow us to formally refer Caperea to Cetotheriidae, thus resurrecting the latter from extinction and helping to clarify the origins of a long-problematic living species.
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Affiliation(s)
- R Ewan Fordyce
- Department of Geology, University of Otago, 360 Leith Walk, PO Box 56, Dunedin, Otago 9016, New Zealand
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