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Tamborini M. A Plea for a New Synthesis: From Twentieth-Century Paleobiology to Twenty-First-Century Paleontology and Back Again. BIOLOGY 2022; 11:1120. [PMID: 35892976 PMCID: PMC9394316 DOI: 10.3390/biology11081120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/22/2022] [Accepted: 07/24/2022] [Indexed: 11/16/2022]
Abstract
In this paper, I will briefly discuss the elements of novelty and continuity between twentieth-century paleobiology and twenty-first-century paleontology. First, I will outline the heated debate over the disciplinary status of paleontology in the mid-twentieth century. Second, I will analyze the main theoretical issue behind this debate by considering two prominent case studies within the broader paleobiology agenda. Third, I will turn to twenty-first century paleontology and address five representative research topics. In doing so, I will characterize twenty-first century paleontology as a science that strives for more data, more technology, and more integration. Finally, I will outline what twenty-first-century paleontology might inherit from twentieth-century paleobiology: the pursuit of and plea for a new synthesis that could lead to a second paleobiological revolution. Following in the footsteps of the paleobiological revolution of the 1960s and 1970s, the paleobiological revolution of the twenty-first century would enable paleontologists to gain strong political representation and argue with a decisive voice at the "high table" on issues such as the expanded evolutionary synthesis, the conservation of Earth's environment, and global climate change.
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Affiliation(s)
- Marco Tamborini
- Department of Philosophy, Technische Universität Darmstadt, Marktplatz 15 (Residenzschloss), 64283 Darmstadt, Germany
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2
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Kalaj BN, Ni QZ, La Clair JJ, Deheyn DD, Burkart MD. Chemoenzymatic Isolation and Characterization of High Purity Mammalian Melanin. Chembiochem 2022; 23:e202200021. [PMID: 35318787 DOI: 10.1002/cbic.202200021] [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: 01/11/2022] [Revised: 02/28/2022] [Indexed: 11/10/2022]
Abstract
Although melanin is one of the most ubiquitous polymers in living systems, our understanding of its molecular structure, biosynthesis and biophysical properties has been limited to only a small number of organisms other than humans. This is in part due to the difficulty associated with isolating pure melanin. While purification methods exist, they typically involve harsh treatments with strong acid/base conditions combined with elevated temperatures that can lead to the polymer backbone degradation. To be successful, a viable isolation method must deliver a selective, yet complete degradation of non-melanin biopolymers as well as remove small molecule metabolites that are not integrative to the melanin backbone. Here, we demonstrate the use of chemoenzymatic processing guided by fluorescent probes for the purification and isolation of native mammalian melanin without significant induction of chemical degradation. This multi-step purification-tracking methodology enables quantitative isolation of pure melanin from mammalian tissue for spectroscopic characterization.
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Affiliation(s)
- Brianna N Kalaj
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA
| | - Qing Zhe Ni
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA
| | - James J La Clair
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA
| | - Dimitri D Deheyn
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive La Jolla, California, 92093-0202, USA
| | - Michael D Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA
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Hendrickx C, Bell PR, Pittman M, Milner ARC, Cuesta E, O'Connor J, Loewen M, Currie PJ, Mateus O, Kaye TG, Delcourt R. Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs. Biol Rev Camb Philos Soc 2022; 97:960-1004. [PMID: 34991180 DOI: 10.1111/brv.12829] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.
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Affiliation(s)
- Christophe Hendrickx
- Unidad Ejecutora Lillo, CONICET-Fundación Miguel Lillo, 251 Miguel Lillo, San Miguel de Tucumán, Tucumán, 4000, Argentina
| | - Phil R Bell
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Michael Pittman
- Vertebrate Palaeontology Laboratory, Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China.,Department of Earth Sciences, University College London, WC1E 6BT, United Kingdom
| | - Andrew R C Milner
- St. George Dinosaur Discovery Site at Johnson Farm, 2180 East Riverside Drive, St. George, UT, U.S.A
| | - Elena Cuesta
- Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, Munich, 80333, Germany
| | - Jingmai O'Connor
- Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL, 60605, U.S.A
| | - Mark Loewen
- Department of Geology and Geophysics, University of Utah, Frederick Albert Sutton Building, 115 South 1460 East, Salt Lake City, UT, 84112, U.S.A.,Natural History Museum of Utah, 301 Wakara Way, Salt Lake City, UT, 84108, U.S.A
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, 95 Rua João Luis de Moura, Lourinhã, 2530-158, Portugal
| | - Thomas G Kaye
- Foundation for Scientific Advancement, 7023 Alhambra Dr., Sierra Vista, AZ, 85650, U.S.A
| | - Rafael Delcourt
- Universidade Estadual de Campinas (UNICAMP), Instituto de Geociências, Cidade Universitária, Rua Carlos Gomes, 250, Campinas, SP, 13083-855, Brazil
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Roy A, Pittman M, Saitta ET, Kaye TG, Xu X. Recent advances in amniote palaeocolour reconstruction and a framework for future research. Biol Rev Camb Philos Soc 2020; 95:22-50. [PMID: 31538399 PMCID: PMC7004074 DOI: 10.1111/brv.12552] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 08/12/2019] [Accepted: 08/15/2019] [Indexed: 01/24/2023]
Abstract
Preserved melanin pigments have been discovered in fossilised integumentary appendages of several amniote lineages (fishes, frogs, snakes, marine reptiles, non-avialan dinosaurs, birds, and mammals) excavated from lagerstätten across the globe. Melanisation is a leading factor in organic integument preservation in these fossils. Melanin in extant vertebrates is typically stored in rod- to sphere-shaped, lysosome-derived, membrane-bound vesicles called melanosomes. Black, dark brown, and grey colours are produced by eumelanin, and reddish-brown colours are produced by phaeomelanin. Specific morphotypes and nanostructural arrangements of melanosomes and their relation to the keratin matrix in integumentary appendages create the so-called 'structural colours'. Reconstruction of colour patterns in ancient animals has opened an exciting new avenue for studying their life, behaviour and ecology. Modern relationships between the shape, arrangement, and size of avian melanosomes, melanin chemistry, and feather colour have been applied to reconstruct the hues and colour patterns of isolated feathers and plumages of the dinosaurs Anchiornis, Sinosauropteryx, and Microraptor in seminal papers that initiated the field of palaeocolour reconstruction. Since then, further research has identified countershading camouflage patterns, and informed subsequent predictions on the ecology and behaviour of these extinct animals. However, palaeocolour reconstruction remains a nascent field, and current approaches have considerable potential for further refinement, standardisation, and expansion. This includes detailed study of non-melanic pigments that might be preserved in fossilised integuments. A common issue among existing palaeocolour studies is the lack of contextualisation of different lines of evidence and the wide variety of techniques currently employed. To that end, this review focused on fossil amniotes: (i) produces an overarching framework that appropriately reconstructs palaeocolour by accounting for the chemical signatures of various pigments, morphology and local arrangement of pigment-bearing vesicles, pigment concentration, macroscopic colour patterns, and taphonomy; (ii) provides background context for the evolution of colour-producing mechanisms; and (iii) encourages future efforts in palaeocolour reconstructions particularly of less-studied groups such as non-dinosaur archosaurs and non-archosaur amniotes.
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Affiliation(s)
- Arindam Roy
- Vertebrate Palaeontology Laboratory, Department of Earth SciencesThe University of Hong KongPokfulamHong Kong SARChina
| | - Michael Pittman
- Vertebrate Palaeontology Laboratory, Department of Earth SciencesThe University of Hong KongPokfulamHong Kong SARChina
| | - Evan T. Saitta
- Integrative Research Center, Section of Earth SciencesField Museum of Natural History1400 S. Lake Shore Drive, ChicagoIL60605U.S.A.
| | - Thomas G. Kaye
- Foundation for Scientific Advancement7023 Alhambra Drive, Sierra VistaAZ85650U.S.A.
| | - Xing Xu
- Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences142 Xizhimenwai Street.Beijing100044China
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Camacho C, Negro JJ, Redondo I, Palacios S, Sáez-Gómez P. Correlates of individual variation in the porphyrin-based fluorescence of red-necked nightjars (Caprimulgus ruficollis). Sci Rep 2019; 9:19115. [PMID: 31836769 PMCID: PMC6910967 DOI: 10.1038/s41598-019-55522-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 11/28/2019] [Indexed: 11/19/2022] Open
Abstract
Many nocturnal animals, including invertebrates such as scorpions and a variety of vertebrate species, including toadlets, flying squirrels, owls, and nightjars, emit bright fluorescence under ultraviolet light. However, the ecological significance of this unique coloration so attached to nocturnality remains obscure. Here, we used an intensively studied population of migratory red-necked nightjars (Caprimulgus ruficollis) to investigate inter-individual variation in porphyrin-based pink fluorescence according to sex, age, body condition, time of the year, and the extent of white plumage patches known to be involved in sexual communication. Males and females exhibited a similar extent of pink fluorescence on the under-side of the wings in both juvenile and adult birds, but males had larger white patches than females. Body condition predicted the extent of pink fluorescence in juvenile birds, but not in adults. On average, the extent of pink fluorescence in juveniles increased by ca. 20% for every 10-g increase in body mass. For both age classes, there was a slight seasonal increase (1–4% per week) in the amount of fluorescence. Our results suggest that the porphyrin-based coloration of nightjars might signal individual quality, at least in their first potential breeding season, although the ability of these and other nocturnal birds to perceive fluorescence remains to be unequivocally proven.
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Affiliation(s)
- Carlos Camacho
- Department of Evolutionary Ecology, Estación Biológica de Doñana (EBD-CSIC), Av. Américo Vespucio 26, 41092, Seville, Spain.,Department of Biology, Centre for Animal Movement Research (CAnMove). Lund University. Ecology Building, 223 62, Lund, Sweden
| | - Juan José Negro
- Department of Evolutionary Ecology, Estación Biológica de Doñana (EBD-CSIC), Av. Américo Vespucio 26, 41092, Seville, Spain.
| | - Iraida Redondo
- Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal 2, 28006, Madrid, Spain
| | - Sebastián Palacios
- Monitoring Team of Natural Processes (ICTS-RBD). Estación Biológica de Doñana (EBD-CSIC), Av. Américo Vespucio 26, 41092, Seville, Spain
| | - Pedro Sáez-Gómez
- Department of Integrative Sciences, University of Huelva, Campus Universitario El Carmen, Av. Andalucía, 21071, Huelva, Spain.,Instituto Multidisciplinar para el Estudio del Medio "Ramón Margalef", Universidad de Alicante, 03080, Alicante, Spain
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Pinheiro FL, Prado G, Ito S, Simon JD, Wakamatsu K, Anelli LE, Andrade JAF, Glass K. Chemical characterization of pterosaur melanin challenges color inferences in extinct animals. Sci Rep 2019; 9:15947. [PMID: 31685890 PMCID: PMC6828676 DOI: 10.1038/s41598-019-52318-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Melanosomes (melanin-bearing organelles) are common in the fossil record occurring as dense packs of globular microbodies. The organic component comprising the melanosome, melanin, is often preserved in fossils, allowing identification of the chemical nature of the constituent pigment. In present-day vertebrates, melanosome morphology correlates with their pigment content in selected melanin-containing structures, and this interdependency is employed in the color reconstruction of extinct animals. The lack of analyses integrating the morphology of fossil melanosomes with the chemical identification of pigments, however, makes these inferences tentative. Here, we chemically characterize the melanin content of the soft tissue headcrest of the pterosaur Tupandactylus imperator by alkaline hydrogen peroxide oxidation followed by high-performance liquid chromatography. Our results demonstrate the unequivocal presence of eumelanin in T. imperator headcrest. Scanning electron microscopy followed by statistical analyses, however, reveal that preserved melanosomes containing eumelanin are undistinguishable to pheomelanin-bearing organelles of extant vertebrates. Based on these new findings, straightforward color inferences based on melanosome morphology may not be valid for all fossil vertebrates, and color reconstructions based on ultrastructure alone should be regarded with caution.
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Affiliation(s)
- Felipe L Pinheiro
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, 97300-162, Brazil.
| | - Gustavo Prado
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil.
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | | | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | - Luiz E Anelli
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil
| | - José A F Andrade
- Centro de Pesquisas Paleontológicas da Chapada do Araripe, Departamento Nacional de Produção Mineral, 63100-440, Crato, Brazil
| | - Keely Glass
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
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Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates. Proc Natl Acad Sci U S A 2019; 116:17880-17889. [PMID: 31427524 PMCID: PMC6731645 DOI: 10.1073/pnas.1820285116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemistries. Tissue-specific chemical signatures can persist in fossils despite some diagenetic overprint, allowing the reconstruction of internal soft-tissue anatomy in fossil vertebrates, and suggest that links between melanin and metal regulation have deep evolutionary origins in vertebrates. Recent discoveries of nonintegumentary melanosomes in extant and fossil amphibians offer potential insights into the physiological functions of melanin not directly related to color production, but the phylogenetic distribution and evolutionary history of these internal melanosomes has not been characterized systematically. Here, we present a holistic method to discriminate among melanized tissues by analyzing the anatomical distribution, morphology, and chemistry of melanosomes in various tissues in a phylogenetically broad sample of extant and fossil vertebrates. Our results show that internal melanosomes in all extant vertebrates analyzed have tissue-specific geometries and elemental signatures. Similar distinct populations of preserved melanosomes in phylogenetically diverse vertebrate fossils often map onto specific anatomical features. This approach also reveals the presence of various melanosome-rich internal tissues in fossils, providing a mechanism for the interpretation of the internal anatomy of ancient vertebrates. Collectively, these data indicate that vertebrate melanins share fundamental physiological roles in homeostasis via the scavenging and sequestering of metals and suggest that intimate links between melanin and metal metabolism in vertebrates have deep evolutionary origins.
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Intermolecular association of some selected melanin monomers and their optical absorption. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Skin Pigmentation: Is the Control of Melanogenesis a Target within Reach? Int J Mol Sci 2018; 19:ijms19124040. [PMID: 30558112 PMCID: PMC6320957 DOI: 10.3390/ijms19124040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/12/2022] Open
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Vahidzadeh E, Kalra AP, Shankar K. Melanin-based electronics: From proton conductors to photovoltaics and beyond. Biosens Bioelectron 2018; 122:127-139. [DOI: 10.1016/j.bios.2018.09.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 01/04/2023]
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